[PATCH] D52671: [InstCombine] Skip merging non-free GEP

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

Do you have perf/size numbers?

I'm sort of confused that MachineCSE doesn't trigger on your testcase, but that isn't really relevant here, I guess.



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Comment at: llvm/lib/Transforms/InstCombine/InstructionCombining.cpp:1681
+    if (isa<Instruction>(Src) && !Src->hasOneUse() &&
+        TTI.getUserCost(Src) != TargetTransformInfo::TCC_Free) {
+      BasicBlock *CurBB = GEP.getParent();
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For array GEPs, we have a check to try to make sure we aren't making a GEP more expensive (see EndsWithSequential etc.)  Maybe instead of adding a different kind of check, it would make more sense to extend the existing check to struct GEPs?


https://reviews.llvm.org/D52671