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| author | Sanjay Patel <spatel@rotateright.com> | 2017-09-20 22:31:35 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2017-09-20 22:31:35 +0000 |
| commit | 73811a152a24a8ed6fbc0ec608ec04bc95db4c7d (patch) | |
| tree | d13f4fe3816ecaf35ac0ae6183609d972ea700d0 /llvm/lib/Transforms/Utils/SimplifyCFG.cpp | |
| parent | bb8636477d1cc52ad777dfa3cc9548832eb42003 (diff) | |
| download | bcm5719-llvm-73811a152a24a8ed6fbc0ec608ec04bc95db4c7d.tar.gz bcm5719-llvm-73811a152a24a8ed6fbc0ec608ec04bc95db4c7d.zip | |
[SimplifyCFG] don't create a no-op subtract
I noticed this inefficiency while investigating PR34603:
https://bugs.llvm.org/show_bug.cgi?id=34603
This fix will likely push another bug (we don't maintain state of 'LateSimplifyCFG')
into hiding, but I'll try to clean that up with a follow-up patch anyway.
llvm-svn: 313829
Diffstat (limited to 'llvm/lib/Transforms/Utils/SimplifyCFG.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index 52e07e049a0..290f4151c0a 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -5275,8 +5275,12 @@ static bool SwitchToLookupTable(SwitchInst *SI, IRBuilder<> &Builder, // Compute the table index value. Builder.SetInsertPoint(SI); - Value *TableIndex = - Builder.CreateSub(SI->getCondition(), MinCaseVal, "switch.tableidx"); + Value *TableIndex; + if (MinCaseVal->isNullValue()) + TableIndex = SI->getCondition(); + else + TableIndex = Builder.CreateSub(SI->getCondition(), MinCaseVal, + "switch.tableidx"); // Compute the maximum table size representable by the integer type we are // switching upon. |
