| Issue |
77108
|
| Summary |
IV not simplified
|
| Labels |
llvm:instcombine,
missed-optimization
|
| Assignees |
|
| Reporter |
nikic
|
https://alive2.llvm.org/ce/z/hfmwgf
The following fold is not performed. Same can be done with GEPs.
```llvm
define void @src2(i64 %base, i64 %end) {
entry:
br label %loop
loop:
%iv2 = phi i64 [ %iv2.next, %loop ], [ %base, %entry ]
%iv = phi i64 [ %iv.next, %loop ], [ 0, %entry ]
call void @use.i64(i64 %iv2)
%iv.next = add nuw nsw i64 %iv, 4
%iv2.next = add i64 %base, %iv.next
%cmp = icmp eq i64 %iv.next, %end
br i1 %cmp, label %exit, label %loop
exit:
ret void
}
define void @tgt2(i64 %base, i64 %end) {
entry:
br label %loop
loop:
%iv = phi i64 [ %iv.next, %loop ], [ 0, %entry ]
%iv2 = add i64 %base, %iv
call void @use.i64(i64 %iv2)
%iv.next = add nuw nsw i64 %iv, 4
%cmp = icmp eq i64 %iv.next, %end
br i1 %cmp, label %exit, label %loop
exit:
ret void
}
```
iv2 here is basically just iv+base but written as phi(base, iv.next+base)
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