| Issue |
124267
|
| Summary |
[ValueTracking] miscompile in samesign compare
|
| Labels |
miscompilation,
llvm:optimizations
|
| Assignees |
DianQK
|
| Reporter |
DianQK
|
#122590 and #122700 miscompile the following code:
```llvm
define i1 @src(i8 %L0, i8 %L1, i1 %V) {
%LHS = icmp samesign ugt i8 %L0, %L1
%R0 = sub nsw i8 %L0, %L1
%RHS = icmp ult i8 %R0, -1
br i1 %LHS, label %LHS_true, label %LHS_false
LHS_true:
br label %EXIT
LHS_false:
br label %EXIT
EXIT:
%RET = phi i1 [ %RHS, %LHS_true ], [ %V, %LHS_false ]
ret i1 %RET
}
```
`%RHS` should be 1: https://alive2.llvm.org/ce/z/RscAzy.
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