| Issue |
89500
|
| Summary |
[InstCombine] Miscompilation with poison vectors in `src_and_eq_C_xor_OrAndNotC `
|
| Labels |
miscompilation,
llvm:instcombine
|
| Assignees |
|
| Reporter |
dtcxzyw
|
Alive2: https://alive2.llvm.org/ce/z/yB3oAx
```
define <2 x i32> @src_and_eq_C_xor_OrAndNotC(<2 x i32> %0, <2 x i32> %1, <2 x i32> %2) {
entry:
%and = and <2 x i32> %1, %0
%cmp = icmp eq <2 x i32> %and, %2
%xor = xor <2 x i32> %1, %0
%or = or <2 x i32> %1, %0
%not = xor <2 x i32> %2, <i32 -1, i32 poison>
%and1 = and <2 x i32> %or, %not
%cond = select <2 x i1> %cmp, <2 x i32> %xor, <2 x i32> %and1
ret <2 x i32> %cond
}
```
```
----------------------------------------
define <2 x i32> @src_and_eq_C_xor_OrAndNotC(<2 x i32> %#0, <2 x i32> %#1, <2 x i32> %#2) {
entry:
%and = and <2 x i32> %#1, %#0
%cmp = icmp eq <2 x i32> %and, %#2
%xor = xor <2 x i32> %#1, %#0
%or = or <2 x i32> %#1, %#0
%not = xor <2 x i32> %#2, { 4294967295, poison }
%and1 = and <2 x i32> %or, %not
%cond = select <2 x i1> %cmp, <2 x i32> %xor, <2 x i32> %and1
ret <2 x i32> %cond
}
=>
define <2 x i32> @src_and_eq_C_xor_OrAndNotC(<2 x i32> %#0, <2 x i32> %#1, <2 x i32> %#2) nofree willreturn memory(none) {
entry:
%or = or <2 x i32> %#1, %#0
%not = xor <2 x i32> %#2, { 4294967295, poison }
%and1 = and <2 x i32> %or, %not
ret <2 x i32> %and1
}
Transformation doesn't verify!
ERROR: Target is more poisonous than source
Example:
<2 x i32> %#0 = < poison, #x00000000 (0) >
<2 x i32> %#1 = < poison, #x00000000 (0) >
<2 x i32> %#2 = < poison, #x00000000 (0) >
Source:
<2 x i32> %and = < poison, #x00000000 (0) >
<2 x i1> %cmp = < poison, #x1 (1) >
<2 x i32> %xor = < poison, #x00000000 (0) >
<2 x i32> %or = < poison, #x00000000 (0) >
<2 x i32> %not = < poison, poison >
<2 x i32> %and1 = < poison, poison >
<2 x i32> %cond = < poison, #x00000000 (0) >
Target:
<2 x i32> %or = < poison, #x00000000 (0) >
<2 x i32> %not = < poison, poison >
<2 x i32> %and1 = < poison, poison >
Source value: < poison, #x00000000 (0) >
Target value: < poison, poison >
Summary:
0 correct transformations
1 incorrect transformations
0 failed-to-prove transformations
0 Alive2 errors
```
cc @nikic
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