diff options
| -rw-r--r-- | llvm/lib/CodeGen/CodeGenPrepare.cpp | 8 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/cmov-into-branch.ll | 14 |
2 files changed, 19 insertions, 3 deletions
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp index b5ffbeb3dec..56a1639c8e9 100644 --- a/llvm/lib/CodeGen/CodeGenPrepare.cpp +++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp @@ -4559,9 +4559,11 @@ static bool isFormingBranchFromSelectProfitable(const TargetTransformInfo *TTI, if (SI->extractProfMetadata(TrueWeight, FalseWeight)) { uint64_t Max = std::max(TrueWeight, FalseWeight); uint64_t Sum = TrueWeight + FalseWeight; - auto Probability = BranchProbability::getBranchProbability(Max, Sum); - if (Probability > TLI->getPredictableBranchThreshold()) - return true; + if (Sum != 0) { + auto Probability = BranchProbability::getBranchProbability(Max, Sum); + if (Probability > TLI->getPredictableBranchThreshold()) + return true; + } } CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition()); diff --git a/llvm/test/CodeGen/X86/cmov-into-branch.ll b/llvm/test/CodeGen/X86/cmov-into-branch.ll index 35c1d3498a5..acb5a2bb51f 100644 --- a/llvm/test/CodeGen/X86/cmov-into-branch.ll +++ b/llvm/test/CodeGen/X86/cmov-into-branch.ll @@ -114,8 +114,22 @@ define i32 @weighted_select3(i32 %a, i32 %b) { ret i32 %sel } +; Weightlessness is no reason to die. +define i32 @unweighted_select(i32 %a, i32 %b) { +; CHECK-LABEL: unweighted_select: +; CHECK: # BB#0: +; CHECK-NEXT: testl %edi, %edi +; CHECK-NEXT: cmovnel %edi, %esi +; CHECK-NEXT: movl %esi, %eax +; CHECK-NEXT: retq +; + %cmp = icmp ne i32 %a, 0 + %sel = select i1 %cmp, i32 %a, i32 %b, !prof !3 + ret i32 %sel +} !0 = !{!"branch_weights", i32 1, i32 99} !1 = !{!"branch_weights", i32 1, i32 100} !2 = !{!"branch_weights", i32 100, i32 1} +!3 = !{!"branch_weights", i32 0, i32 0} |
