[PATCH] D78272: [PowerPC] DAG Combine to transform shifts into multiply-high

[Amy Kwan via Phabricator via llvm-commits]

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


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Comment at: llvm/lib/Target/PowerPC/PPCISelLowering.cpp:15918
+  // performed by the type legalizer.
+  if (Subtarget.isPPC64() && DCI.isBeforeLegalize())
+    if (SDValue MULH = combineShifttoMULH(N, DCI.DAG, *this, Subtarget))
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lebedev.ri wrote:
> This doesn't look like the best check for this.
> Do we not want this transform in general, is it expected to be pessimizing somewhere?
> Then i'd expect it to be a TLI hook.
I actually realize now after doing some testing that it may be better to remove this check and to run this transformation in other passes, as well. I will update the patch to reflect this. Thanks for reviewing. 


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https://reviews.llvm.org/D78272