[PATCH] D33186: [InstCombine] Canonicalize clamp of float types to minmax in fast mode.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


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Comment at: llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp:1326
+      bool IsCastNeeded = LHS->getType()->getPrimitiveSizeInBits() !=
+                              SelType->getPrimitiveSizeInBits();
+      Value *CmpLHS = cast<CmpInst>(CondVal)->getOperand(0);
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This is very suspicious.

The way the implementation of matchSelectPattern is written, CastOp is uninitialized if the type of the compare matches the type of the select; otherwise, it's set to whatever cast we looked through.  That cast might not be a cast which changes the size of the type; it could bit a BitCast/FPToUI/etc.

I'd like to see a few testcases which cover the situations where we insert casts.


https://reviews.llvm.org/D33186