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| author | bors <bors@rust-lang.org> | 2024-02-21 09:43:33 +0000 |
|---|---|---|
| committer | bors <bors@rust-lang.org> | 2024-02-21 09:43:33 +0000 |
| commit | 709c00a04728dc98b09f63ccb3cb526de80e122f (patch) | |
| tree | 5abfd650be0276ca9b38c4397dad982f95734f63 | |
| parent | 4f23c244e959c8d3f05069939c0f23ec9f30599d (diff) | |
| parent | 968e79540da9d3a29cf8e57390b4775fd0bd0616 (diff) | |
| download | rust-709c00a04728dc98b09f63ccb3cb526de80e122f.tar.gz rust-709c00a04728dc98b09f63ccb3cb526de80e122f.zip | |
Auto merge of #120718 - saethlin:reasonable-fast-math, r=nnethercote
Add "algebraic" fast-math intrinsics, based on fast-math ops that cannot return poison Setting all of LLVM's fast-math flags makes our fast-math intrinsics very dangerous, because some inputs are UB. This set of flags permits common algebraic transformations, but according to the [LangRef](https://llvm.org/docs/LangRef.html#fastmath), only the flags `nnan` (no nans) and `ninf` (no infs) can produce poison. And this uses the algebraic float ops to fix https://github.com/rust-lang/rust/issues/120720 cc `@orlp`
| -rw-r--r-- | src/intrinsics/mod.rs | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/src/intrinsics/mod.rs b/src/intrinsics/mod.rs index 476752c7230..199d5df29e7 100644 --- a/src/intrinsics/mod.rs +++ b/src/intrinsics/mod.rs @@ -1152,17 +1152,26 @@ fn codegen_regular_intrinsic_call<'tcx>( ret.write_cvalue(fx, ret_val); } - sym::fadd_fast | sym::fsub_fast | sym::fmul_fast | sym::fdiv_fast | sym::frem_fast => { + sym::fadd_fast + | sym::fsub_fast + | sym::fmul_fast + | sym::fdiv_fast + | sym::frem_fast + | sym::fadd_algebraic + | sym::fsub_algebraic + | sym::fmul_algebraic + | sym::fdiv_algebraic + | sym::frem_algebraic => { intrinsic_args!(fx, args => (x, y); intrinsic); let res = crate::num::codegen_float_binop( fx, match intrinsic { - sym::fadd_fast => BinOp::Add, - sym::fsub_fast => BinOp::Sub, - sym::fmul_fast => BinOp::Mul, - sym::fdiv_fast => BinOp::Div, - sym::frem_fast => BinOp::Rem, + sym::fadd_fast | sym::fadd_algebraic => BinOp::Add, + sym::fsub_fast | sym::fsub_algebraic => BinOp::Sub, + sym::fmul_fast | sym::fmul_algebraic => BinOp::Mul, + sym::fdiv_fast | sym::fdiv_algebraic => BinOp::Div, + sym::frem_fast | sym::frem_algebraic => BinOp::Rem, _ => unreachable!(), }, x, |