| Issue |
107946
|
| Summary |
[LoongArch] Redundant sext after 32-bit signed divisions
|
| Labels |
missed-optimization,
backend:loongarch,
llvm:SelectionDAG
|
| Assignees |
|
| Reporter |
dtcxzyw
|
```
; bin/llc -mtriple=loongarch64 test.ll -o -
define signext i32 @sdiv_si32_ui32_ui32(i32 %a, i32 %b) {
entry:
%r = sdiv i32 %a, %b
ret i32 %r
}
```
```
; LA64-LABEL: sdiv_si32_ui32_ui32:
; LA64: # %bb.0: # %entry
; LA64-NEXT: addi.w $a1, $a1, 0
; LA64-NEXT: addi.w $a0, $a0, 0
; LA64-NEXT: div.d $a0, $a0, $a1
; LA64-NEXT: addi.w $a0, $a0, 0
; LA64-NEXT: ret
```
`div.d + addi.w` can be folded into `div.w` since both the divisor and dividend are 32-bit sign-extended.
See https://github.com/llvm/llvm-project/pull/107432/files#r1747088467 for more details.
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