| Issue |
115301
|
| Summary |
[GVN] mishandle of `phi`
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
bongjunj
|
Alive2 report: https://alive2.llvm.org/ce/z/yDrndK
```llvm
----------------------------------------
define double @fcmp_une_not_zero.2(double %x, double %y) {
entry:
%cmp = fcmp une double %y, 2.000000
br i1 %cmp, label %return, label %else
else:
br label %return
return:
%retval = phi double [ undef, %else ], [ %x, %entry ]
ret double %retval
}
=>
define double @fcmp_une_not_zero.2(double %x, double %y) {
entry:
%cmp = fcmp une double %y, 2.000000
br i1 %cmp, label %return, label %else
else:
br label %return
return:
ret double %x
}
Transformation doesn't verify!
ERROR: Target is more poisonous than source
Example:
double %x = poison
double %y = #x4000000000000000 (2)
Source:
i1 %cmp = #x0 (0)
>> Jump to %else
>> Jump to %return
double %retval = #x0000000000000000 (+0.0) [based on undef value]
Target:
i1 %cmp = #x0 (0)
>> Jump to %else
>> Jump to %return
Source value: #x0000000000000000 (+0.0)
Target value: poison
Summary:
0 correct transformations
1 incorrect transformations
0 failed-to-prove transformations
0 Alive2 errors
```
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