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5dcb678ad8
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` |
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