[PATCH] D41811: X86: Add pattern matching for PMADDWD

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: lib/Target/X86/X86ISelLowering.cpp:37149
+  // Helper for examining one ADD operand.
+  auto IsBuildVectorOfExtractsFromMul = [](
+      SDValue Op, ArrayRef<unsigned> ExpectedIndices, SDValue &RetMul) {
----------------
Can't you do this in a fully general manner, checking both LHS+RHS at the same time that one is the odd and the other is the even? It seems as the moment you can only check for all_odd+all_even or all_even+all_odd.


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Comment at: lib/Target/X86/X86ISelLowering.cpp:37171
+            Mul.getValueType().getVectorNumElements() !=
+                2 * ExpectedIndices.size())
+          return false;
----------------
Mul.getValueType().getVectorNumElements() != (2 * e)


https://reviews.llvm.org/D41811