[PATCH] D140666: [InstCombine] combine intersection for inequality icmps

[chenglin.bi via Phabricator via llvm-commits]

bcl5980 added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp:628
 
   if (Mask & BMask_Mixed) {
     // (icmp eq (A & B), C) & (icmp eq (A & D), E)
----------------
Can we merge the code into here? It looks the logic is almost the same.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp:681-682
+
+    assert((~*ConstB & ConstC) == 0);
+    assert((~*ConstD & ConstE) == 0);
+
----------------
spatel wrote:
> Add a string message to each assert like "Expected impossible compares to be simplified".
> 
> But I'm skeptical that we can actually do that. Ie, how do we guarantee that the operands of this logic instruction were already visited before we got here? If we can't guarantee that, just bail out instead.
I think the assert should be OK. simplifyICmpInst will optimize the icmp to constant at very early time before the assert triggered.


Repository:
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  https://reviews.llvm.org/D140666/new/

https://reviews.llvm.org/D140666