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use "unpredictable" metadata in fast-isel when splitting compares

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This patch uses the metadata defined in D12341 to avoid creating an unpredictable branch.

Differential Revision: http://reviews.llvm.org/D12342

llvm-svn: 246692
This commit is contained in:
Sanjay Patel
2015-09-02 19:23:23 +00:00
parent fff7c6dc73
commit 42574203e5
2 changed files with 56 additions and 1 deletions
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5
llvm/lib/CodeGen/CodeGenPrepare.cpp
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@@ -4667,6 +4667,10 @@ bool CodeGenPrepare::splitBranchCondition(Function &F) {
if (!match(BB.getTerminator(), m_Br(m_OneUse(m_BinOp(LogicOp)), TBB, FBB)))
continue;
auto *Br1 = cast<BranchInst>(BB.getTerminator());
if (Br1->getMetadata(LLVMContext::MD_unpredictable))
continue;
unsigned Opc;
Value *Cond1, *Cond2;
if (match(LogicOp, m_And(m_OneUse(m_Value(Cond1)),
@@ -4693,7 +4697,6 @@ bool CodeGenPrepare::splitBranchCondition(Function &F) {
// Update original basic block by using the first condition directly by the
// branch instruction and removing the no longer needed and/or instruction.
auto *Br1 = cast<BranchInst>(BB.getTerminator());
Br1->setCondition(Cond1);
LogicOp->eraseFromParent();