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| author | bors <bors@rust-lang.org> | 2024-04-15 08:07:47 +0000 |
|---|---|---|
| committer | bors <bors@rust-lang.org> | 2024-04-15 08:07:47 +0000 |
| commit | 5dcb678ad8dc23a518f9ddf907e6a08de923d05e (patch) | |
| tree | 12c92f45e44d73f498a0e816ec037832285a49a7 /library/std/src | |
| parent | 85b884b0582d91e4b2e8ba9968ce50a3f549e8af (diff) | |
| parent | 6b794f6c802600fc9ae0c68fcaed1143fc85ab0a (diff) | |
| download | rust-5dcb678ad8dc23a518f9ddf907e6a08de923d05e.tar.gz rust-5dcb678ad8dc23a518f9ddf907e6a08de923d05e.zip | |
Auto merge of #122917 - saethlin:atomicptr-to-int, r=nikic
Add the missing inttoptr when we ptrtoint in ptr atomics
Ralf noticed this here: https://github.com/rust-lang/rust/pull/122220#discussion_r1535172094
Our previous codegen forgot to add the cast back to integer type. The code compiles anyway, because of course all locals are in-memory to start with, so previous codegen would do the integer atomic, store the integer to a local, then load a pointer from that local. Which is definitely _not_ what we wanted: That's an integer-to-pointer transmute, so all pointers returned by these `AtomicPtr` methods didn't have provenance. Yikes.
Here's the IR for `AtomicPtr::fetch_byte_add` on 1.76: https://godbolt.org/z/8qTEjeraY
```llvm
define noundef ptr `@atomicptr_fetch_byte_add(ptr` noundef nonnull align 8 %a, i64 noundef %v) unnamed_addr #0 !dbg !7 {
start:
%0 = alloca ptr, align 8, !dbg !12
%val = inttoptr i64 %v to ptr, !dbg !12
call void `@llvm.lifetime.start.p0(i64` 8, ptr %0), !dbg !28
%1 = ptrtoint ptr %val to i64, !dbg !28
%2 = atomicrmw add ptr %a, i64 %1 monotonic, align 8, !dbg !28
store i64 %2, ptr %0, align 8, !dbg !28
%self = load ptr, ptr %0, align 8, !dbg !28
call void `@llvm.lifetime.end.p0(i64` 8, ptr %0), !dbg !28
ret ptr %self, !dbg !33
}
```
r? `@RalfJung`
cc `@nikic`
Diffstat (limited to 'library/std/src')
0 files changed, 0 insertions, 0 deletions