| Issue |
120932
|
| Summary |
[FuncAttrs] volatile memcpy should not be eliminated
|
| Labels |
miscompilation,
llvm::Attributor
|
| Assignees |
|
| Reporter |
dtcxzyw
|
Reproducer: https://godbolt.org/z/n4j66We8h
```
; bin/opt -O3 test.ll -S
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
%struct.S0 = type { i32, i32, i64, i16 }
@g_148 = constant %struct.S0 { i32 568401685, i32 -1, i64 -1, i16 -1 }
define i32 @main() {
entry:
%call2 = call i32 @func_127()
ret i32 0
}
define i32 @func_127() {
entry:
%call241 = call ptr @func_144(ptr null)
%call58 = call i32 @func_139(ptr %call241)
ret i32 0
}
define internal i32 @func_139(ptr %p_140) {
entry:
ret i32 0
}
define ptr @func_144(ptr %p_145) {
entry:
%agg.tmp.ensured = alloca %struct.S0, align 8
call void @llvm.memcpy.p0.p0.i64(ptr %agg.tmp.ensured, ptr @g_148, i64 24, i1 true)
ret ptr %p_145
}
```
Output:
```
%struct.S0 = type { i32, i32, i64, i16 }
define noundef i32 @main() local_unnamed_addr #0 {
ret i32 0
}
define noundef i32 @func_127() local_unnamed_addr #0 {
ret i32 0
}
define ptr @func_144(ptr readnone returned %p_145) local_unnamed_addr #0 {
%agg.tmp.ensured = alloca %struct.S0, align 8
call void @llvm.memcpy.p0.p0.i64(ptr nonnull %agg.tmp.ensured, ptr @g_148, i64 24, i1 true)
ret ptr %p_145
}
declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #1
attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) }
attributes #1 = { mustprogress nocallback nofree nounwind willreturn memory(argmem: readwrite) }
```
The memory effect of `func_144` should not be `memory(none)`.
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