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Auto merge of #137271 - nikic:gep-nuw-2, r=scottmcm

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Emit getelementptr inbounds nuw for pointer::add()

Lower pointer::add (via intrinsic::offset with unsigned offset) to getelementptr inbounds nuw on LLVM versions that support it. This lets LLVM make use of the pre-condition that the offset addition does not wrap in an unsigned sense. Together with inbounds, this also implies that the offset is non-negative.

Fixes https://github.com/rust-lang/rust/issues/137217.
This commit is contained in:
bors 2025-02-24 03:06:16 +00:00
commit e0be1a0262
10 changed files with 93 additions and 29 deletions
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22
compiler/rustc_codegen_llvm/src/llvm/ffi.rs
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@ -954,6 +954,17 @@ bitflags! {
}
}
// These values **must** match with LLVMGEPNoWrapFlags
bitflags! {
#[repr(transparent)]
#[derive(Default)]
pub struct GEPNoWrapFlags : c_uint {
const InBounds = 1 << 0;
const NUSW = 1 << 1;
const NUW = 1 << 2;
}
}
unsafe extern "C" {
pub type ModuleBuffer;
}
@ -1454,21 +1465,14 @@ unsafe extern "C" {
pub(crate) fn LLVMBuildStore<'a>(B: &Builder<'a>, Val: &'a Value, Ptr: &'a Value) -> &'a Value;
pub(crate) fn LLVMBuildGEP2<'a>(
B: &Builder<'a>,
Ty: &'a Type,
Pointer: &'a Value,
Indices: *const &'a Value,
NumIndices: c_uint,
Name: *const c_char,
) -> &'a Value;
pub(crate) fn LLVMBuildInBoundsGEP2<'a>(
pub(crate) fn LLVMBuildGEPWithNoWrapFlags<'a>(
B: &Builder<'a>,
Ty: &'a Type,
Pointer: &'a Value,
Indices: *const &'a Value,
NumIndices: c_uint,
Name: *const c_char,
Flags: GEPNoWrapFlags,
) -> &'a Value;
// Casts