| Issue |
140994
|
| Summary |
[InstCombine] `(fcmp une T, F) ? T : F --> T` should not rely on the nsz flag on fcmp
|
| Labels |
miscompilation,
llvm:instcombine,
floating-point
|
| Assignees |
dtcxzyw
|
| Reporter |
dtcxzyw
|
Reproducer: https://alive2.llvm.org/ce/z/_FgncC
```
define double @src(double %x, double %y) {
%cmp = fcmp nsz une double %x, %y
%cond = select i1 %cmp, double %x, double %y
ret double %cond
}
define double @tgt(double returned %x, double %y) {
ret double %x
}
```
```
Transformation doesn't verify!
ERROR: Value mismatch
Example:
double %x = #x8000000000000000 (-0.0)
double %y = #x0000000000000000 (+0.0)
Source:
i1 %cmp = #x0 (0)
double %cond = #x0000000000000000 (+0.0)
Target:
Source value: #x0000000000000000 (+0.0)
Target value: #x8000000000000000 (-0.0)
```
`nsz` flag should not be propagated from fcmp into select.
![]()
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
