[PATCH] D52002: Switch optimization for known maximum switch values

[Hans Wennborg via Phabricator via llvm-commits]

hans added a comment.

This is looking pretty good, so I'd suggest start writing tests. For testing, take a look at test/CodeGen/X86/switch.ll

I think we could also exploit unreachable default for the other lowering strategies (bit-tests, straight comparisons and binary search tree), but that can be done in later patches.



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Comment at: lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp:9452
+              isa<UnreachableInst>(SI->getDefaultDest()->getFirstNonPHIOrDbg());
+  bool OmitRangeCheck = UnreachableDefault  &&  SI->getNumCases() > 0;
   JumpTable JT(-1U, JTI, JumpTableMBB, nullptr);
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There seems to be an extra space between "Default" and "&&". Also, why do we need the SI->getNumCases() check?


https://reviews.llvm.org/D52002