[PATCH] D132700: [DSE] Add value type checks for masked store candidates in Dead Store Elimination

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


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Comment at: llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp:252
+    VectorType *DeadTy = cast<VectorType>(DeadII->getArgOperand(0)->getType());
+    if (KillingTy->getScalarSizeInBits() != DeadTy->getScalarSizeInBits())
+      return OW_Unknown;
----------------
mcberg2021 wrote:
> fhahn wrote:
> > This should be fine if `KillingTy->getScalarSizeInBits >= DeadTy->getScalarSizeInBits()`, right? I might have missed it, but t looks like there's no test case like the one @mcberg2021 mentioned above?
> That too should work.  I will update for the subsumption case. However I would like to leave the mask decomposition support for a later change.
If the mask is unknown then the store is not writing contiguous bytes. There can be gaps. So it is not sufficient to check that scalar size is larger.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D132700/new/

https://reviews.llvm.org/D132700