diff options
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineCompares.cpp | 49 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/icmp.ll | 52 |
2 files changed, 101 insertions, 0 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp index 415ee9f..4d5fa87 100644 --- a/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -2487,6 +2487,55 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { return new ICmpInst(Pred, Y, Z); } + // icmp slt (X + -1), Y -> icmp sle X, Y + if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_SLT && + match(B, m_AllOnes())) + return new ICmpInst(CmpInst::ICMP_SLE, A, Op1); + + // icmp sge (X + -1), Y -> icmp sgt X, Y + if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_SGE && + match(B, m_AllOnes())) + return new ICmpInst(CmpInst::ICMP_SGT, A, Op1); + + // icmp sle (X + 1), Y -> icmp slt X, Y + if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_SLE && + match(B, m_One())) + return new ICmpInst(CmpInst::ICMP_SLT, A, Op1); + + // icmp sgt (X + 1), Y -> icmp sge X, Y + if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_SGT && + match(B, m_One())) + return new ICmpInst(CmpInst::ICMP_SGE, A, Op1); + + // if C1 has greater magnitude than C2: + // icmp (X + C1), (Y + C2) -> icmp (X + C3), Y + // s.t. C3 = C1 - C2 + // + // if C2 has greater magnitude than C1: + // icmp (X + C1), (Y + C2) -> icmp X, (Y + C3) + // s.t. C3 = C2 - C1 + if (A && C && NoOp0WrapProblem && NoOp1WrapProblem && + (BO0->hasOneUse() || BO1->hasOneUse()) && !I.isUnsigned()) + if (ConstantInt *C1 = dyn_cast<ConstantInt>(B)) + if (ConstantInt *C2 = dyn_cast<ConstantInt>(D)) { + const APInt &AP1 = C1->getValue(); + const APInt &AP2 = C2->getValue(); + if (AP1.isNegative() == AP2.isNegative()) { + APInt AP1Abs = C1->getValue().abs(); + APInt AP2Abs = C2->getValue().abs(); + if (AP1Abs.uge(AP2Abs)) { + ConstantInt *C3 = Builder->getInt(AP1 - AP2); + Value *NewAdd = Builder->CreateNSWAdd(A, C3); + return new ICmpInst(Pred, NewAdd, C); + } else { + ConstantInt *C3 = Builder->getInt(AP2 - AP1); + Value *NewAdd = Builder->CreateNSWAdd(C, C3); + return new ICmpInst(Pred, A, NewAdd); + } + } + } + + // Analyze the case when either Op0 or Op1 is a sub instruction. // Op0 = A - B (or A and B are null); Op1 = C - D (or C and D are null). A = 0; B = 0; C = 0; D = 0; diff --git a/test/Transforms/InstCombine/icmp.ll b/test/Transforms/InstCombine/icmp.ll index 446c0e0..28fa33b 100644 --- a/test/Transforms/InstCombine/icmp.ll +++ b/test/Transforms/InstCombine/icmp.ll @@ -886,3 +886,55 @@ define i1 @icmp_mul0_ne0(i32 %x) { %cmp = icmp ne i32 %mul, 0 ret i1 %cmp } + +; CHECK: @icmp_sub1_sge +; CHECK-NEXT: icmp sgt i32 %x, %y +define i1 @icmp_sub1_sge(i32 %x, i32 %y) { + %sub = add nsw i32 %x, -1 + %cmp = icmp sge i32 %sub, %y + ret i1 %cmp +} + +; CHECK: @icmp_add1_sgt +; CHECK-NEXT: icmp sge i32 %x, %y +define i1 @icmp_add1_sgt(i32 %x, i32 %y) { + %add = add nsw i32 %x, 1 + %cmp = icmp sgt i32 %add, %y + ret i1 %cmp +} + +; CHECK: @icmp_sub1_slt +; CHECK-NEXT: icmp sle i32 %x, %y +define i1 @icmp_sub1_slt(i32 %x, i32 %y) { + %sub = add nsw i32 %x, -1 + %cmp = icmp slt i32 %sub, %y + ret i1 %cmp +} + +; CHECK: @icmp_add1_sle +; CHECK-NEXT: icmp slt i32 %x, %y +define i1 @icmp_add1_sle(i32 %x, i32 %y) { + %add = add nsw i32 %x, 1 + %cmp = icmp sle i32 %add, %y + ret i1 %cmp +} + +; CHECK: @icmp_add20_sge_add57 +; CHECK-NEXT: [[ADD:%[a-z0-9]+]] = add nsw i32 %y, 37 +; CHECK-NEXT: icmp sle i32 [[ADD]], %x +define i1 @icmp_add20_sge_add57(i32 %x, i32 %y) { + %1 = add nsw i32 %x, 20 + %2 = add nsw i32 %y, 57 + %cmp = icmp sge i32 %1, %2 + ret i1 %cmp +} + +; CHECK: @icmp_sub57_sge_sub20 +; CHECK-NEXT: [[SUB:%[a-z0-9]+]] = add nsw i32 %x, -37 +; CHECK-NEXT: icmp sge i32 [[SUB]], %y +define i1 @icmp_sub57_sge_sub20(i32 %x, i32 %y) { + %1 = add nsw i32 %x, -57 + %2 = add nsw i32 %y, -20 + %cmp = icmp sge i32 %1, %2 + ret i1 %cmp +} |