| Issue |
137810
|
| Summary |
[MemCpyOpt or GVN] Load source from memcpy
|
| Labels |
llvm:optimizations,
missed-optimization
|
| Assignees |
dianqk
|
| Reporter |
dianqk
|
The following IR can be transformed from `load i24, ptr %dest` to `load i24, ptr %src` so that we can know `%arg` equals `%arg2`.
```llvm
define noundef i1 @wombat(ptr align 4 %src) {
bb:
%dest = alloca [3 x i8], align 4
%arg = load i24, ptr %src, align 4
call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 4 dereferenceable(3) %dest, ptr noundef nonnull align 4 dereferenceable(3) %src, i64 3, i1 false)
%arg2 = load i24, ptr %dest, align 4
%select = icmp eq i24 %arg, %arg2
call void @snork(ptr nonnull %dest)
ret i1 %select
}
declare void @snork(ptr)
declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg)
```
![]()
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
