[PATCH] D97160: [DAGCombiner] Optimize SMULO/UMULO if we can prove that overflow is impossible.

Craig Topper via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue Feb 23 12:16:43 PST 2021


craig.topper added inline comments.


================
Comment at: llvm/test/CodeGen/X86/xmulo.ll:11
+; CHECK-NEXT:    xorl %edx, %edx
 ; CHECK-NEXT:    retq
   %1 = call {i64, i1} @llvm.umul.with.overflow.i64(i64 9, i64 8)
----------------
craig.topper wrote:
> RKSimon wrote:
> > Are we missing constant folding?
> Looks like it. Doesn't look like we have it for ADDO either.
Is that a blocker for this patch?


Repository:
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  https://reviews.llvm.org/D97160/new/

https://reviews.llvm.org/D97160



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