| Issue |
113992
|
| Summary |
Wrong substitution of a PHI node
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
bongjunj
|
Alive2 report: https://alive2.llvm.org/ce/z/89TX9n
```llvm
----------------------------------------
define i32 @sub_const_incoming0.2(i1 %b, i32 %x, i32 %y) {
entry:
br i1 %b, label %if, label %then
if:
br label %then
then:
%p0 = phi i32 [ 42, %if ], [ %x, %entry ]
%p1 = phi i32 [ undef, %if ], [ %y, %entry ]
%r = sub i32 %p1, %p0
ret i32 %r
}
=>
define i32 @sub_const_incoming0.2(i1 %b, i32 %x, i32 %y) {
entry:
br i1 %b, label %if, label %then
if:
br label %then
then:
%p0 = phi i32 [ 42, %if ], [ %x, %entry ]
%r = sub i32 %y, %p0
ret i32 %r
}
Transformation doesn't verify!
ERROR: Target is more poisonous than source
Example:
i1 %b = #x1 (1)
i32 %x = poison
i32 %y = poison
Source:
>> Jump to %if
>> Jump to %then
i32 %p0 = #x0000002a (42)
i32 %p1 = #x00000000 (0) [based on undef value]
i32 %r = #xffffffd6 (4294967254, -42)
Target:
>> Jump to %if
>> Jump to %then
i32 %p0 = #x0000002a (42)
i32 %r = poison
Source value: #xffffffd6 (4294967254, -42)
Target value: poison
Summary:
0 correct transformations
1 incorrect transformations
0 failed-to-prove transformations
0 Alive2 errors
```
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