Index: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp =================================================================== --- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -1318,6 +1318,24 @@ return ExtractValueInst::Create(Call, 1, "sadd.overflow"); } +// Handle (icmp sgt smin(PosA, B) 0) -> (icmp sgt B 0) +Instruction *InstCombiner::foldICmpWithZero(ICmpInst &Cmp) { + CmpInst::Predicate Pred = Cmp.getPredicate(); + Value *X = Cmp.getOperand(0); + + if (match(Cmp.getOperand(1), m_Zero()) && Pred == ICmpInst::ICMP_SGT) { + Value *A, *B; + SelectPatternResult SPR = matchSelectPattern(X, A, B); + if (SPR.Flavor == SPF_SMIN) { + if (isKnownPositive(A, DL, 0, &AC, &Cmp, &DT)) + return new ICmpInst(Pred, B, Cmp.getOperand(1)); + if (isKnownPositive(B, DL, 0, &AC, &Cmp, &DT)) + return new ICmpInst(Pred, A, Cmp.getOperand(1)); + } + } + return nullptr; +} + // Fold icmp Pred X, C. Instruction *InstCombiner::foldICmpWithConstant(ICmpInst &Cmp) { CmpInst::Predicate Pred = Cmp.getPredicate(); @@ -1349,17 +1367,6 @@ return Res; } - // (icmp sgt smin(PosA, B) 0) -> (icmp sgt B 0) - if (C->isNullValue() && Pred == ICmpInst::ICMP_SGT) { - SelectPatternResult SPR = matchSelectPattern(X, A, B); - if (SPR.Flavor == SPF_SMIN) { - if (isKnownPositive(A, DL, 0, &AC, &Cmp, &DT)) - return new ICmpInst(Pred, B, Cmp.getOperand(1)); - if (isKnownPositive(B, DL, 0, &AC, &Cmp, &DT)) - return new ICmpInst(Pred, A, Cmp.getOperand(1)); - } - } - // FIXME: Use m_APInt to allow folds for splat constants. ConstantInt *CI = dyn_cast(Cmp.getOperand(1)); if (!CI) @@ -4462,6 +4469,10 @@ (SI->getOperand(2) == Op0 && SI->getOperand(1) == Op1)) return nullptr; + // Do this after checking for min/max to prevent infinite looping. + if (Instruction *Res = foldICmpWithZero(I)) + return Res; + // FIXME: We only do this after checking for min/max to prevent infinite // looping caused by a reverse canonicalization of these patterns for min/max. // FIXME: The organization of folds is a mess. These would naturally go into Index: llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h =================================================================== --- llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h @@ -700,6 +700,7 @@ Instruction *foldICmpInstWithConstantNotInt(ICmpInst &Cmp); Instruction *foldICmpBinOp(ICmpInst &Cmp); Instruction *foldICmpEquality(ICmpInst &Cmp); + Instruction *foldICmpWithZero(ICmpInst &Cmp); Instruction *foldICmpSelectConstant(ICmpInst &Cmp, SelectInst *Select, ConstantInt *C); Index: llvm/trunk/test/Transforms/InstCombine/minmax-fold.ll =================================================================== --- llvm/trunk/test/Transforms/InstCombine/minmax-fold.ll +++ llvm/trunk/test/Transforms/InstCombine/minmax-fold.ll @@ -507,7 +507,7 @@ ; CHECK-LABEL: @clamp_check_for_no_infinite_loop1( ; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i32 [[I:%.*]], 255 ; CHECK-NEXT: [[SEL1:%.*]] = select i1 [[CMP1]], i32 [[I]], i32 255 -; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i32 [[I]], 0 +; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i32 [[SEL1]], 0 ; CHECK-NEXT: [[RES:%.*]] = select i1 [[TMP1]], i32 [[SEL1]], i32 0 ; CHECK-NEXT: ret i32 [[RES]] ;