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author | Chris Lattner <sabre@nondot.org> | 2010-01-12 20:41:47 +0000 |
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committer | Chris Lattner <sabre@nondot.org> | 2010-01-12 20:41:47 +0000 |
commit | 972a46c96a06ecb0e8ce73c796c313175abe76bb (patch) | |
tree | 14b5aa7e993317c77b525e35f91b3ba727458b9b /lib/Transforms/Scalar/JumpThreading.cpp | |
parent | e234a30a282f1aaec4aa63460fe8bba6416832a8 (diff) | |
download | llvm-972a46c96a06ecb0e8ce73c796c313175abe76bb.tar.gz llvm-972a46c96a06ecb0e8ce73c796c313175abe76bb.tar.bz2 llvm-972a46c96a06ecb0e8ce73c796c313175abe76bb.tar.xz |
1) Use the new SimplifyInstructionsInBlock routine instead of the copy
in JT.
2) When cloning blocks for PHI or xor conditions, use
instsimplify to simplify the code as we go. This allows us to
squish common cases early in JT which opens up opportunities for
subsequent iterations, and allows it to completely simplify the
testcase.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93253 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/Scalar/JumpThreading.cpp')
-rw-r--r-- | lib/Transforms/Scalar/JumpThreading.cpp | 31 |
1 files changed, 14 insertions, 17 deletions
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp index edb0412bfe..9531311551 100644 --- a/lib/Transforms/Scalar/JumpThreading.cpp +++ b/lib/Transforms/Scalar/JumpThreading.cpp @@ -1341,20 +1341,7 @@ bool JumpThreading::ThreadEdge(BasicBlock *BB, // At this point, the IR is fully up to date and consistent. Do a quick scan // over the new instructions and zap any that are constants or dead. This // frequently happens because of phi translation. - BI = NewBB->begin(); - for (BasicBlock::iterator E = NewBB->end(); BI != E; ) { - Instruction *Inst = BI++; - - if (Value *V = SimplifyInstruction(Inst, TD)) { - WeakVH BIHandle(BI); - ReplaceAndSimplifyAllUses(Inst, V, TD); - if (BIHandle == 0) - BI = NewBB->begin(); - continue; - } - - RecursivelyDeleteTriviallyDeadInstructions(Inst); - } + SimplifyInstructionsInBlock(NewBB, TD); // Threaded an edge! ++NumThreads; @@ -1425,9 +1412,6 @@ bool JumpThreading::DuplicateCondBranchOnPHIIntoPred(BasicBlock *BB, // mapping and using it to remap operands in the cloned instructions. for (; BI != BB->end(); ++BI) { Instruction *New = BI->clone(); - New->setName(BI->getName()); - PredBB->getInstList().insert(OldPredBranch, New); - ValueMapping[BI] = New; // Remap operands to patch up intra-block references. for (unsigned i = 0, e = New->getNumOperands(); i != e; ++i) @@ -1436,6 +1420,19 @@ bool JumpThreading::DuplicateCondBranchOnPHIIntoPred(BasicBlock *BB, if (I != ValueMapping.end()) New->setOperand(i, I->second); } + + // If this instruction can be simplified after the operands are updated, + // just use the simplified value instead. This frequently happens due to + // phi translation. + if (Value *IV = SimplifyInstruction(New, TD)) { + delete New; + ValueMapping[BI] = IV; + } else { + // Otherwise, insert the new instruction into the block. + New->setName(BI->getName()); + PredBB->getInstList().insert(OldPredBranch, New); + ValueMapping[BI] = New; + } } // Check to see if the targets of the branch had PHI nodes. If so, we need to |