Update the minimum external LLVM to 19

8 files changed, 47 insertions, 233 deletions

diff --git a/compiler/rustc_codegen_llvm/src/abi.rs b/compiler/rustc_codegen_llvm/src/abi.rs
index 71059338151..8294e29d07d 100644
--- a/compiler/rustc_codegen_llvm/src/abi.rs
+++ b/compiler/rustc_codegen_llvm/src/abi.rs
@@ -17,14 +17,13 @@ use rustc_target::callconv::{
 use rustc_target::spec::SanitizerSet;
 use smallvec::SmallVec;
 
-use crate::attributes::llfn_attrs_from_instance;
+use crate::attributes::{self, llfn_attrs_from_instance};
 use crate::builder::Builder;
 use crate::context::CodegenCx;
 use crate::llvm::{self, Attribute, AttributePlace};
 use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
-use crate::{attributes, llvm_util};
 
 trait ArgAttributesExt {
     fn apply_attrs_to_llfn(&self, idx: AttributePlace, cx: &CodegenCx<'_, '_>, llfn: &Value);
@@ -437,7 +436,6 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
 
         let apply_range_attr = |idx: AttributePlace, scalar: rustc_abi::Scalar| {
             if cx.sess().opts.optimize != config::OptLevel::No
-                && llvm_util::get_version() >= (19, 0, 0)
                 && matches!(scalar.primitive(), Primitive::Int(..))
                 // If the value is a boolean, the range is 0..2 and that ultimately
                 // become 0..0 when the type becomes i1, which would be rejected
@@ -571,19 +569,6 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
             }
             _ => {}
         }
-        if bx.cx.sess().opts.optimize != config::OptLevel::No
-                && llvm_util::get_version() < (19, 0, 0)
-                && let BackendRepr::Scalar(scalar) = self.ret.layout.backend_repr
-                && matches!(scalar.primitive(), Primitive::Int(..))
-                // If the value is a boolean, the range is 0..2 and that ultimately
-                // become 0..0 when the type becomes i1, which would be rejected
-                // by the LLVM verifier.
-                && !scalar.is_bool()
-                // LLVM also rejects full range.
-                && !scalar.is_always_valid(bx)
-        {
-            bx.range_metadata(callsite, scalar.valid_range(bx));
-        }
         for arg in self.args.iter() {
             match &arg.mode {
                 PassMode::Ignore => {}
diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs
index 3d7afa17bdf..e8c42d16733 100644
--- a/compiler/rustc_codegen_llvm/src/attributes.rs
+++ b/compiler/rustc_codegen_llvm/src/attributes.rs
@@ -407,30 +407,28 @@ pub(crate) fn llfn_attrs_from_instance<'ll, 'tcx>(
         // Do not set sanitizer attributes for naked functions.
         to_add.extend(sanitize_attrs(cx, codegen_fn_attrs.no_sanitize));
 
-        if llvm_util::get_version() >= (19, 0, 0) {
-            // For non-naked functions, set branch protection attributes on aarch64.
-            if let Some(BranchProtection { bti, pac_ret }) =
-                cx.sess().opts.unstable_opts.branch_protection
-            {
-                assert!(cx.sess().target.arch == "aarch64");
-                if bti {
-                    to_add.push(llvm::CreateAttrString(cx.llcx, "branch-target-enforcement"));
-                }
-                if let Some(PacRet { leaf, pc, key }) = pac_ret {
-                    if pc {
-                        to_add.push(llvm::CreateAttrString(cx.llcx, "branch-protection-pauth-lr"));
-                    }
-                    to_add.push(llvm::CreateAttrStringValue(
-                        cx.llcx,
-                        "sign-return-address",
-                        if leaf { "all" } else { "non-leaf" },
-                    ));
-                    to_add.push(llvm::CreateAttrStringValue(
-                        cx.llcx,
-                        "sign-return-address-key",
-                        if key == PAuthKey::A { "a_key" } else { "b_key" },
-                    ));
+        // For non-naked functions, set branch protection attributes on aarch64.
+        if let Some(BranchProtection { bti, pac_ret }) =
+            cx.sess().opts.unstable_opts.branch_protection
+        {
+            assert!(cx.sess().target.arch == "aarch64");
+            if bti {
+                to_add.push(llvm::CreateAttrString(cx.llcx, "branch-target-enforcement"));
+            }
+            if let Some(PacRet { leaf, pc, key }) = pac_ret {
+                if pc {
+                    to_add.push(llvm::CreateAttrString(cx.llcx, "branch-protection-pauth-lr"));
                 }
+                to_add.push(llvm::CreateAttrStringValue(
+                    cx.llcx,
+                    "sign-return-address",
+                    if leaf { "all" } else { "non-leaf" },
+                ));
+                to_add.push(llvm::CreateAttrStringValue(
+                    cx.llcx,
+                    "sign-return-address-key",
+                    if key == PAuthKey::A { "a_key" } else { "b_key" },
+                ));
             }
         }
     }
@@ -510,12 +508,6 @@ pub(crate) fn llfn_attrs_from_instance<'ll, 'tcx>(
             InstructionSetAttr::ArmA32 => "-thumb-mode".to_string(),
             InstructionSetAttr::ArmT32 => "+thumb-mode".to_string(),
         }))
-        // HACK: LLVM versions 19+ do not have the FPMR feature and treat it as always enabled
-        // It only exists as a feature in LLVM 18, cannot be passed down for any other version
-        .chain(match &*cx.tcx.sess.target.arch {
-            "aarch64" if llvm_util::get_version().0 == 18 => vec!["+fpmr".to_string()],
-            _ => vec![],
-        })
         .collect::<Vec<String>>();
 
     if cx.tcx.sess.target.is_like_wasm {
diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index 297f104d124..35134e9f5a0 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -30,6 +30,7 @@ use smallvec::SmallVec;
 use tracing::{debug, instrument};
 
 use crate::abi::FnAbiLlvmExt;
+use crate::attributes;
 use crate::common::Funclet;
 use crate::context::{CodegenCx, FullCx, GenericCx, SCx};
 use crate::llvm::{
@@ -38,7 +39,6 @@ use crate::llvm::{
 use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
-use crate::{attributes, llvm_util};
 
 #[must_use]
 pub(crate) struct GenericBuilder<'a, 'll, CX: Borrow<SCx<'ll>>> {
@@ -927,11 +927,9 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         debug_assert_ne!(self.val_ty(val), dest_ty);
 
         let trunc = self.trunc(val, dest_ty);
-        if llvm_util::get_version() >= (19, 0, 0) {
-            unsafe {
-                if llvm::LLVMIsAInstruction(trunc).is_some() {
-                    llvm::LLVMSetNUW(trunc, True);
-                }
+        unsafe {
+            if llvm::LLVMIsAInstruction(trunc).is_some() {
+                llvm::LLVMSetNUW(trunc, True);
             }
         }
         trunc
@@ -941,11 +939,9 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         debug_assert_ne!(self.val_ty(val), dest_ty);
 
         let trunc = self.trunc(val, dest_ty);
-        if llvm_util::get_version() >= (19, 0, 0) {
-            unsafe {
-                if llvm::LLVMIsAInstruction(trunc).is_some() {
-                    llvm::LLVMSetNSW(trunc, True);
-                }
+        unsafe {
+            if llvm::LLVMIsAInstruction(trunc).is_some() {
+                llvm::LLVMSetNSW(trunc, True);
             }
         }
         trunc
@@ -1899,10 +1895,6 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
         hash: &'ll Value,
         bitmap_bits: &'ll Value,
     ) {
-        assert!(
-            crate::llvm_util::get_version() >= (19, 0, 0),
-            "MCDC intrinsics require LLVM 19 or later"
-        );
         self.call_intrinsic("llvm.instrprof.mcdc.parameters", &[fn_name, hash, bitmap_bits]);
     }
 
@@ -1914,10 +1906,6 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
         bitmap_index: &'ll Value,
         mcdc_temp: &'ll Value,
     ) {
-        assert!(
-            crate::llvm_util::get_version() >= (19, 0, 0),
-            "MCDC intrinsics require LLVM 19 or later"
-        );
         let args = &[fn_name, hash, bitmap_index, mcdc_temp];
         self.call_intrinsic("llvm.instrprof.mcdc.tvbitmap.update", args);
     }
@@ -1929,10 +1917,6 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
 
     #[instrument(level = "debug", skip(self))]
     pub(crate) fn mcdc_condbitmap_update(&mut self, cond_index: &'ll Value, mcdc_temp: &'ll Value) {
-        assert!(
-            crate::llvm_util::get_version() >= (19, 0, 0),
-            "MCDC intrinsics require LLVM 19 or later"
-        );
         let align = self.tcx.data_layout.i32_align.abi;
         let current_tv_index = self.load(self.cx.type_i32(), mcdc_temp, align);
         let new_tv_index = self.add(current_tv_index, cond_index);
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index 1e8861116e2..4ec69995518 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -164,23 +164,6 @@ pub(crate) unsafe fn create_module<'ll>(
     let mut target_data_layout = sess.target.data_layout.to_string();
     let llvm_version = llvm_util::get_version();
 
-    if llvm_version < (19, 0, 0) {
-        if sess.target.arch == "aarch64" || sess.target.arch.starts_with("arm64") {
-            // LLVM 19 sets -Fn32 in its data layout string for 64-bit ARM
-            // Earlier LLVMs leave this default, so remove it.
-            // See https://github.com/llvm/llvm-project/pull/90702
-            target_data_layout = target_data_layout.replace("-Fn32", "");
-        }
-    }
-
-    if llvm_version < (19, 0, 0) {
-        if sess.target.arch == "loongarch64" {
-            // LLVM 19 updates the LoongArch64 data layout.
-            // See https://github.com/llvm/llvm-project/pull/93814
-            target_data_layout = target_data_layout.replace("-n32:64", "-n64");
-        }
-    }
-
     if llvm_version < (20, 0, 0) {
         if sess.target.arch == "aarch64" || sess.target.arch.starts_with("arm64") {
             // LLVM 20 defines three additional address spaces for alternate
@@ -1218,10 +1201,8 @@ impl<'ll> CodegenCx<'ll, '_> {
 
         if self.sess().instrument_coverage() {
             ifn!("llvm.instrprof.increment", fn(ptr, t_i64, t_i32, t_i32) -> void);
-            if crate::llvm_util::get_version() >= (19, 0, 0) {
-                ifn!("llvm.instrprof.mcdc.parameters", fn(ptr, t_i64, t_i32) -> void);
-                ifn!("llvm.instrprof.mcdc.tvbitmap.update", fn(ptr, t_i64, t_i32, ptr) -> void);
-            }
+            ifn!("llvm.instrprof.mcdc.parameters", fn(ptr, t_i64, t_i32) -> void);
+            ifn!("llvm.instrprof.mcdc.tvbitmap.update", fn(ptr, t_i64, t_i32, ptr) -> void);
         }
 
         ifn!("llvm.type.test", fn(ptr, t_metadata) -> i1);
diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index 4e85286ed55..36e35f81392 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -256,7 +256,6 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         ("aarch64", "pmuv3") => Some(LLVMFeature::new("perfmon")),
         ("aarch64", "paca") => Some(LLVMFeature::new("pauth")),
         ("aarch64", "pacg") => Some(LLVMFeature::new("pauth")),
-        ("aarch64", "pauth-lr") if get_version().0 < 19 => None,
         // Before LLVM 20 those two features were packaged together as b16b16
         ("aarch64", "sve-b16b16") if get_version().0 < 20 => Some(LLVMFeature::new("b16b16")),
         ("aarch64", "sme-b16b16") if get_version().0 < 20 => Some(LLVMFeature::new("b16b16")),
@@ -270,20 +269,9 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         ("aarch64", "fhm") => Some(LLVMFeature::new("fp16fml")),
         ("aarch64", "fp16") => Some(LLVMFeature::new("fullfp16")),
         // Filter out features that are not supported by the current LLVM version
-        ("aarch64", "fpmr") if get_version().0 != 18 => None,
+        ("aarch64", "fpmr") => None, // only existed in 18
         ("arm", "fp16") => Some(LLVMFeature::new("fullfp16")),
-        // In LLVM 18, `unaligned-scalar-mem` was merged with `unaligned-vector-mem` into a single
-        // feature called `fast-unaligned-access`. In LLVM 19, it was split back out.
-        ("riscv32" | "riscv64", "unaligned-scalar-mem" | "unaligned-vector-mem")
-            if get_version().0 == 18 =>
-        {
-            Some(LLVMFeature::new("fast-unaligned-access"))
-        }
         // Filter out features that are not supported by the current LLVM version
-        ("riscv32" | "riscv64", "zaamo") if get_version().0 < 19 => None,
-        ("riscv32" | "riscv64", "zabha") if get_version().0 < 19 => None,
-        ("riscv32" | "riscv64", "zalrsc") if get_version().0 < 19 => None,
-        ("riscv32" | "riscv64", "zama16b") if get_version().0 < 19 => None,
         ("riscv32" | "riscv64", "zacas") if get_version().0 < 20 => None,
         // Enable the evex512 target feature if an avx512 target feature is enabled.
         ("x86", s) if s.starts_with("avx512") => {
@@ -295,10 +283,9 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         ("sparc", "leoncasa") => Some(LLVMFeature::new("hasleoncasa")),
         // In LLVM 19, there is no `v8plus` feature and `v9` means "SPARC-V9 instruction available and SPARC-V8+ ABI used".
         // https://github.com/llvm/llvm-project/blob/llvmorg-19.1.0/llvm/lib/Target/Sparc/MCTargetDesc/SparcELFObjectWriter.cpp#L27-L28
-        // Before LLVM 19, there is no `v8plus` feature and `v9` means "SPARC-V9 instruction available".
+        // Before LLVM 19, there was no `v8plus` feature and `v9` means "SPARC-V9 instruction available".
         // https://github.com/llvm/llvm-project/blob/llvmorg-18.1.0/llvm/lib/Target/Sparc/MCTargetDesc/SparcELFObjectWriter.cpp#L26
         ("sparc", "v8plus") if get_version().0 == 19 => Some(LLVMFeature::new("v9")),
-        ("sparc", "v8plus") if get_version().0 < 19 => None,
         ("powerpc", "power8-crypto") => Some(LLVMFeature::new("crypto")),
         // These new `amx` variants and `movrs` were introduced in LLVM20
         ("x86", "amx-avx512" | "amx-fp8" | "amx-movrs" | "amx-tf32" | "amx-transpose")
diff --git a/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
index b8884486c33..4695de8ea09 100644
--- a/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
@@ -47,7 +47,6 @@ struct LLVMRustMCDCBranchParameters {
   int16_t ConditionIDs[2];
 };
 
-#if LLVM_VERSION_GE(19, 0)
 static coverage::mcdc::BranchParameters
 fromRust(LLVMRustMCDCBranchParameters Params) {
   return coverage::mcdc::BranchParameters(
@@ -59,7 +58,6 @@ fromRust(LLVMRustMCDCDecisionParameters Params) {
   return coverage::mcdc::DecisionParameters(Params.BitmapIdx,
                                             Params.NumConditions);
 }
-#endif
 
 // Must match the layout of
 // `rustc_codegen_llvm::coverageinfo::ffi::CoverageSpan`.
@@ -203,7 +201,6 @@ extern "C" void LLVMRustCoverageWriteFunctionMappingsToBuffer(
         Region.Span.LineEnd, Region.Span.ColumnEnd));
   }
 
-#if LLVM_VERSION_GE(19, 0)
   // MC/DC branch regions:
   for (const auto &Region : ArrayRef(MCDCBranchRegions, NumMCDCBranchRegions)) {
     MappingRegions.push_back(coverage::CounterMappingRegion::makeBranchRegion(
@@ -221,7 +218,6 @@ extern "C" void LLVMRustCoverageWriteFunctionMappingsToBuffer(
         Region.Span.LineStart, Region.Span.ColumnStart, Region.Span.LineEnd,
         Region.Span.ColumnEnd));
   }
-#endif
 
   // Write the converted expressions and mappings to a byte buffer.
   auto CoverageMappingWriter = coverage::CoverageMappingWriter(
diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
index 257bdc01993..e02c80c50b1 100644
--- a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
@@ -47,10 +47,7 @@
 #include <vector>
 
 // Conditional includes prevent clang-format from fully sorting the list,
-// so keep them separate.
-#if LLVM_VERSION_GE(19, 0)
-#include "llvm/Support/PGOOptions.h"
-#endif
+// so if any are needed, keep them separate down here.
 
 using namespace llvm;
 
@@ -432,31 +429,15 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
   }
   if (!strcmp("zlib", DebugInfoCompression) &&
       llvm::compression::zlib::isAvailable()) {
-#if LLVM_VERSION_GE(19, 0)
     Options.MCOptions.CompressDebugSections = DebugCompressionType::Zlib;
-#else
-    Options.CompressDebugSections = DebugCompressionType::Zlib;
-#endif
   } else if (!strcmp("zstd", DebugInfoCompression) &&
              llvm::compression::zstd::isAvailable()) {
-#if LLVM_VERSION_GE(19, 0)
     Options.MCOptions.CompressDebugSections = DebugCompressionType::Zstd;
-#else
-    Options.CompressDebugSections = DebugCompressionType::Zstd;
-#endif
   } else if (!strcmp("none", DebugInfoCompression)) {
-#if LLVM_VERSION_GE(19, 0)
     Options.MCOptions.CompressDebugSections = DebugCompressionType::None;
-#else
-    Options.CompressDebugSections = DebugCompressionType::None;
-#endif
   }
 
-#if LLVM_VERSION_GE(19, 0)
   Options.MCOptions.X86RelaxRelocations = RelaxELFRelocations;
-#else
-  Options.RelaxELFRelocations = RelaxELFRelocations;
-#endif
   Options.UseInitArray = UseInitArray;
   Options.EmulatedTLS = UseEmulatedTls;
 
@@ -753,34 +734,23 @@ extern "C" LLVMRustResult LLVMRustOptimize(
   auto FS = vfs::getRealFileSystem();
   if (PGOGenPath) {
     assert(!PGOUsePath && !PGOSampleUsePath);
-    PGOOpt = PGOOptions(PGOGenPath, "", "", "", FS, PGOOptions::IRInstr,
-                        PGOOptions::NoCSAction,
-#if LLVM_VERSION_GE(19, 0)
-                        PGOOptions::ColdFuncOpt::Default,
-#endif
-                        DebugInfoForProfiling);
+    PGOOpt = PGOOptions(
+        PGOGenPath, "", "", "", FS, PGOOptions::IRInstr, PGOOptions::NoCSAction,
+        PGOOptions::ColdFuncOpt::Default, DebugInfoForProfiling);
   } else if (PGOUsePath) {
     assert(!PGOSampleUsePath);
-    PGOOpt = PGOOptions(PGOUsePath, "", "", "", FS, PGOOptions::IRUse,
-                        PGOOptions::NoCSAction,
-#if LLVM_VERSION_GE(19, 0)
-                        PGOOptions::ColdFuncOpt::Default,
-#endif
-                        DebugInfoForProfiling);
+    PGOOpt = PGOOptions(
+        PGOUsePath, "", "", "", FS, PGOOptions::IRUse, PGOOptions::NoCSAction,
+        PGOOptions::ColdFuncOpt::Default, DebugInfoForProfiling);
   } else if (PGOSampleUsePath) {
-    PGOOpt = PGOOptions(PGOSampleUsePath, "", "", "", FS, PGOOptions::SampleUse,
-                        PGOOptions::NoCSAction,
-#if LLVM_VERSION_GE(19, 0)
-                        PGOOptions::ColdFuncOpt::Default,
-#endif
-                        DebugInfoForProfiling);
+    PGOOpt =
+        PGOOptions(PGOSampleUsePath, "", "", "", FS, PGOOptions::SampleUse,
+                   PGOOptions::NoCSAction, PGOOptions::ColdFuncOpt::Default,
+                   DebugInfoForProfiling);
   } else if (DebugInfoForProfiling) {
-    PGOOpt = PGOOptions("", "", "", "", FS, PGOOptions::NoAction,
-                        PGOOptions::NoCSAction,
-#if LLVM_VERSION_GE(19, 0)
-                        PGOOptions::ColdFuncOpt::Default,
-#endif
-                        DebugInfoForProfiling);
+    PGOOpt = PGOOptions(
+        "", "", "", "", FS, PGOOptions::NoAction, PGOOptions::NoCSAction,
+        PGOOptions::ColdFuncOpt::Default, DebugInfoForProfiling);
   }
 
   auto PB = PassBuilder(TM, PTO, PGOOpt, &PIC);
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index 32e6da446d7..5f0e4d745e8 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -473,12 +473,8 @@ extern "C" LLVMAttributeRef
 LLVMRustCreateRangeAttribute(LLVMContextRef C, unsigned NumBits,
                              const uint64_t LowerWords[],
                              const uint64_t UpperWords[]) {
-#if LLVM_VERSION_GE(19, 0)
   return LLVMCreateConstantRangeAttribute(C, Attribute::Range, NumBits,
                                           LowerWords, UpperWords);
-#else
-  report_fatal_error("LLVM 19.0 is required for Range Attribute");
-#endif
 }
 
 // These values **must** match ffi::AllocKindFlags.
@@ -1601,43 +1597,6 @@ extern "C" LLVMValueRef LLVMRustBuildMemSet(LLVMBuilderRef B, LLVMValueRef Dst,
                                       MaybeAlign(DstAlign), IsVolatile));
 }
 
-// Polyfill for `LLVMBuildCallBr`, which was added in LLVM 19.
-// <https://github.com/llvm/llvm-project/commit/584253c4e2f788f870488fc32193b52d67ddaccc>
-// FIXME: Remove when Rust's minimum supported LLVM version reaches 19.
-#if LLVM_VERSION_LT(19, 0)
-DEFINE_SIMPLE_CONVERSION_FUNCTIONS(OperandBundleDef, LLVMOperandBundleRef)
-
-extern "C" LLVMValueRef
-LLVMBuildCallBr(LLVMBuilderRef B, LLVMTypeRef Ty, LLVMValueRef Fn,
-                LLVMBasicBlockRef DefaultDest, LLVMBasicBlockRef *IndirectDests,
-                unsigned NumIndirectDests, LLVMValueRef *Args, unsigned NumArgs,
-                LLVMOperandBundleRef *Bundles, unsigned NumBundles,
-                const char *Name) {
-  Value *Callee = unwrap(Fn);
-  FunctionType *FTy = unwrap<FunctionType>(Ty);
-
-  // FIXME: Is there a way around this?
-  std::vector<BasicBlock *> IndirectDestsUnwrapped;
-  IndirectDestsUnwrapped.reserve(NumIndirectDests);
-  for (unsigned i = 0; i < NumIndirectDests; ++i) {
-    IndirectDestsUnwrapped.push_back(unwrap(IndirectDests[i]));
-  }
-
-  // FIXME: Is there a way around this?
-  SmallVector<OperandBundleDef> OpBundles;
-  OpBundles.reserve(NumBundles);
-  for (unsigned i = 0; i < NumBundles; ++i) {
-    OpBundles.push_back(*unwrap(Bundles[i]));
-  }
-
-  return wrap(
-      unwrap(B)->CreateCallBr(FTy, Callee, unwrap(DefaultDest),
-                              ArrayRef<BasicBlock *>(IndirectDestsUnwrapped),
-                              ArrayRef<Value *>(unwrap(Args), NumArgs),
-                              ArrayRef<OperandBundleDef>(OpBundles), Name));
-}
-#endif
-
 extern "C" void LLVMRustPositionBuilderAtStart(LLVMBuilderRef B,
                                                LLVMBasicBlockRef BB) {
   auto Point = unwrap(BB)->getFirstInsertionPt();
@@ -1781,24 +1740,6 @@ extern "C" LLVMValueRef LLVMRustBuildMaxNum(LLVMBuilderRef B, LLVMValueRef LHS,
   return wrap(unwrap(B)->CreateMaxNum(unwrap(LHS), unwrap(RHS)));
 }
 
-#if LLVM_VERSION_LT(19, 0)
-enum {
-  LLVMGEPFlagInBounds = (1 << 0),
-  LLVMGEPFlagNUSW = (1 << 1),
-  LLVMGEPFlagNUW = (1 << 2),
-};
-extern "C" LLVMValueRef
-LLVMBuildGEPWithNoWrapFlags(LLVMBuilderRef B, LLVMTypeRef Ty,
-                            LLVMValueRef Pointer, LLVMValueRef *Indices,
-                            unsigned NumIndices, const char *Name,
-                            unsigned NoWrapFlags) {
-  if (NoWrapFlags & LLVMGEPFlagInBounds)
-    return LLVMBuildInBoundsGEP2(B, Ty, Pointer, Indices, NumIndices, Name);
-  else
-    return LLVMBuildGEP2(B, Ty, Pointer, Indices, NumIndices, Name);
-}
-#endif
-
 // Transfers ownership of DiagnosticHandler unique_ptr to the caller.
 extern "C" DiagnosticHandler *
 LLVMRustContextGetDiagnosticHandler(LLVMContextRef C) {
@@ -1866,11 +1807,7 @@ extern "C" void LLVMRustContextConfigureDiagnosticHandler(
         }
       }
       if (DiagnosticHandlerCallback) {
-#if LLVM_VERSION_GE(19, 0)
         DiagnosticHandlerCallback(&DI, DiagnosticHandlerContext);
-#else
-        DiagnosticHandlerCallback(DI, DiagnosticHandlerContext);
-#endif
         return true;
       }
       return false;
@@ -2018,21 +1955,3 @@ extern "C" void LLVMRustSetNoSanitizeHWAddress(LLVMValueRef Global) {
   MD.NoHWAddress = true;
   GV.setSanitizerMetadata(MD);
 }
-
-// Operations on composite constants.
-// These are clones of LLVM api functions that will become available in future
-// releases. They can be removed once Rust's minimum supported LLVM version
-// supports them. See https://github.com/rust-lang/rust/issues/121868 See
-// https://llvm.org/doxygen/group__LLVMCCoreValueConstantComposite.html
-
-// FIXME: Remove when Rust's minimum supported LLVM version reaches 19.
-// https://github.com/llvm/llvm-project/commit/e1405e4f71c899420ebf8262d5e9745598419df8
-#if LLVM_VERSION_LT(19, 0)
-extern "C" LLVMValueRef LLVMConstStringInContext2(LLVMContextRef C,
-                                                  const char *Str,
-                                                  size_t Length,
-                                                  bool DontNullTerminate) {
-  return wrap(ConstantDataArray::getString(*unwrap(C), StringRef(Str, Length),
-                                           !DontNullTerminate));
-}
-#endif