diff options
Diffstat (limited to 'lib/Transforms/Utils/SimplifyCFG.cpp')
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index c72806b9e2..605855d176 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -965,6 +965,12 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *BB1) { if (BB1->size() != 2) return false; + // Be conservative for now. FP select instruction can often be expensive. + Value *BrCond = BI->getCondition(); + if (isa<Instruction>(BrCond) && + cast<Instruction>(BrCond)->getOpcode() == Instruction::FCmp) + return false; + // If BB1 is actually on the false edge of the conditional branch, remember // to swap the select operands later. bool Invert = false; @@ -1029,8 +1035,7 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *BB1) { BasicBlock::iterator InsertPos = BI; if (InsertPos != BIParent->begin()) --InsertPos; - if (InsertPos->getOpcode() == Instruction::ICmp || - InsertPos->getOpcode() == Instruction::FCmp) + if (InsertPos == BrCond) BIParent->getInstList().splice(InsertPos, BB1->getInstList(), I); else BIParent->getInstList().splice(BI, BB1->getInstList(), I); @@ -1039,10 +1044,10 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *BB1) { // false value is the previously determined FalseV. SelectInst *SI; if (Invert) - SI = SelectInst::Create(BI->getCondition(), FalseV, I, + SI = SelectInst::Create(BrCond, FalseV, I, FalseV->getName() + "." + I->getName(), BI); else - SI = SelectInst::Create(BI->getCondition(), I, FalseV, + SI = SelectInst::Create(BrCond, I, FalseV, I->getName() + "." + FalseV->getName(), BI); // Make the PHI node use the select for all incoming values for "then" and |