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Auto merge of #122220 - saethlin:ppc-can-into-atomicptr, r=oli-obk 

Only generate a ptrtoint in AtomicPtr codegen when absolutely necessary

This special case was added in this PR: https://github.com/rust-lang/rust/pull/77611 in response to this error message:
```
Intrinsic has incorrect argument type!
void ({}*)* `@llvm.ppc.cfence.p0sl_s`
in function rust_oom
LLVM ERROR: Broken function found, compilation aborted!
[RUSTC-TIMING] std test:false 20.161
error: could not compile `std`
```
But when I tried searching for more information about that intrinsic I found this: https://github.com/llvm/llvm-project/issues/55983 which is a report of someone hitting this same error and a fix was landed in LLVM, 2 years after the above Rust PR.
This commit is contained in:
bors 2024-03-13 00:03:50 +00:00
parent a165f1f650 aa6cfb2669
commit e61dcc7a0a
3 changed files with 18 additions and 42 deletions
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8
compiler/rustc_codegen_llvm/src/builder.rs
View File

@ -1132,9 +1132,15 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
&mut self,
op: rustc_codegen_ssa::common::AtomicRmwBinOp,
dst: &'ll Value,
src: &'ll Value,
mut src: &'ll Value,
order: rustc_codegen_ssa::common::AtomicOrdering,
) -> &'ll Value {
// The only RMW operation that LLVM supports on pointers is compare-exchange.
if self.val_ty(src) == self.type_ptr()
&& op != rustc_codegen_ssa::common::AtomicRmwBinOp::AtomicXchg
{
src = self.ptrtoint(src, self.type_isize());
}
unsafe {
llvm::LLVMBuildAtomicRMW(
self.llbuilder,

2
compiler/rustc_codegen_ssa/src/common.rs
View File

@ -42,7 +42,7 @@ pub enum RealPredicate {
RealPredicateTrue,
}
#[derive(Copy, Clone)]
#[derive(Copy, Clone, PartialEq)]
pub enum AtomicRmwBinOp {
AtomicXchg,
AtomicAdd,

50
compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
View File

@ -350,14 +350,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_unsafe_ptr() {
let weak = instruction == "cxchgweak";
let dst = args[0].immediate();
let mut cmp = args[1].immediate();
let mut src = args[2].immediate();
if ty.is_unsafe_ptr() {
// Some platforms do not support atomic operations on pointers,
// so we cast to integer first.
cmp = bx.ptrtoint(cmp, bx.type_isize());
src = bx.ptrtoint(src, bx.type_isize());
}
let cmp = args[1].immediate();
let src = args[2].immediate();
let (val, success) = bx.atomic_cmpxchg(
dst,
cmp,
@ -385,26 +379,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
let layout = bx.layout_of(ty);
let size = layout.size;
let source = args[0].immediate();
if ty.is_unsafe_ptr() {
// Some platforms do not support atomic operations on pointers,
// so we cast to integer first...
let llty = bx.type_isize();
let result = bx.atomic_load(
llty,
source,
parse_ordering(bx, ordering),
size,
);
// ... and then cast the result back to a pointer
bx.inttoptr(result, bx.backend_type(layout))
} else {
bx.atomic_load(
bx.backend_type(layout),
source,
parse_ordering(bx, ordering),
size,
)
}
bx.atomic_load(
bx.backend_type(layout),
source,
parse_ordering(bx, ordering),
size,
)
} else {
invalid_monomorphization(ty);
return Ok(());
@ -415,13 +395,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
let ty = fn_args.type_at(0);
if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_unsafe_ptr() {
let size = bx.layout_of(ty).size;
let mut val = args[1].immediate();
let val = args[1].immediate();
let ptr = args[0].immediate();
if ty.is_unsafe_ptr() {
// Some platforms do not support atomic operations on pointers,
// so we cast to integer first.
val = bx.ptrtoint(val, bx.type_isize());
}
bx.atomic_store(val, ptr, parse_ordering(bx, ordering), size);
} else {
invalid_monomorphization(ty);
@ -465,12 +440,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
let ty = fn_args.type_at(0);
if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_unsafe_ptr() {
let ptr = args[0].immediate();
let mut val = args[1].immediate();
if ty.is_unsafe_ptr() {
// Some platforms do not support atomic operations on pointers,
// so we cast to integer first.
val = bx.ptrtoint(val, bx.type_isize());
}
let val = args[1].immediate();
bx.atomic_rmw(atom_op, ptr, val, parse_ordering(bx, ordering))
} else {
invalid_monomorphization(ty);