Update the minimum external LLVM to 18

4 files changed, 7 insertions, 48 deletions

diff --git a/compiler/rustc_codegen_llvm/src/abi.rs b/compiler/rustc_codegen_llvm/src/abi.rs
index e318e615d1f..26718792f5f 100644
--- a/compiler/rustc_codegen_llvm/src/abi.rs
+++ b/compiler/rustc_codegen_llvm/src/abi.rs
@@ -465,9 +465,7 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
                     cx.type_array(cx.type_i8(), self.ret.layout.size.bytes()),
                 );
                 attributes::apply_to_llfn(llfn, llvm::AttributePlace::Argument(i), &[sret]);
-                if cx.sess().opts.optimize != config::OptLevel::No
-                    && llvm_util::get_version() >= (18, 0, 0)
-                {
+                if cx.sess().opts.optimize != config::OptLevel::No {
                     attributes::apply_to_llfn(
                         llfn,
                         llvm::AttributePlace::Argument(i),
diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index 577d0869866..c806d0c5499 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -26,13 +26,13 @@ use smallvec::SmallVec;
 use tracing::{debug, instrument};
 
 use crate::abi::FnAbiLlvmExt;
+use crate::attributes;
 use crate::common::Funclet;
 use crate::context::CodegenCx;
 use crate::llvm::{self, AtomicOrdering, AtomicRmwBinOp, BasicBlock, False, True};
 use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
-use crate::{attributes, llvm_util};
 
 // All Builders must have an llfn associated with them
 #[must_use]
@@ -1311,15 +1311,9 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     }
 
     fn apply_attrs_to_cleanup_callsite(&mut self, llret: &'ll Value) {
-        if llvm_util::get_version() < (17, 0, 2) {
-            // Work around https://github.com/llvm/llvm-project/issues/66984.
-            let noinline = llvm::AttributeKind::NoInline.create_attr(self.llcx);
-            attributes::apply_to_callsite(llret, llvm::AttributePlace::Function, &[noinline]);
-        } else {
-            // Cleanup is always the cold path.
-            let cold_inline = llvm::AttributeKind::Cold.create_attr(self.llcx);
-            attributes::apply_to_callsite(llret, llvm::AttributePlace::Function, &[cold_inline]);
-        }
+        // Cleanup is always the cold path.
+        let cold_inline = llvm::AttributeKind::Cold.create_attr(self.llcx);
+        attributes::apply_to_callsite(llret, llvm::AttributePlace::Function, &[cold_inline]);
     }
 }
 
@@ -1761,8 +1755,6 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
     ) {
         debug!("mcdc_parameters() with args ({:?}, {:?}, {:?})", fn_name, hash, bitmap_bytes);
 
-        assert!(llvm_util::get_version() >= (18, 0, 0), "MCDC intrinsics require LLVM 18 or later");
-
         let llfn = unsafe { llvm::LLVMRustGetInstrProfMCDCParametersIntrinsic(self.cx().llmod) };
         let llty = self.cx.type_func(
             &[self.cx.type_ptr(), self.cx.type_i64(), self.cx.type_i32()],
@@ -1796,7 +1788,6 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
             "mcdc_tvbitmap_update() with args ({:?}, {:?}, {:?}, {:?}, {:?})",
             fn_name, hash, bitmap_bytes, bitmap_index, mcdc_temp
         );
-        assert!(llvm_util::get_version() >= (18, 0, 0), "MCDC intrinsics require LLVM 18 or later");
 
         let llfn =
             unsafe { llvm::LLVMRustGetInstrProfMCDCTVBitmapUpdateIntrinsic(self.cx().llmod) };
@@ -1838,7 +1829,6 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
             "mcdc_condbitmap_update() with args ({:?}, {:?}, {:?}, {:?}, {:?})",
             fn_name, hash, cond_loc, mcdc_temp, bool_value
         );
-        assert!(llvm_util::get_version() >= (18, 0, 0), "MCDC intrinsics require LLVM 18 or later");
         let llfn = unsafe { llvm::LLVMRustGetInstrProfMCDCCondBitmapIntrinsic(self.cx().llmod) };
         let llty = self.cx.type_func(
             &[
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index dd9c184fdc4..03af31d36fb 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -120,14 +120,6 @@ 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 < (18, 0, 0) {
-        if sess.target.arch == "x86" || sess.target.arch == "x86_64" {
-            // LLVM 18 adjusts i128 to be 128-bit aligned on x86 variants.
-            // Earlier LLVMs leave this as default alignment, so remove it.
-            // See https://reviews.llvm.org/D86310
-            target_data_layout = target_data_layout.replace("-i128:128", "");
-        }
-    }
 
     if llvm_version < (19, 0, 0) {
         if sess.target.arch == "aarch64" || sess.target.arch.starts_with("arm64") {
diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index 29afe6f6bfc..358bfcb1573 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -258,28 +258,14 @@ 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", "faminmax") if get_version().0 < 18 => None,
-        ("aarch64", "fp8") if get_version().0 < 18 => None,
-        ("aarch64", "fp8dot2") if get_version().0 < 18 => None,
-        ("aarch64", "fp8dot4") if get_version().0 < 18 => None,
-        ("aarch64", "fp8fma") if get_version().0 < 18 => None,
         ("aarch64", "fpmr") if get_version().0 != 18 => None,
-        ("aarch64", "lut") if get_version().0 < 18 => None,
-        ("aarch64", "sme-f8f16") if get_version().0 < 18 => None,
-        ("aarch64", "sme-f8f32") if get_version().0 < 18 => None,
-        ("aarch64", "sme-fa64") if get_version().0 < 18 => None,
-        ("aarch64", "sme-lutv2") if get_version().0 < 18 => None,
-        ("aarch64", "ssve-fp8dot2") if get_version().0 < 18 => None,
-        ("aarch64", "ssve-fp8dot4") if get_version().0 < 18 => None,
-        ("aarch64", "ssve-fp8fma") if get_version().0 < 18 => None,
-        ("aarch64", "v9.5a") if get_version().0 < 18 => None,
         // 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") if get_version().0 == 18 => {
             Some(LLVMFeature::new("fast-unaligned-access"))
         }
-        // For LLVM 18, enable the evex512 target feature if a avx512 target feature is enabled.
-        ("x86", s) if get_version().0 >= 18 && s.starts_with("avx512") => {
+        // Enable the evex512 target feature if an avx512 target feature is enabled.
+        ("x86", s) if s.starts_with("avx512") => {
             Some(LLVMFeature::with_dependency(s, TargetFeatureFoldStrength::EnableOnly("evex512")))
         }
         (_, s) => Some(LLVMFeature::new(s)),
@@ -587,7 +573,6 @@ pub(crate) fn global_llvm_features(
     // -Ctarget-features
     if !only_base_features {
         let supported_features = sess.target.supported_target_features();
-        let (llvm_major, _, _) = get_version();
         let mut featsmap = FxHashMap::default();
 
         // insert implied features
@@ -664,12 +649,6 @@ pub(crate) fn global_llvm_features(
                     return None;
                 }
 
-                // if the target-feature is "backchain" and LLVM version is greater than 18
-                // then we also need to add "+backchain" to the target-features attribute.
-                // otherwise, we will only add the naked `backchain` attribute to the attribute-group.
-                if feature == "backchain" && llvm_major < 18 {
-                    return None;
-                }
                 // ... otherwise though we run through `to_llvm_features` when
                 // passing requests down to LLVM. This means that all in-language
                 // features also work on the command line instead of having two