Index: lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp =================================================================== --- lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -1598,7 +1598,8 @@ // jle foo // if (const BinaryOperator *BOp = dyn_cast(CondVal)) { - if (!DAG.getTargetLoweringInfo().isJumpExpensive() && + if (!I.getMetadata(LLVMContext::MD_unpredictable) && + !DAG.getTargetLoweringInfo().isJumpExpensive() && BOp->hasOneUse() && (BOp->getOpcode() == Instruction::And || BOp->getOpcode() == Instruction::Or)) { FindMergedConditions(BOp, Succ0MBB, Succ1MBB, BrMBB, BrMBB, Index: test/CodeGen/X86/or-branch.ll =================================================================== --- test/CodeGen/X86/or-branch.ll +++ test/CodeGen/X86/or-branch.ll @@ -1,5 +1,5 @@ -; RUN: llc < %s -mtriple=i386-unknown-unknown -jump-is-expensive=0 | FileCheck %s --check-prefix=JUMP2 -; RUN: llc < %s -mtriple=i386-unknown-unknown -jump-is-expensive=1 | FileCheck %s --check-prefix=JUMP1 +; RUN: llc < %s -mtriple=i386-unknown-unknown -jump-is-expensive=0 | FileCheck %s --check-prefix=JUMP2 --check-prefix=CHECK +; RUN: llc < %s -mtriple=i386-unknown-unknown -jump-is-expensive=1 | FileCheck %s --check-prefix=JUMP1 --check-prefix=CHECK define void @foo(i32 %X, i32 %Y, i32 %Z) nounwind { ; JUMP2-LABEL: foo: @@ -25,4 +25,30 @@ ret void } +; If the branch is unpredictable, don't add another branch +; regardless of whether they are expensive or not. + +define void @unpredictable(i32 %X, i32 %Y, i32 %Z) nounwind { +; CHECK-LABEL: unpredictable: +; CHECK-DAG: sete +; CHECK-DAG: setl +; CHECK: orb +; CHECK: jne +entry: + %tmp1 = icmp eq i32 %X, 0 + %tmp3 = icmp slt i32 %Y, 5 + %tmp4 = or i1 %tmp3, %tmp1 + br i1 %tmp4, label %cond_true, label %UnifiedReturnBlock, !unpredictable !0 + +cond_true: + %tmp5 = tail call i32 (...) @bar( ) + ret void + +UnifiedReturnBlock: + ret void +} + declare i32 @bar(...) + +!0 = !{} +