| Issue |
55490
|
| Summary |
miscompile from arm64 backend
|
| Labels |
backend:AArch64,
llvm:codegen,
miscompilation
|
| Assignees |
|
| Reporter |
regehr
|
here's a function that needs to return true:
```llvm
define i1 @f() {
%1 = sub i4 -6, -8
%2 = icmp ult i4 %1, 3
ret i1 %2
}
```
however, since the 14 release the arm64 backend got a regression causing it to return false:
```console
regehr@john-home:~/tmp$ ~/clang+llvm-14.0.0-x86_64-linux-gnu-ubuntu-18.04/bin/llc foo.ll -o - -march=arm64
.text
.file "foo.ll"
.globl f // -- Begin function f
.p2align 2
.type f,@function
f: // @f
.cfi_startproc
// %bb.0:
mov w0, #1
ret
.Lfunc_end0:
.size f, .Lfunc_end0-f
.cfi_endproc
// -- End function
.section ".note.GNU-stack","",@progbits
regehr@john-home:~/tmp$ ~/llvm-project/for-alive/bin/llc foo.ll -o - -march=arm64
.text
.file "foo.ll"
.globl f // -- Begin function f
.p2align 2
.type f,@function
f: // @f
.cfi_startproc
// %bb.0:
mov w0, wzr
ret
.Lfunc_end0:
.size f, .Lfunc_end0-f
.cfi_endproc
// -- End function
.section ".note.GNU-stack","",@progbits
regehr@john-home:~/tmp$
```
cc @ornata @nunoplopes @ryan-berger @nbushehri @zhengyang92 @aqjune @Hatsunespica
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