| Issue |
157238
|
| Summary |
[InstCombine] Wrong folding of is.fpclass + minnum
|
| Labels |
miscompilation,
llvm:instcombine,
generated by fuzzer
|
| Assignees |
dtcxzyw
|
| Reporter |
dtcxzyw
|
Reproducer: https://alive2.llvm.org/ce/z/zTqnNp
```
; bin/opt -passes=instcombine test.ll -S
define i1 @src(i32 %x) {
entry:
%or102.i.i = or i32 %x, -5938
%0 = bitcast i32 %or102.i.i to float
%1 = call float @llvm.minnum.f32(float %0, float 0.000000e+00)
%tobool106.not2.i.i = call i1 @llvm.is.fpclass.f32(float %1, i32 64)
ret i1 %tobool106.not2.i.i
}
```
```
----------------------------------------
define i1 @src(i32 %x) {
entry:
%or102.i.i = or i32 %x, 4294961358
%#0 = bitcast i32 %or102.i.i to float
%#1 = fmin float %#0, 0.000000
%tobool106.not2.i.i = is.fpclass float %#1, i32 64
ret i1 %tobool106.not2.i.i
}
=>
define i1 @src(i32 %x) nofree noundef willreturn memory(none) {
entry:
ret i1 0
}
Transformation doesn't verify!
ERROR: Value mismatch
Example:
i32 %x = #x00000000 (0)
Source:
i32 %or102.i.i = #xffffe8ce (4294961358, -5938)
float %#0 = #xffffe8ce (QNaN)
float %#1 = #x00000000 (+0.0)
i1 %tobool106.not2.i.i = #x1 (1)
Target:
Source value: #x1 (1)
Target value: #x0 (0)
Summary:
0 correct transformations
1 incorrect transformations
0 failed-to-prove transformations
0 Alive2 errors
```
![]()
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
