diff --git a/llvm/lib/Analysis/BranchProbabilityInfo.cpp b/llvm/lib/Analysis/BranchProbabilityInfo.cpp index 7cdf828c2f4b..86560ca33d0c 100644 --- a/llvm/lib/Analysis/BranchProbabilityInfo.cpp +++ b/llvm/lib/Analysis/BranchProbabilityInfo.cpp @@ -398,10 +398,24 @@ bool BranchProbabilityInfo::calcZeroHeuristics(BasicBlock *BB) { // InstCombine canonicalizes X <= 0 into X < 1. // X <= 0 -> Unlikely isProb = false; - } else if (CV->isAllOnesValue() && CI->getPredicate() == CmpInst::ICMP_SGT) { - // InstCombine canonicalizes X >= 0 into X > -1. - // X >= 0 -> Likely - isProb = true; + } else if (CV->isAllOnesValue()) { + switch (CI->getPredicate()) { + case CmpInst::ICMP_EQ: + // X == -1 -> Unlikely + isProb = false; + break; + case CmpInst::ICMP_NE: + // X != -1 -> Likely + isProb = true; + break; + case CmpInst::ICMP_SGT: + // InstCombine canonicalizes X >= 0 into X > -1. + // X >= 0 -> Likely + isProb = true; + break; + default: + return false; + } } else { return false; } diff --git a/llvm/test/Analysis/BranchProbabilityInfo/basic.ll b/llvm/test/Analysis/BranchProbabilityInfo/basic.ll index c6e1bde81dff..05cb31dca0ee 100644 --- a/llvm/test/Analysis/BranchProbabilityInfo/basic.ll +++ b/llvm/test/Analysis/BranchProbabilityInfo/basic.ll @@ -173,3 +173,42 @@ exit: %ret = phi i32 [ %val4, %then ], [ %val3, %else ] ret i32 %ret } + +define i32 @zero1(i32 %i, i32 %a, i32 %b) { +; CHECK: Printing analysis {{.*}} for function 'zero1' +entry: + %cond = icmp eq i32 %i, 0 + br i1 %cond, label %then, label %else +; CHECK: edge entry -> then probability is 12 / 32 +; CHECK: edge entry -> else probability is 20 / 32 + +then: + br label %exit + +else: + br label %exit + +exit: + %result = phi i32 [ %a, %then ], [ %b, %else ] + ret i32 %result +} + +define i32 @zero2(i32 %i, i32 %a, i32 %b) { +; CHECK: Printing analysis {{.*}} for function 'zero2' +entry: + %cond = icmp ne i32 %i, -1 + br i1 %cond, label %then, label %else +; CHECK: edge entry -> then probability is 20 / 32 +; CHECK: edge entry -> else probability is 12 / 32 + +then: + br label %exit + +else: + br label %exit + +exit: + %result = phi i32 [ %a, %then ], [ %b, %else ] + ret i32 %result +} +