Index: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp =================================================================== --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -1625,11 +1625,12 @@ // jle foo // if (const BinaryOperator *BOp = dyn_cast(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 Index: llvm/trunk/test/CodeGen/X86/or-branch.ll =================================================================== --- llvm/trunk/test/CodeGen/X86/or-branch.ll +++ llvm/trunk/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 = !{} +