[PATCH] D34184: [InstCombine] Teach foldSelectICmpAndOr to recognize (select (icmp slt (trunc (X)), 0), Y, (or Y, C2))

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

The enhancement looks right, but I'm worried that the existing transform can increase the instruction count if any of the pieces in the pattern have more than one use. Are we missing m_OneUse() in some/all of the matchers?



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Comment at: lib/Transforms/InstCombine/InstCombineSelect.cpp:365
+    // Insert the and instruction.
+    V = Builder->CreateAnd(X, ConstantInt::get(X->getType(), APInt::getOneBitSet(X->getType()->getScalarSizeInBits(), C1Log)));
+  } else {
----------------
Formatting.


https://reviews.llvm.org/D34184