bjoernager/rust
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Auto merge of #136575 - scottmcm:nsuw-math, r=nikic

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Set both `nuw` and `nsw` in slice size calculation

There's an old note in the code to do this, and now that [LLVM-C has an API for it](f0b8ff1251/llvm/include/llvm-c/Core.h (L4403-L4408)), we might as well.  And it's been there since what looks like LLVM 17 de9b6aa341 so doesn't even need to be conditional.

(There's other places, like `RawVecInner` or `Layout`, that might want to do things like this too, but I'll leave those for a future PR.)
This commit is contained in:
bors 2025-02-14 14:21:29 +00:00
commit bdc97d1046
7 changed files with 81 additions and 44 deletions
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31
compiler/rustc_codegen_llvm/src/builder.rs
View file

@ -421,6 +421,37 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
unchecked_umul(x, y) => LLVMBuildNUWMul,
}
fn unchecked_suadd(&mut self, a: &'ll Value, b: &'ll Value) -> &'ll Value {
unsafe {
let add = llvm::LLVMBuildAdd(self.llbuilder, a, b, UNNAMED);
if llvm::LLVMIsAInstruction(add).is_some() {
llvm::LLVMSetNUW(add, True);
llvm::LLVMSetNSW(add, True);
}
add
}
}
fn unchecked_susub(&mut self, a: &'ll Value, b: &'ll Value) -> &'ll Value {
unsafe {
let sub = llvm::LLVMBuildSub(self.llbuilder, a, b, UNNAMED);
if llvm::LLVMIsAInstruction(sub).is_some() {
llvm::LLVMSetNUW(sub, True);
llvm::LLVMSetNSW(sub, True);
}
sub
}
}
fn unchecked_sumul(&mut self, a: &'ll Value, b: &'ll Value) -> &'ll Value {
unsafe {
let mul = llvm::LLVMBuildMul(self.llbuilder, a, b, UNNAMED);
if llvm::LLVMIsAInstruction(mul).is_some() {
llvm::LLVMSetNUW(mul, True);
llvm::LLVMSetNSW(mul, True);
}
mul
}
}
fn or_disjoint(&mut self, a: &'ll Value, b: &'ll Value) -> &'ll Value {
unsafe {
let or = llvm::LLVMBuildOr(self.llbuilder, a, b, UNNAMED);

2
compiler/rustc_codegen_llvm/src/llvm/ffi.rs
View file

@ -1430,6 +1430,8 @@ unsafe extern "C" {
// Extra flags on arithmetic
pub(crate) fn LLVMSetIsDisjoint(Instr: &Value, IsDisjoint: Bool);
pub(crate) fn LLVMSetNUW(ArithInst: &Value, HasNUW: Bool);
pub(crate) fn LLVMSetNSW(ArithInst: &Value, HasNSW: Bool);
// Memory
pub(crate) fn LLVMBuildAlloca<'a>(