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-rw-r--r--compiler/rustc_codegen_llvm/src/asm.rs1329
1 files changed, 1329 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_llvm/src/asm.rs b/compiler/rustc_codegen_llvm/src/asm.rs
new file mode 100644
index 00000000000..597ebd97365
--- /dev/null
+++ b/compiler/rustc_codegen_llvm/src/asm.rs
@@ -0,0 +1,1329 @@
+use crate::attributes;
+use crate::builder::Builder;
+use crate::common::Funclet;
+use crate::context::CodegenCx;
+use crate::llvm;
+use crate::type_::Type;
+use crate::type_of::LayoutLlvmExt;
+use crate::value::Value;
+
+use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
+use rustc_codegen_ssa::mir::operand::OperandValue;
+use rustc_codegen_ssa::traits::*;
+use rustc_data_structures::fx::FxHashMap;
+use rustc_middle::ty::layout::TyAndLayout;
+use rustc_middle::{bug, span_bug, ty::Instance};
+use rustc_span::{sym, Pos, Span, Symbol};
+use rustc_target::abi::*;
+use rustc_target::asm::*;
+use tracing::debug;
+
+use libc::{c_char, c_uint};
+use smallvec::SmallVec;
+
+impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
+    fn codegen_inline_asm(
+        &mut self,
+        template: &[InlineAsmTemplatePiece],
+        operands: &[InlineAsmOperandRef<'tcx, Self>],
+        options: InlineAsmOptions,
+        line_spans: &[Span],
+        instance: Instance<'_>,
+        dest: Option<Self::BasicBlock>,
+        catch_funclet: Option<(Self::BasicBlock, Option<&Self::Funclet>)>,
+    ) {
+        let asm_arch = self.tcx.sess.asm_arch.unwrap();
+
+        // Collect the types of output operands
+        let mut constraints = vec![];
+        let mut clobbers = vec![];
+        let mut output_types = vec![];
+        let mut op_idx = FxHashMap::default();
+        let mut clobbered_x87 = false;
+        for (idx, op) in operands.iter().enumerate() {
+            match *op {
+                InlineAsmOperandRef::Out { reg, late, place } => {
+                    let is_target_supported = |reg_class: InlineAsmRegClass| {
+                        for &(_, feature) in reg_class.supported_types(asm_arch) {
+                            if let Some(feature) = feature {
+                                if self
+                                    .tcx
+                                    .asm_target_features(instance.def_id())
+                                    .contains(&feature)
+                                {
+                                    return true;
+                                }
+                            } else {
+                                // Register class is unconditionally supported
+                                return true;
+                            }
+                        }
+                        false
+                    };
+
+                    let mut layout = None;
+                    let ty = if let Some(ref place) = place {
+                        layout = Some(&place.layout);
+                        llvm_fixup_output_type(self.cx, reg.reg_class(), &place.layout, instance)
+                    } else if matches!(
+                        reg.reg_class(),
+                        InlineAsmRegClass::X86(
+                            X86InlineAsmRegClass::mmx_reg | X86InlineAsmRegClass::x87_reg
+                        )
+                    ) {
+                        // Special handling for x87/mmx registers: we always
+                        // clobber the whole set if one register is marked as
+                        // clobbered. This is due to the way LLVM handles the
+                        // FP stack in inline assembly.
+                        if !clobbered_x87 {
+                            clobbered_x87 = true;
+                            clobbers.push("~{st}".to_string());
+                            for i in 1..=7 {
+                                clobbers.push(format!("~{{st({})}}", i));
+                            }
+                        }
+                        continue;
+                    } else if !is_target_supported(reg.reg_class())
+                        || reg.reg_class().is_clobber_only(asm_arch)
+                    {
+                        // We turn discarded outputs into clobber constraints
+                        // if the target feature needed by the register class is
+                        // disabled. This is necessary otherwise LLVM will try
+                        // to actually allocate a register for the dummy output.
+                        assert!(matches!(reg, InlineAsmRegOrRegClass::Reg(_)));
+                        clobbers.push(format!("~{}", reg_to_llvm(reg, None)));
+                        continue;
+                    } else {
+                        // If the output is discarded, we don't really care what
+                        // type is used. We're just using this to tell LLVM to
+                        // reserve the register.
+                        dummy_output_type(self.cx, reg.reg_class())
+                    };
+                    output_types.push(ty);
+                    op_idx.insert(idx, constraints.len());
+                    let prefix = if late { "=" } else { "=&" };
+                    constraints.push(format!("{}{}", prefix, reg_to_llvm(reg, layout)));
+                }
+                InlineAsmOperandRef::InOut { reg, late, in_value, out_place } => {
+                    let layout = if let Some(ref out_place) = out_place {
+                        &out_place.layout
+                    } else {
+                        // LLVM required tied operands to have the same type,
+                        // so we just use the type of the input.
+                        &in_value.layout
+                    };
+                    let ty = llvm_fixup_output_type(self.cx, reg.reg_class(), layout, instance);
+                    output_types.push(ty);
+                    op_idx.insert(idx, constraints.len());
+                    let prefix = if late { "=" } else { "=&" };
+                    constraints.push(format!("{}{}", prefix, reg_to_llvm(reg, Some(layout))));
+                }
+                _ => {}
+            }
+        }
+
+        // Collect input operands
+        let mut inputs = vec![];
+        for (idx, op) in operands.iter().enumerate() {
+            match *op {
+                InlineAsmOperandRef::In { reg, value } => {
+                    let llval = llvm_fixup_input(
+                        self,
+                        value.immediate(),
+                        reg.reg_class(),
+                        &value.layout,
+                        instance,
+                    );
+                    inputs.push(llval);
+                    op_idx.insert(idx, constraints.len());
+                    constraints.push(reg_to_llvm(reg, Some(&value.layout)));
+                }
+                InlineAsmOperandRef::InOut { reg, late, in_value, out_place: _ } => {
+                    let value = llvm_fixup_input(
+                        self,
+                        in_value.immediate(),
+                        reg.reg_class(),
+                        &in_value.layout,
+                        instance,
+                    );
+                    inputs.push(value);
+
+                    // In the case of fixed registers, we have the choice of
+                    // either using a tied operand or duplicating the constraint.
+                    // We prefer the latter because it matches the behavior of
+                    // Clang.
+                    if late && matches!(reg, InlineAsmRegOrRegClass::Reg(_)) {
+                        constraints.push(reg_to_llvm(reg, Some(&in_value.layout)).to_string());
+                    } else {
+                        constraints.push(format!("{}", op_idx[&idx]));
+                    }
+                }
+                InlineAsmOperandRef::SymFn { instance } => {
+                    inputs.push(self.cx.get_fn(instance));
+                    op_idx.insert(idx, constraints.len());
+                    constraints.push("s".to_string());
+                }
+                InlineAsmOperandRef::SymStatic { def_id } => {
+                    inputs.push(self.cx.get_static(def_id));
+                    op_idx.insert(idx, constraints.len());
+                    constraints.push("s".to_string());
+                }
+                _ => {}
+            }
+        }
+
+        // Build the template string
+        let mut labels = vec![];
+        let mut template_str = String::new();
+        for piece in template {
+            match *piece {
+                InlineAsmTemplatePiece::String(ref s) => {
+                    if s.contains('$') {
+                        for c in s.chars() {
+                            if c == '$' {
+                                template_str.push_str("$$");
+                            } else {
+                                template_str.push(c);
+                            }
+                        }
+                    } else {
+                        template_str.push_str(s)
+                    }
+                }
+                InlineAsmTemplatePiece::Placeholder { operand_idx, modifier, span: _ } => {
+                    match operands[operand_idx] {
+                        InlineAsmOperandRef::In { reg, .. }
+                        | InlineAsmOperandRef::Out { reg, .. }
+                        | InlineAsmOperandRef::InOut { reg, .. } => {
+                            let modifier = modifier_to_llvm(asm_arch, reg.reg_class(), modifier);
+                            if let Some(modifier) = modifier {
+                                template_str.push_str(&format!(
+                                    "${{{}:{}}}",
+                                    op_idx[&operand_idx], modifier
+                                ));
+                            } else {
+                                template_str.push_str(&format!("${{{}}}", op_idx[&operand_idx]));
+                            }
+                        }
+                        InlineAsmOperandRef::Const { ref string } => {
+                            // Const operands get injected directly into the template
+                            template_str.push_str(string);
+                        }
+                        InlineAsmOperandRef::SymFn { .. }
+                        | InlineAsmOperandRef::SymStatic { .. } => {
+                            // Only emit the raw symbol name
+                            template_str.push_str(&format!("${{{}:c}}", op_idx[&operand_idx]));
+                        }
+                        InlineAsmOperandRef::Label { label } => {
+                            template_str.push_str(&format!("${{{}:l}}", constraints.len()));
+                            constraints.push("!i".to_owned());
+                            labels.push(label);
+                        }
+                    }
+                }
+            }
+        }
+
+        constraints.append(&mut clobbers);
+        if !options.contains(InlineAsmOptions::PRESERVES_FLAGS) {
+            match asm_arch {
+                InlineAsmArch::AArch64 | InlineAsmArch::Arm64EC | InlineAsmArch::Arm => {
+                    constraints.push("~{cc}".to_string());
+                }
+                InlineAsmArch::X86 | InlineAsmArch::X86_64 => {
+                    constraints.extend_from_slice(&[
+                        "~{dirflag}".to_string(),
+                        "~{fpsr}".to_string(),
+                        "~{flags}".to_string(),
+                    ]);
+                }
+                InlineAsmArch::RiscV32 | InlineAsmArch::RiscV64 => {
+                    constraints.extend_from_slice(&[
+                        "~{vtype}".to_string(),
+                        "~{vl}".to_string(),
+                        "~{vxsat}".to_string(),
+                        "~{vxrm}".to_string(),
+                    ]);
+                }
+                InlineAsmArch::Avr => {
+                    constraints.push("~{sreg}".to_string());
+                }
+                InlineAsmArch::Nvptx64 => {}
+                InlineAsmArch::PowerPC | InlineAsmArch::PowerPC64 => {}
+                InlineAsmArch::Hexagon => {}
+                InlineAsmArch::LoongArch64 => {
+                    constraints.extend_from_slice(&[
+                        "~{$fcc0}".to_string(),
+                        "~{$fcc1}".to_string(),
+                        "~{$fcc2}".to_string(),
+                        "~{$fcc3}".to_string(),
+                        "~{$fcc4}".to_string(),
+                        "~{$fcc5}".to_string(),
+                        "~{$fcc6}".to_string(),
+                        "~{$fcc7}".to_string(),
+                    ]);
+                }
+                InlineAsmArch::Mips | InlineAsmArch::Mips64 => {}
+                InlineAsmArch::S390x => {
+                    constraints.push("~{cc}".to_string());
+                }
+                InlineAsmArch::SpirV => {}
+                InlineAsmArch::Wasm32 | InlineAsmArch::Wasm64 => {}
+                InlineAsmArch::Bpf => {}
+                InlineAsmArch::Msp430 => {
+                    constraints.push("~{sr}".to_string());
+                }
+                InlineAsmArch::M68k => {
+                    constraints.push("~{ccr}".to_string());
+                }
+                InlineAsmArch::CSKY => {}
+            }
+        }
+        if !options.contains(InlineAsmOptions::NOMEM) {
+            // This is actually ignored by LLVM, but it's probably best to keep
+            // it just in case. LLVM instead uses the ReadOnly/ReadNone
+            // attributes on the call instruction to optimize.
+            constraints.push("~{memory}".to_string());
+        }
+        let volatile = !options.contains(InlineAsmOptions::PURE);
+        let alignstack = !options.contains(InlineAsmOptions::NOSTACK);
+        let output_type = match &output_types[..] {
+            [] => self.type_void(),
+            [ty] => ty,
+            tys => self.type_struct(tys, false),
+        };
+        let dialect = match asm_arch {
+            InlineAsmArch::X86 | InlineAsmArch::X86_64
+                if !options.contains(InlineAsmOptions::ATT_SYNTAX) =>
+            {
+                llvm::AsmDialect::Intel
+            }
+            _ => llvm::AsmDialect::Att,
+        };
+        let result = inline_asm_call(
+            self,
+            &template_str,
+            &constraints.join(","),
+            &inputs,
+            output_type,
+            &labels,
+            volatile,
+            alignstack,
+            dialect,
+            line_spans,
+            options.contains(InlineAsmOptions::MAY_UNWIND),
+            dest,
+            catch_funclet,
+        )
+        .unwrap_or_else(|| span_bug!(line_spans[0], "LLVM asm constraint validation failed"));
+
+        let mut attrs = SmallVec::<[_; 2]>::new();
+        if options.contains(InlineAsmOptions::PURE) {
+            if options.contains(InlineAsmOptions::NOMEM) {
+                attrs.push(llvm::MemoryEffects::None.create_attr(self.cx.llcx));
+            } else if options.contains(InlineAsmOptions::READONLY) {
+                attrs.push(llvm::MemoryEffects::ReadOnly.create_attr(self.cx.llcx));
+            }
+            attrs.push(llvm::AttributeKind::WillReturn.create_attr(self.cx.llcx));
+        } else if options.contains(InlineAsmOptions::NOMEM) {
+            attrs.push(llvm::MemoryEffects::InaccessibleMemOnly.create_attr(self.cx.llcx));
+        } else {
+            // LLVM doesn't have an attribute to represent ReadOnly + SideEffect
+        }
+        attributes::apply_to_callsite(result, llvm::AttributePlace::Function, &{ attrs });
+
+        // Switch to the 'normal' basic block if we did an `invoke` instead of a `call`
+        if let Some(dest) = dest {
+            self.switch_to_block(dest);
+        }
+
+        // Write results to outputs
+        for (idx, op) in operands.iter().enumerate() {
+            if let InlineAsmOperandRef::Out { reg, place: Some(place), .. }
+            | InlineAsmOperandRef::InOut { reg, out_place: Some(place), .. } = *op
+            {
+                let value = if output_types.len() == 1 {
+                    result
+                } else {
+                    self.extract_value(result, op_idx[&idx] as u64)
+                };
+                let value =
+                    llvm_fixup_output(self, value, reg.reg_class(), &place.layout, instance);
+                OperandValue::Immediate(value).store(self, place);
+            }
+        }
+    }
+}
+
+impl<'tcx> AsmMethods<'tcx> for CodegenCx<'_, 'tcx> {
+    fn codegen_global_asm(
+        &self,
+        template: &[InlineAsmTemplatePiece],
+        operands: &[GlobalAsmOperandRef<'tcx>],
+        options: InlineAsmOptions,
+        _line_spans: &[Span],
+    ) {
+        let asm_arch = self.tcx.sess.asm_arch.unwrap();
+
+        // Default to Intel syntax on x86
+        let intel_syntax = matches!(asm_arch, InlineAsmArch::X86 | InlineAsmArch::X86_64)
+            && !options.contains(InlineAsmOptions::ATT_SYNTAX);
+
+        // Build the template string
+        let mut template_str = String::new();
+        if intel_syntax {
+            template_str.push_str(".intel_syntax\n");
+        }
+        for piece in template {
+            match *piece {
+                InlineAsmTemplatePiece::String(ref s) => template_str.push_str(s),
+                InlineAsmTemplatePiece::Placeholder { operand_idx, modifier: _, span: _ } => {
+                    match operands[operand_idx] {
+                        GlobalAsmOperandRef::Const { ref string } => {
+                            // Const operands get injected directly into the
+                            // template. Note that we don't need to escape $
+                            // here unlike normal inline assembly.
+                            template_str.push_str(string);
+                        }
+                        GlobalAsmOperandRef::SymFn { instance } => {
+                            let llval = self.get_fn(instance);
+                            self.add_compiler_used_global(llval);
+                            let symbol = llvm::build_string(|s| unsafe {
+                                llvm::LLVMRustGetMangledName(llval, s);
+                            })
+                            .expect("symbol is not valid UTF-8");
+                            template_str.push_str(&symbol);
+                        }
+                        GlobalAsmOperandRef::SymStatic { def_id } => {
+                            let llval = self
+                                .renamed_statics
+                                .borrow()
+                                .get(&def_id)
+                                .copied()
+                                .unwrap_or_else(|| self.get_static(def_id));
+                            self.add_compiler_used_global(llval);
+                            let symbol = llvm::build_string(|s| unsafe {
+                                llvm::LLVMRustGetMangledName(llval, s);
+                            })
+                            .expect("symbol is not valid UTF-8");
+                            template_str.push_str(&symbol);
+                        }
+                    }
+                }
+            }
+        }
+        if intel_syntax {
+            template_str.push_str("\n.att_syntax\n");
+        }
+
+        unsafe {
+            llvm::LLVMAppendModuleInlineAsm(
+                self.llmod,
+                template_str.as_ptr().cast(),
+                template_str.len(),
+            );
+        }
+    }
+}
+
+pub(crate) fn inline_asm_call<'ll>(
+    bx: &mut Builder<'_, 'll, '_>,
+    asm: &str,
+    cons: &str,
+    inputs: &[&'ll Value],
+    output: &'ll llvm::Type,
+    labels: &[&'ll llvm::BasicBlock],
+    volatile: bool,
+    alignstack: bool,
+    dia: llvm::AsmDialect,
+    line_spans: &[Span],
+    unwind: bool,
+    dest: Option<&'ll llvm::BasicBlock>,
+    catch_funclet: Option<(&'ll llvm::BasicBlock, Option<&Funclet<'ll>>)>,
+) -> Option<&'ll Value> {
+    let volatile = if volatile { llvm::True } else { llvm::False };
+    let alignstack = if alignstack { llvm::True } else { llvm::False };
+    let can_throw = if unwind { llvm::True } else { llvm::False };
+
+    let argtys = inputs
+        .iter()
+        .map(|v| {
+            debug!("Asm Input Type: {:?}", *v);
+            bx.cx.val_ty(*v)
+        })
+        .collect::<Vec<_>>();
+
+    debug!("Asm Output Type: {:?}", output);
+    let fty = bx.cx.type_func(&argtys, output);
+    unsafe {
+        // Ask LLVM to verify that the constraints are well-formed.
+        let constraints_ok = llvm::LLVMRustInlineAsmVerify(fty, cons.as_ptr().cast(), cons.len());
+        debug!("constraint verification result: {:?}", constraints_ok);
+        if constraints_ok {
+            let v = llvm::LLVMRustInlineAsm(
+                fty,
+                asm.as_ptr().cast(),
+                asm.len(),
+                cons.as_ptr().cast(),
+                cons.len(),
+                volatile,
+                alignstack,
+                dia,
+                can_throw,
+            );
+
+            let call = if !labels.is_empty() {
+                assert!(catch_funclet.is_none());
+                bx.callbr(fty, None, None, v, inputs, dest.unwrap(), labels, None, None)
+            } else if let Some((catch, funclet)) = catch_funclet {
+                bx.invoke(fty, None, None, v, inputs, dest.unwrap(), catch, funclet, None)
+            } else {
+                bx.call(fty, None, None, v, inputs, None, None)
+            };
+
+            // Store mark in a metadata node so we can map LLVM errors
+            // back to source locations. See #17552.
+            let key = "srcloc";
+            let kind = llvm::LLVMGetMDKindIDInContext(
+                bx.llcx,
+                key.as_ptr() as *const c_char,
+                key.len() as c_uint,
+            );
+
+            // srcloc contains one integer for each line of assembly code.
+            // Unfortunately this isn't enough to encode a full span so instead
+            // we just encode the start position of each line.
+            // FIXME: Figure out a way to pass the entire line spans.
+            let mut srcloc = vec![];
+            if dia == llvm::AsmDialect::Intel && line_spans.len() > 1 {
+                // LLVM inserts an extra line to add the ".intel_syntax", so add
+                // a dummy srcloc entry for it.
+                //
+                // Don't do this if we only have 1 line span since that may be
+                // due to the asm template string coming from a macro. LLVM will
+                // default to the first srcloc for lines that don't have an
+                // associated srcloc.
+                srcloc.push(bx.const_i32(0));
+            }
+            srcloc.extend(line_spans.iter().map(|span| bx.const_i32(span.lo().to_u32() as i32)));
+            let md = llvm::LLVMMDNodeInContext(bx.llcx, srcloc.as_ptr(), srcloc.len() as u32);
+            llvm::LLVMSetMetadata(call, kind, md);
+
+            Some(call)
+        } else {
+            // LLVM has detected an issue with our constraints, bail out
+            None
+        }
+    }
+}
+
+/// If the register is an xmm/ymm/zmm register then return its index.
+fn xmm_reg_index(reg: InlineAsmReg) -> Option<u32> {
+    match reg {
+        InlineAsmReg::X86(reg)
+            if reg as u32 >= X86InlineAsmReg::xmm0 as u32
+                && reg as u32 <= X86InlineAsmReg::xmm15 as u32 =>
+        {
+            Some(reg as u32 - X86InlineAsmReg::xmm0 as u32)
+        }
+        InlineAsmReg::X86(reg)
+            if reg as u32 >= X86InlineAsmReg::ymm0 as u32
+                && reg as u32 <= X86InlineAsmReg::ymm15 as u32 =>
+        {
+            Some(reg as u32 - X86InlineAsmReg::ymm0 as u32)
+        }
+        InlineAsmReg::X86(reg)
+            if reg as u32 >= X86InlineAsmReg::zmm0 as u32
+                && reg as u32 <= X86InlineAsmReg::zmm31 as u32 =>
+        {
+            Some(reg as u32 - X86InlineAsmReg::zmm0 as u32)
+        }
+        _ => None,
+    }
+}
+
+/// If the register is an AArch64 integer register then return its index.
+fn a64_reg_index(reg: InlineAsmReg) -> Option<u32> {
+    match reg {
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x0) => Some(0),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x1) => Some(1),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x2) => Some(2),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x3) => Some(3),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x4) => Some(4),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x5) => Some(5),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x6) => Some(6),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x7) => Some(7),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x8) => Some(8),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x9) => Some(9),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x10) => Some(10),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x11) => Some(11),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x12) => Some(12),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x13) => Some(13),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x14) => Some(14),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x15) => Some(15),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x16) => Some(16),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x17) => Some(17),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x18) => Some(18),
+        // x19 is reserved
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x20) => Some(20),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x21) => Some(21),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x22) => Some(22),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x23) => Some(23),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x24) => Some(24),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x25) => Some(25),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x26) => Some(26),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x27) => Some(27),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x28) => Some(28),
+        // x29 is reserved
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x30) => Some(30),
+        _ => None,
+    }
+}
+
+/// If the register is an AArch64 vector register then return its index.
+fn a64_vreg_index(reg: InlineAsmReg) -> Option<u32> {
+    match reg {
+        InlineAsmReg::AArch64(reg)
+            if reg as u32 >= AArch64InlineAsmReg::v0 as u32
+                && reg as u32 <= AArch64InlineAsmReg::v31 as u32 =>
+        {
+            Some(reg as u32 - AArch64InlineAsmReg::v0 as u32)
+        }
+        _ => None,
+    }
+}
+
+/// Converts a register class to an LLVM constraint code.
+fn reg_to_llvm(reg: InlineAsmRegOrRegClass, layout: Option<&TyAndLayout<'_>>) -> String {
+    match reg {
+        // For vector registers LLVM wants the register name to match the type size.
+        InlineAsmRegOrRegClass::Reg(reg) => {
+            if let Some(idx) = xmm_reg_index(reg) {
+                let class = if let Some(layout) = layout {
+                    match layout.size.bytes() {
+                        64 => 'z',
+                        32 => 'y',
+                        _ => 'x',
+                    }
+                } else {
+                    // We use f32 as the type for discarded outputs
+                    'x'
+                };
+                format!("{{{}mm{}}}", class, idx)
+            } else if let Some(idx) = a64_reg_index(reg) {
+                let class = if let Some(layout) = layout {
+                    match layout.size.bytes() {
+                        8 => 'x',
+                        _ => 'w',
+                    }
+                } else {
+                    // We use i32 as the type for discarded outputs
+                    'w'
+                };
+                if class == 'x' && reg == InlineAsmReg::AArch64(AArch64InlineAsmReg::x30) {
+                    // LLVM doesn't recognize x30. use lr instead.
+                    "{lr}".to_string()
+                } else {
+                    format!("{{{}{}}}", class, idx)
+                }
+            } else if let Some(idx) = a64_vreg_index(reg) {
+                let class = if let Some(layout) = layout {
+                    match layout.size.bytes() {
+                        16 => 'q',
+                        8 => 'd',
+                        4 => 's',
+                        2 => 'h',
+                        1 => 'd', // We fixup i8 to i8x8
+                        _ => unreachable!(),
+                    }
+                } else {
+                    // We use i64x2 as the type for discarded outputs
+                    'q'
+                };
+                format!("{{{}{}}}", class, idx)
+            } else if reg == InlineAsmReg::Arm(ArmInlineAsmReg::r14) {
+                // LLVM doesn't recognize r14
+                "{lr}".to_string()
+            } else {
+                format!("{{{}}}", reg.name())
+            }
+        }
+        // The constraints can be retrieved from
+        // https://llvm.org/docs/LangRef.html#supported-constraint-code-list
+        InlineAsmRegOrRegClass::RegClass(reg) => match reg {
+            InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg) => "w",
+            InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16) => "x",
+            InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::preg) => {
+                unreachable!("clobber-only")
+            }
+            InlineAsmRegClass::Arm(ArmInlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg)
+            | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low16)
+            | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low8) => "t",
+            InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg_low16)
+            | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low8)
+            | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low4) => "x",
+            InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg)
+            | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg) => "w",
+            InlineAsmRegClass::Hexagon(HexagonInlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::LoongArch(LoongArchInlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::LoongArch(LoongArchInlineAsmRegClass::freg) => "f",
+            InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::Mips(MipsInlineAsmRegClass::freg) => "f",
+            InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg16) => "h",
+            InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg32) => "r",
+            InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg64) => "l",
+            InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::reg_nonzero) => "b",
+            InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::freg) => "f",
+            InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::cr)
+            | InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::xer) => {
+                unreachable!("clobber-only")
+            }
+            InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::freg) => "f",
+            InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::vreg) => {
+                unreachable!("clobber-only")
+            }
+            InlineAsmRegClass::X86(X86InlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd) => "Q",
+            InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_byte) => "q",
+            InlineAsmRegClass::X86(X86InlineAsmRegClass::xmm_reg)
+            | InlineAsmRegClass::X86(X86InlineAsmRegClass::ymm_reg) => "x",
+            InlineAsmRegClass::X86(X86InlineAsmRegClass::zmm_reg) => "v",
+            InlineAsmRegClass::X86(X86InlineAsmRegClass::kreg) => "^Yk",
+            InlineAsmRegClass::X86(
+                X86InlineAsmRegClass::x87_reg
+                | X86InlineAsmRegClass::mmx_reg
+                | X86InlineAsmRegClass::kreg0
+                | X86InlineAsmRegClass::tmm_reg,
+            ) => unreachable!("clobber-only"),
+            InlineAsmRegClass::Wasm(WasmInlineAsmRegClass::local) => "r",
+            InlineAsmRegClass::Bpf(BpfInlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::Bpf(BpfInlineAsmRegClass::wreg) => "w",
+            InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_upper) => "d",
+            InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_pair) => "r",
+            InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_iw) => "w",
+            InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_ptr) => "e",
+            InlineAsmRegClass::S390x(S390xInlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::S390x(S390xInlineAsmRegClass::reg_addr) => "a",
+            InlineAsmRegClass::S390x(S390xInlineAsmRegClass::freg) => "f",
+            InlineAsmRegClass::Msp430(Msp430InlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_addr) => "a",
+            InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_data) => "d",
+            InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::reg) => "r",
+            InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::freg) => "f",
+            InlineAsmRegClass::SpirV(SpirVInlineAsmRegClass::reg) => {
+                bug!("LLVM backend does not support SPIR-V")
+            }
+            InlineAsmRegClass::Err => unreachable!(),
+        }
+        .to_string(),
+    }
+}
+
+/// Converts a modifier into LLVM's equivalent modifier.
+fn modifier_to_llvm(
+    arch: InlineAsmArch,
+    reg: InlineAsmRegClass,
+    modifier: Option<char>,
+) -> Option<char> {
+    // The modifiers can be retrieved from
+    // https://llvm.org/docs/LangRef.html#asm-template-argument-modifiers
+    match reg {
+        InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::reg) => modifier,
+        InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg)
+        | InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16) => {
+            if modifier == Some('v') { None } else { modifier }
+        }
+        InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::preg) => {
+            unreachable!("clobber-only")
+        }
+        InlineAsmRegClass::Arm(ArmInlineAsmRegClass::reg) => None,
+        InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg)
+        | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg_low16) => None,
+        InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg)
+        | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low16)
+        | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low8) => Some('P'),
+        InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg)
+        | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low8)
+        | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low4) => {
+            if modifier.is_none() {
+                Some('q')
+            } else {
+                modifier
+            }
+        }
+        InlineAsmRegClass::Hexagon(_) => None,
+        InlineAsmRegClass::LoongArch(_) => None,
+        InlineAsmRegClass::Mips(_) => None,
+        InlineAsmRegClass::Nvptx(_) => None,
+        InlineAsmRegClass::PowerPC(_) => None,
+        InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::reg)
+        | InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::freg) => None,
+        InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::vreg) => {
+            unreachable!("clobber-only")
+        }
+        InlineAsmRegClass::X86(X86InlineAsmRegClass::reg)
+        | InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd) => match modifier {
+            None if arch == InlineAsmArch::X86_64 => Some('q'),
+            None => Some('k'),
+            Some('l') => Some('b'),
+            Some('h') => Some('h'),
+            Some('x') => Some('w'),
+            Some('e') => Some('k'),
+            Some('r') => Some('q'),
+            _ => unreachable!(),
+        },
+        InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_byte) => None,
+        InlineAsmRegClass::X86(reg @ X86InlineAsmRegClass::xmm_reg)
+        | InlineAsmRegClass::X86(reg @ X86InlineAsmRegClass::ymm_reg)
+        | InlineAsmRegClass::X86(reg @ X86InlineAsmRegClass::zmm_reg) => match (reg, modifier) {
+            (X86InlineAsmRegClass::xmm_reg, None) => Some('x'),
+            (X86InlineAsmRegClass::ymm_reg, None) => Some('t'),
+            (X86InlineAsmRegClass::zmm_reg, None) => Some('g'),
+            (_, Some('x')) => Some('x'),
+            (_, Some('y')) => Some('t'),
+            (_, Some('z')) => Some('g'),
+            _ => unreachable!(),
+        },
+        InlineAsmRegClass::X86(X86InlineAsmRegClass::kreg) => None,
+        InlineAsmRegClass::X86(
+            X86InlineAsmRegClass::x87_reg
+            | X86InlineAsmRegClass::mmx_reg
+            | X86InlineAsmRegClass::kreg0
+            | X86InlineAsmRegClass::tmm_reg,
+        ) => {
+            unreachable!("clobber-only")
+        }
+        InlineAsmRegClass::Wasm(WasmInlineAsmRegClass::local) => None,
+        InlineAsmRegClass::Bpf(_) => None,
+        InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_pair)
+        | InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_iw)
+        | InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_ptr) => match modifier {
+            Some('h') => Some('B'),
+            Some('l') => Some('A'),
+            _ => None,
+        },
+        InlineAsmRegClass::Avr(_) => None,
+        InlineAsmRegClass::S390x(_) => None,
+        InlineAsmRegClass::Msp430(_) => None,
+        InlineAsmRegClass::SpirV(SpirVInlineAsmRegClass::reg) => {
+            bug!("LLVM backend does not support SPIR-V")
+        }
+        InlineAsmRegClass::M68k(_) => None,
+        InlineAsmRegClass::CSKY(_) => None,
+        InlineAsmRegClass::Err => unreachable!(),
+    }
+}
+
+/// Type to use for outputs that are discarded. It doesn't really matter what
+/// the type is, as long as it is valid for the constraint code.
+fn dummy_output_type<'ll>(cx: &CodegenCx<'ll, '_>, reg: InlineAsmRegClass) -> &'ll Type {
+    match reg {
+        InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::reg) => cx.type_i32(),
+        InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg)
+        | InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16) => {
+            cx.type_vector(cx.type_i64(), 2)
+        }
+        InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::preg) => {
+            unreachable!("clobber-only")
+        }
+        InlineAsmRegClass::Arm(ArmInlineAsmRegClass::reg) => cx.type_i32(),
+        InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg)
+        | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg_low16) => cx.type_f32(),
+        InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg)
+        | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low16)
+        | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low8) => cx.type_f64(),
+        InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg)
+        | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low8)
+        | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low4) => {
+            cx.type_vector(cx.type_i64(), 2)
+        }
+        InlineAsmRegClass::Hexagon(HexagonInlineAsmRegClass::reg) => cx.type_i32(),
+        InlineAsmRegClass::LoongArch(LoongArchInlineAsmRegClass::reg) => cx.type_i32(),
+        InlineAsmRegClass::LoongArch(LoongArchInlineAsmRegClass::freg) => cx.type_f32(),
+        InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg) => cx.type_i32(),
+        InlineAsmRegClass::Mips(MipsInlineAsmRegClass::freg) => cx.type_f32(),
+        InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg16) => cx.type_i16(),
+        InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg32) => cx.type_i32(),
+        InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg64) => cx.type_i64(),
+        InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::reg) => cx.type_i32(),
+        InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::reg_nonzero) => cx.type_i32(),
+        InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::freg) => cx.type_f64(),
+        InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::cr)
+        | InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::xer) => {
+            unreachable!("clobber-only")
+        }
+        InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::reg) => cx.type_i32(),
+        InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::freg) => cx.type_f32(),
+        InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::vreg) => {
+            unreachable!("clobber-only")
+        }
+        InlineAsmRegClass::X86(X86InlineAsmRegClass::reg)
+        | InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd) => cx.type_i32(),
+        InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_byte) => cx.type_i8(),
+        InlineAsmRegClass::X86(X86InlineAsmRegClass::xmm_reg)
+        | InlineAsmRegClass::X86(X86InlineAsmRegClass::ymm_reg)
+        | InlineAsmRegClass::X86(X86InlineAsmRegClass::zmm_reg) => cx.type_f32(),
+        InlineAsmRegClass::X86(X86InlineAsmRegClass::kreg) => cx.type_i16(),
+        InlineAsmRegClass::X86(
+            X86InlineAsmRegClass::x87_reg
+            | X86InlineAsmRegClass::mmx_reg
+            | X86InlineAsmRegClass::kreg0
+            | X86InlineAsmRegClass::tmm_reg,
+        ) => {
+            unreachable!("clobber-only")
+        }
+        InlineAsmRegClass::Wasm(WasmInlineAsmRegClass::local) => cx.type_i32(),
+        InlineAsmRegClass::Bpf(BpfInlineAsmRegClass::reg) => cx.type_i64(),
+        InlineAsmRegClass::Bpf(BpfInlineAsmRegClass::wreg) => cx.type_i32(),
+        InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg) => cx.type_i8(),
+        InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_upper) => cx.type_i8(),
+        InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_pair) => cx.type_i16(),
+        InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_iw) => cx.type_i16(),
+        InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_ptr) => cx.type_i16(),
+        InlineAsmRegClass::S390x(
+            S390xInlineAsmRegClass::reg | S390xInlineAsmRegClass::reg_addr,
+        ) => cx.type_i32(),
+        InlineAsmRegClass::S390x(S390xInlineAsmRegClass::freg) => cx.type_f64(),
+        InlineAsmRegClass::Msp430(Msp430InlineAsmRegClass::reg) => cx.type_i16(),
+        InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg) => cx.type_i32(),
+        InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_addr) => cx.type_i32(),
+        InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_data) => cx.type_i32(),
+        InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::reg) => cx.type_i32(),
+        InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::freg) => cx.type_f32(),
+        InlineAsmRegClass::SpirV(SpirVInlineAsmRegClass::reg) => {
+            bug!("LLVM backend does not support SPIR-V")
+        }
+        InlineAsmRegClass::Err => unreachable!(),
+    }
+}
+
+/// Helper function to get the LLVM type for a Scalar. Pointers are returned as
+/// the equivalent integer type.
+fn llvm_asm_scalar_type<'ll>(cx: &CodegenCx<'ll, '_>, scalar: Scalar) -> &'ll Type {
+    let dl = &cx.tcx.data_layout;
+    match scalar.primitive() {
+        Primitive::Int(Integer::I8, _) => cx.type_i8(),
+        Primitive::Int(Integer::I16, _) => cx.type_i16(),
+        Primitive::Int(Integer::I32, _) => cx.type_i32(),
+        Primitive::Int(Integer::I64, _) => cx.type_i64(),
+        Primitive::Float(Float::F32) => cx.type_f32(),
+        Primitive::Float(Float::F64) => cx.type_f64(),
+        // FIXME(erikdesjardins): handle non-default addrspace ptr sizes
+        Primitive::Pointer(_) => cx.type_from_integer(dl.ptr_sized_integer()),
+        _ => unreachable!(),
+    }
+}
+
+fn any_target_feature_enabled(
+    cx: &CodegenCx<'_, '_>,
+    instance: Instance<'_>,
+    features: &[Symbol],
+) -> bool {
+    let enabled = cx.tcx.asm_target_features(instance.def_id());
+    features.iter().any(|feat| enabled.contains(feat))
+}
+
+/// Fix up an input value to work around LLVM bugs.
+fn llvm_fixup_input<'ll, 'tcx>(
+    bx: &mut Builder<'_, 'll, 'tcx>,
+    mut value: &'ll Value,
+    reg: InlineAsmRegClass,
+    layout: &TyAndLayout<'tcx>,
+    instance: Instance<'_>,
+) -> &'ll Value {
+    let dl = &bx.tcx.data_layout;
+    match (reg, layout.abi) {
+        (InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg), Abi::Scalar(s)) => {
+            if let Primitive::Int(Integer::I8, _) = s.primitive() {
+                let vec_ty = bx.cx.type_vector(bx.cx.type_i8(), 8);
+                bx.insert_element(bx.const_undef(vec_ty), value, bx.const_i32(0))
+            } else {
+                value
+            }
+        }
+        (InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16), Abi::Scalar(s)) => {
+            let elem_ty = llvm_asm_scalar_type(bx.cx, s);
+            let count = 16 / layout.size.bytes();
+            let vec_ty = bx.cx.type_vector(elem_ty, count);
+            // FIXME(erikdesjardins): handle non-default addrspace ptr sizes
+            if let Primitive::Pointer(_) = s.primitive() {
+                let t = bx.type_from_integer(dl.ptr_sized_integer());
+                value = bx.ptrtoint(value, t);
+            }
+            bx.insert_element(bx.const_undef(vec_ty), value, bx.const_i32(0))
+        }
+        (
+            InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16),
+            Abi::Vector { element, count },
+        ) if layout.size.bytes() == 8 => {
+            let elem_ty = llvm_asm_scalar_type(bx.cx, element);
+            let vec_ty = bx.cx.type_vector(elem_ty, count);
+            let indices: Vec<_> = (0..count * 2).map(|x| bx.const_i32(x as i32)).collect();
+            bx.shuffle_vector(value, bx.const_undef(vec_ty), bx.const_vector(&indices))
+        }
+        (InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd), Abi::Scalar(s))
+            if s.primitive() == Primitive::Float(Float::F64) =>
+        {
+            bx.bitcast(value, bx.cx.type_i64())
+        }
+        (
+            InlineAsmRegClass::X86(X86InlineAsmRegClass::xmm_reg | X86InlineAsmRegClass::zmm_reg),
+            Abi::Vector { .. },
+        ) if layout.size.bytes() == 64 => bx.bitcast(value, bx.cx.type_vector(bx.cx.type_f64(), 8)),
+        (
+            InlineAsmRegClass::X86(
+                X86InlineAsmRegClass::xmm_reg
+                | X86InlineAsmRegClass::ymm_reg
+                | X86InlineAsmRegClass::zmm_reg,
+            ),
+            Abi::Scalar(s),
+        ) if bx.sess().asm_arch == Some(InlineAsmArch::X86)
+            && s.primitive() == Primitive::Float(Float::F128) =>
+        {
+            bx.bitcast(value, bx.type_vector(bx.type_i32(), 4))
+        }
+        (
+            InlineAsmRegClass::X86(
+                X86InlineAsmRegClass::xmm_reg
+                | X86InlineAsmRegClass::ymm_reg
+                | X86InlineAsmRegClass::zmm_reg,
+            ),
+            Abi::Scalar(s),
+        ) if s.primitive() == Primitive::Float(Float::F16) => {
+            let value = bx.insert_element(
+                bx.const_undef(bx.type_vector(bx.type_f16(), 8)),
+                value,
+                bx.const_usize(0),
+            );
+            bx.bitcast(value, bx.type_vector(bx.type_i16(), 8))
+        }
+        (
+            InlineAsmRegClass::X86(
+                X86InlineAsmRegClass::xmm_reg
+                | X86InlineAsmRegClass::ymm_reg
+                | X86InlineAsmRegClass::zmm_reg,
+            ),
+            Abi::Vector { element, count: count @ (8 | 16) },
+        ) if element.primitive() == Primitive::Float(Float::F16) => {
+            bx.bitcast(value, bx.type_vector(bx.type_i16(), count))
+        }
+        (
+            InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg | ArmInlineAsmRegClass::sreg_low16),
+            Abi::Scalar(s),
+        ) => {
+            if let Primitive::Int(Integer::I32, _) = s.primitive() {
+                bx.bitcast(value, bx.cx.type_f32())
+            } else {
+                value
+            }
+        }
+        (
+            InlineAsmRegClass::Arm(
+                ArmInlineAsmRegClass::dreg
+                | ArmInlineAsmRegClass::dreg_low8
+                | ArmInlineAsmRegClass::dreg_low16,
+            ),
+            Abi::Scalar(s),
+        ) => {
+            if let Primitive::Int(Integer::I64, _) = s.primitive() {
+                bx.bitcast(value, bx.cx.type_f64())
+            } else {
+                value
+            }
+        }
+        (
+            InlineAsmRegClass::Arm(
+                ArmInlineAsmRegClass::dreg
+                | ArmInlineAsmRegClass::dreg_low8
+                | ArmInlineAsmRegClass::dreg_low16
+                | ArmInlineAsmRegClass::qreg
+                | ArmInlineAsmRegClass::qreg_low4
+                | ArmInlineAsmRegClass::qreg_low8,
+            ),
+            Abi::Vector { element, count: count @ (4 | 8) },
+        ) if element.primitive() == Primitive::Float(Float::F16) => {
+            bx.bitcast(value, bx.type_vector(bx.type_i16(), count))
+        }
+        (InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg), Abi::Scalar(s)) => {
+            match s.primitive() {
+                // MIPS only supports register-length arithmetics.
+                Primitive::Int(Integer::I8 | Integer::I16, _) => bx.zext(value, bx.cx.type_i32()),
+                Primitive::Float(Float::F32) => bx.bitcast(value, bx.cx.type_i32()),
+                Primitive::Float(Float::F64) => bx.bitcast(value, bx.cx.type_i64()),
+                _ => value,
+            }
+        }
+        (InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::freg), Abi::Scalar(s))
+            if s.primitive() == Primitive::Float(Float::F16)
+                && !any_target_feature_enabled(bx, instance, &[sym::zfhmin, sym::zfh]) =>
+        {
+            // Smaller floats are always "NaN-boxed" inside larger floats on RISC-V.
+            let value = bx.bitcast(value, bx.type_i16());
+            let value = bx.zext(value, bx.type_i32());
+            let value = bx.or(value, bx.const_u32(0xFFFF_0000));
+            bx.bitcast(value, bx.type_f32())
+        }
+        _ => value,
+    }
+}
+
+/// Fix up an output value to work around LLVM bugs.
+fn llvm_fixup_output<'ll, 'tcx>(
+    bx: &mut Builder<'_, 'll, 'tcx>,
+    mut value: &'ll Value,
+    reg: InlineAsmRegClass,
+    layout: &TyAndLayout<'tcx>,
+    instance: Instance<'_>,
+) -> &'ll Value {
+    match (reg, layout.abi) {
+        (InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg), Abi::Scalar(s)) => {
+            if let Primitive::Int(Integer::I8, _) = s.primitive() {
+                bx.extract_element(value, bx.const_i32(0))
+            } else {
+                value
+            }
+        }
+        (InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16), Abi::Scalar(s)) => {
+            value = bx.extract_element(value, bx.const_i32(0));
+            if let Primitive::Pointer(_) = s.primitive() {
+                value = bx.inttoptr(value, layout.llvm_type(bx.cx));
+            }
+            value
+        }
+        (
+            InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16),
+            Abi::Vector { element, count },
+        ) if layout.size.bytes() == 8 => {
+            let elem_ty = llvm_asm_scalar_type(bx.cx, element);
+            let vec_ty = bx.cx.type_vector(elem_ty, count * 2);
+            let indices: Vec<_> = (0..count).map(|x| bx.const_i32(x as i32)).collect();
+            bx.shuffle_vector(value, bx.const_undef(vec_ty), bx.const_vector(&indices))
+        }
+        (InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd), Abi::Scalar(s))
+            if s.primitive() == Primitive::Float(Float::F64) =>
+        {
+            bx.bitcast(value, bx.cx.type_f64())
+        }
+        (
+            InlineAsmRegClass::X86(X86InlineAsmRegClass::xmm_reg | X86InlineAsmRegClass::zmm_reg),
+            Abi::Vector { .. },
+        ) if layout.size.bytes() == 64 => bx.bitcast(value, layout.llvm_type(bx.cx)),
+        (
+            InlineAsmRegClass::X86(
+                X86InlineAsmRegClass::xmm_reg
+                | X86InlineAsmRegClass::ymm_reg
+                | X86InlineAsmRegClass::zmm_reg,
+            ),
+            Abi::Scalar(s),
+        ) if bx.sess().asm_arch == Some(InlineAsmArch::X86)
+            && s.primitive() == Primitive::Float(Float::F128) =>
+        {
+            bx.bitcast(value, bx.type_f128())
+        }
+        (
+            InlineAsmRegClass::X86(
+                X86InlineAsmRegClass::xmm_reg
+                | X86InlineAsmRegClass::ymm_reg
+                | X86InlineAsmRegClass::zmm_reg,
+            ),
+            Abi::Scalar(s),
+        ) if s.primitive() == Primitive::Float(Float::F16) => {
+            let value = bx.bitcast(value, bx.type_vector(bx.type_f16(), 8));
+            bx.extract_element(value, bx.const_usize(0))
+        }
+        (
+            InlineAsmRegClass::X86(
+                X86InlineAsmRegClass::xmm_reg
+                | X86InlineAsmRegClass::ymm_reg
+                | X86InlineAsmRegClass::zmm_reg,
+            ),
+            Abi::Vector { element, count: count @ (8 | 16) },
+        ) if element.primitive() == Primitive::Float(Float::F16) => {
+            bx.bitcast(value, bx.type_vector(bx.type_f16(), count))
+        }
+        (
+            InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg | ArmInlineAsmRegClass::sreg_low16),
+            Abi::Scalar(s),
+        ) => {
+            if let Primitive::Int(Integer::I32, _) = s.primitive() {
+                bx.bitcast(value, bx.cx.type_i32())
+            } else {
+                value
+            }
+        }
+        (
+            InlineAsmRegClass::Arm(
+                ArmInlineAsmRegClass::dreg
+                | ArmInlineAsmRegClass::dreg_low8
+                | ArmInlineAsmRegClass::dreg_low16,
+            ),
+            Abi::Scalar(s),
+        ) => {
+            if let Primitive::Int(Integer::I64, _) = s.primitive() {
+                bx.bitcast(value, bx.cx.type_i64())
+            } else {
+                value
+            }
+        }
+        (
+            InlineAsmRegClass::Arm(
+                ArmInlineAsmRegClass::dreg
+                | ArmInlineAsmRegClass::dreg_low8
+                | ArmInlineAsmRegClass::dreg_low16
+                | ArmInlineAsmRegClass::qreg
+                | ArmInlineAsmRegClass::qreg_low4
+                | ArmInlineAsmRegClass::qreg_low8,
+            ),
+            Abi::Vector { element, count: count @ (4 | 8) },
+        ) if element.primitive() == Primitive::Float(Float::F16) => {
+            bx.bitcast(value, bx.type_vector(bx.type_f16(), count))
+        }
+        (InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg), Abi::Scalar(s)) => {
+            match s.primitive() {
+                // MIPS only supports register-length arithmetics.
+                Primitive::Int(Integer::I8, _) => bx.trunc(value, bx.cx.type_i8()),
+                Primitive::Int(Integer::I16, _) => bx.trunc(value, bx.cx.type_i16()),
+                Primitive::Float(Float::F32) => bx.bitcast(value, bx.cx.type_f32()),
+                Primitive::Float(Float::F64) => bx.bitcast(value, bx.cx.type_f64()),
+                _ => value,
+            }
+        }
+        (InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::freg), Abi::Scalar(s))
+            if s.primitive() == Primitive::Float(Float::F16)
+                && !any_target_feature_enabled(bx, instance, &[sym::zfhmin, sym::zfh]) =>
+        {
+            let value = bx.bitcast(value, bx.type_i32());
+            let value = bx.trunc(value, bx.type_i16());
+            bx.bitcast(value, bx.type_f16())
+        }
+        _ => value,
+    }
+}
+
+/// Output type to use for llvm_fixup_output.
+fn llvm_fixup_output_type<'ll, 'tcx>(
+    cx: &CodegenCx<'ll, 'tcx>,
+    reg: InlineAsmRegClass,
+    layout: &TyAndLayout<'tcx>,
+    instance: Instance<'_>,
+) -> &'ll Type {
+    match (reg, layout.abi) {
+        (InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg), Abi::Scalar(s)) => {
+            if let Primitive::Int(Integer::I8, _) = s.primitive() {
+                cx.type_vector(cx.type_i8(), 8)
+            } else {
+                layout.llvm_type(cx)
+            }
+        }
+        (InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16), Abi::Scalar(s)) => {
+            let elem_ty = llvm_asm_scalar_type(cx, s);
+            let count = 16 / layout.size.bytes();
+            cx.type_vector(elem_ty, count)
+        }
+        (
+            InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16),
+            Abi::Vector { element, count },
+        ) if layout.size.bytes() == 8 => {
+            let elem_ty = llvm_asm_scalar_type(cx, element);
+            cx.type_vector(elem_ty, count * 2)
+        }
+        (InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd), Abi::Scalar(s))
+            if s.primitive() == Primitive::Float(Float::F64) =>
+        {
+            cx.type_i64()
+        }
+        (
+            InlineAsmRegClass::X86(X86InlineAsmRegClass::xmm_reg | X86InlineAsmRegClass::zmm_reg),
+            Abi::Vector { .. },
+        ) if layout.size.bytes() == 64 => cx.type_vector(cx.type_f64(), 8),
+        (
+            InlineAsmRegClass::X86(
+                X86InlineAsmRegClass::xmm_reg
+                | X86InlineAsmRegClass::ymm_reg
+                | X86InlineAsmRegClass::zmm_reg,
+            ),
+            Abi::Scalar(s),
+        ) if cx.sess().asm_arch == Some(InlineAsmArch::X86)
+            && s.primitive() == Primitive::Float(Float::F128) =>
+        {
+            cx.type_vector(cx.type_i32(), 4)
+        }
+        (
+            InlineAsmRegClass::X86(
+                X86InlineAsmRegClass::xmm_reg
+                | X86InlineAsmRegClass::ymm_reg
+                | X86InlineAsmRegClass::zmm_reg,
+            ),
+            Abi::Scalar(s),
+        ) if s.primitive() == Primitive::Float(Float::F16) => cx.type_vector(cx.type_i16(), 8),
+        (
+            InlineAsmRegClass::X86(
+                X86InlineAsmRegClass::xmm_reg
+                | X86InlineAsmRegClass::ymm_reg
+                | X86InlineAsmRegClass::zmm_reg,
+            ),
+            Abi::Vector { element, count: count @ (8 | 16) },
+        ) if element.primitive() == Primitive::Float(Float::F16) => {
+            cx.type_vector(cx.type_i16(), count)
+        }
+        (
+            InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg | ArmInlineAsmRegClass::sreg_low16),
+            Abi::Scalar(s),
+        ) => {
+            if let Primitive::Int(Integer::I32, _) = s.primitive() {
+                cx.type_f32()
+            } else {
+                layout.llvm_type(cx)
+            }
+        }
+        (
+            InlineAsmRegClass::Arm(
+                ArmInlineAsmRegClass::dreg
+                | ArmInlineAsmRegClass::dreg_low8
+                | ArmInlineAsmRegClass::dreg_low16,
+            ),
+            Abi::Scalar(s),
+        ) => {
+            if let Primitive::Int(Integer::I64, _) = s.primitive() {
+                cx.type_f64()
+            } else {
+                layout.llvm_type(cx)
+            }
+        }
+        (
+            InlineAsmRegClass::Arm(
+                ArmInlineAsmRegClass::dreg
+                | ArmInlineAsmRegClass::dreg_low8
+                | ArmInlineAsmRegClass::dreg_low16
+                | ArmInlineAsmRegClass::qreg
+                | ArmInlineAsmRegClass::qreg_low4
+                | ArmInlineAsmRegClass::qreg_low8,
+            ),
+            Abi::Vector { element, count: count @ (4 | 8) },
+        ) if element.primitive() == Primitive::Float(Float::F16) => {
+            cx.type_vector(cx.type_i16(), count)
+        }
+        (InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg), Abi::Scalar(s)) => {
+            match s.primitive() {
+                // MIPS only supports register-length arithmetics.
+                Primitive::Int(Integer::I8 | Integer::I16, _) => cx.type_i32(),
+                Primitive::Float(Float::F32) => cx.type_i32(),
+                Primitive::Float(Float::F64) => cx.type_i64(),
+                _ => layout.llvm_type(cx),
+            }
+        }
+        (InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::freg), Abi::Scalar(s))
+            if s.primitive() == Primitive::Float(Float::F16)
+                && !any_target_feature_enabled(cx, instance, &[sym::zfhmin, sym::zfh]) =>
+        {
+            cx.type_f32()
+        }
+        _ => layout.llvm_type(cx),
+    }
+}