| Issue |
115512
|
| Summary |
[AArch64][GlobalISel] Improve i128 mul generation
|
| Labels |
backend:AArch64,
llvm:globalisel
|
| Assignees |
|
| Reporter |
davemgreen
|
i128 multiplies under GlobalISel could be producing more madds if it reassociated the add.
https://godbolt.org/z/Wr1r5ez1G
SDAG
```
umulh x8, x0, x2
madd x8, x0, x3, x8
mul x0, x0, x2
madd x1, x1, x2, x8
ret
```
GISel
```
mul x9, x0, x3
mul x8, x0, x2
umulh x10, x0, x2
madd x9, x1, x2, x9
mov x0, x8
add x1, x9, x10
ret
```
![]()
_______________________________________________
llvm-bugs mailing list
[email protected]
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
