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Auto merge of #133984 - DaniPopes:scmp-ucmp, r=scottmcm

Lower BinOp::Cmp to llvm.{s,u}cmp.* intrinsics

Lowers `mir::BinOp::Cmp` (`three_way_compare` intrinsic) to the corresponding LLVM `llvm.{s,u}cmp.i8.*` intrinsics.

These are the intrinsics mentioned in https://github.com/rust-lang/rust/pull/118310, which are now available in LLVM 19.

I couldn't find any follow-up PRs/discussions about this, please let me know if I missed something.

r? `@scottmcm`
This commit is contained in:
bors 2025-03-24 22:53:12 +00:00
commit 1df5affaca
8 changed files with 124 additions and 42 deletions

View file

@ -1127,6 +1127,18 @@ impl<'ll> CodegenCx<'ll, '_> {
ifn!("llvm.usub.sat.i64", fn(t_i64, t_i64) -> t_i64);
ifn!("llvm.usub.sat.i128", fn(t_i128, t_i128) -> t_i128);
ifn!("llvm.scmp.i8.i8", fn(t_i8, t_i8) -> t_i8);
ifn!("llvm.scmp.i8.i16", fn(t_i16, t_i16) -> t_i8);
ifn!("llvm.scmp.i8.i32", fn(t_i32, t_i32) -> t_i8);
ifn!("llvm.scmp.i8.i64", fn(t_i64, t_i64) -> t_i8);
ifn!("llvm.scmp.i8.i128", fn(t_i128, t_i128) -> t_i8);
ifn!("llvm.ucmp.i8.i8", fn(t_i8, t_i8) -> t_i8);
ifn!("llvm.ucmp.i8.i16", fn(t_i16, t_i16) -> t_i8);
ifn!("llvm.ucmp.i8.i32", fn(t_i32, t_i32) -> t_i8);
ifn!("llvm.ucmp.i8.i64", fn(t_i64, t_i64) -> t_i8);
ifn!("llvm.ucmp.i8.i128", fn(t_i128, t_i128) -> t_i8);
ifn!("llvm.lifetime.start.p0i8", fn(t_i64, ptr) -> void);
ifn!("llvm.lifetime.end.p0i8", fn(t_i64, ptr) -> void);