[PATCH] D136015: [InstCombine] Fold series of instructions into mull

[Allen zhong via Phabricator via llvm-commits]

Allen marked an inline comment as done.
Allen added inline comments.


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Comment at: llvm/lib/Transforms/InstCombine/InstructionCombining.cpp:856
+Value *InstCombinerImpl::SimplifyMull(BinaryOperator &I) {
+  if (!(I.getType()->isIntegerTy() && I.getType()->getIntegerBitWidth() == 64))
+    return nullptr;
----------------
Allen wrote:
> bcl5980 wrote:
> > This pattern can work for any types with even bit width I think, not only i64.
> The source https://godbolt.org/z/x5jMhqW8s is equel to an mull operater for two 64bits integer vaules, so it should be fold to similar assemble.
> This is the 1st step try to generate the mul, so now I only enable it with i64 as the instruction umulh
delete the checking I.getType()->getIntegerBitWidth() == 64, thanks.


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  https://reviews.llvm.org/D136015/new/

https://reviews.llvm.org/D136015