use "unpredictable" metadata in SelectionDAG when splitting compares
This patch uses the metadata defined in D12341 to avoid creating an unpredictable branch.
Differential Revision: http://reviews.llvm.org/D12343
llvm-svn: 246691
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 997fa1a..7c1706f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1625,11 +1625,12 @@
// jle foo
//
if (const BinaryOperator *BOp = dyn_cast<BinaryOperator>(CondVal)) {
- if (!DAG.getTargetLoweringInfo().isJumpExpensive() &&
- BOp->hasOneUse() && (BOp->getOpcode() == Instruction::And ||
- BOp->getOpcode() == Instruction::Or)) {
+ Instruction::BinaryOps Opcode = BOp->getOpcode();
+ if (!DAG.getTargetLoweringInfo().isJumpExpensive() && BOp->hasOneUse() &&
+ !I.getMetadata(LLVMContext::MD_unpredictable) &&
+ (Opcode == Instruction::And || Opcode == Instruction::Or)) {
FindMergedConditions(BOp, Succ0MBB, Succ1MBB, BrMBB, BrMBB,
- BOp->getOpcode(), getEdgeWeight(BrMBB, Succ0MBB),
+ Opcode, getEdgeWeight(BrMBB, Succ0MBB),
getEdgeWeight(BrMBB, Succ1MBB));
// If the compares in later blocks need to use values not currently
// exported from this block, export them now. This block should always