Auto merge of #124111 - matthiaskrgr:rollup-cmmkryf, r=matthiaskrgr

Rollup of 5 pull requests

Successful merges:

 - #124041 (Fix copy path button)
 - #124047 (Match ergonomics 2024: miscellaneous code cleanups)
 - #124064 (Move confusing comment about otherwise blocks in `lower_match_tree`)
 - #124090 (llvm: update riscv target feature to match LLVM 19)
 - #124100 (fix: make `str::from_raw_parts_mut` `mut`)

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 4 insertions, 3 deletions

diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index c9e62e504ae..5552b381025 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -270,9 +270,10 @@ pub fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> LLVMFeature<'a> {
             "sve2-bitperm",
             TargetFeatureFoldStrength::EnableOnly("neon"),
         ),
-        // The unaligned-scalar-mem feature was renamed to fast-unaligned-access.
-        ("riscv32" | "riscv64", "fast-unaligned-access") if get_version().0 <= 17 => {
-            LLVMFeature::new("unaligned-scalar-mem")
+        // 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 => {
+            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") => {