| Issue |
141017
|
| Summary |
[InstCombine] Miscompilation `select (fcmp nsz olt X, 0.0), -0.0, X -> select (fcmp nsz ole X, -0.0), -0.0, X`
|
| Labels |
miscompilation,
llvm:instcombine,
floating-point
|
| Assignees |
dtcxzyw
|
| Reporter |
dtcxzyw
|
Reproducer: https://alive2.llvm.org/ce/z/Uydp8F
```
define float @src(float %x) {
%cmp = fcmp nsz olt float %x, 0.0
%sel = select i1 %cmp, float -0.0, float %x
ret float %sel
}
define float @tgt(float %x) {
%.inv = fcmp nsz ole float %x, -0.000000e+00
%sel1 = select i1 %.inv, float -0.000000e+00, float %x
ret float %sel1
}
```
```
Transformation doesn't verify!
ERROR: Target's return value is more undefined
Example:
float %x = #x00000000 (+0.0)
Source:
i1 %cmp = #x0 (0)
float %sel = #x00000000 (+0.0)
Target:
i1 %.inv = #x1 (1)
float %sel1 = #x00000000 (+0.0)
Source value: #x00000000 (+0.0)
Target value: #x00000000 (+0.0)
```
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