diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 24 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/compare-udiv.ll | 91 |
2 files changed, 112 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index 28a5bd80236..6ed94cda342 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -2093,8 +2093,28 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, break; } - case Instruction::SDiv: case Instruction::UDiv: + if (ConstantInt *DivLHS = dyn_cast<ConstantInt>(LHSI->getOperand(0))) { + Value *X = LHSI->getOperand(1); + APInt C1 = RHS->getValue(); + APInt C2 = DivLHS->getValue(); + assert(C2 != 0 && "udiv 0, X should have been simplified already."); + // (icmp ugt (udiv C2, X), C1) -> (icmp ule X, C2/(C1+1)) + if (ICI.getPredicate() == ICmpInst::ICMP_UGT) { + assert(!C1.isMaxValue() && + "icmp ugt X, UINT_MAX should have been simplified already."); + return new ICmpInst(ICmpInst::ICMP_ULE, X, + ConstantInt::get(X->getType(), C2.udiv(C1 + 1))); + } + // (icmp ult (udiv C2, X), C1) -> (icmp ugt X, C2/C1) + if (ICI.getPredicate() == ICmpInst::ICMP_ULT) { + assert(C1 != 0 && "icmp ult X, 0 should have been simplified already."); + return new ICmpInst(ICmpInst::ICMP_UGT, X, + ConstantInt::get(X->getType(), C2.udiv(C1))); + } + } + // fall-through + case Instruction::SDiv: // Fold: icmp pred ([us]div X, C1), C2 -> range test // Fold this div into the comparison, producing a range check. // Determine, based on the divide type, what the range is being @@ -2105,8 +2125,6 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, if (Instruction *R = FoldICmpDivCst(ICI, cast<BinaryOperator>(LHSI), DivRHS)) return R; - // FIXME: Handle (icmp ugt (udiv i32 CI2, A), CI) and - // (icmp ult (udiv i32 CI2, A), CI). break; case Instruction::Sub: { diff --git a/llvm/test/Transforms/InstCombine/compare-udiv.ll b/llvm/test/Transforms/InstCombine/compare-udiv.ll index d919d77a5b2..140f9b52130 100644 --- a/llvm/test/Transforms/InstCombine/compare-udiv.ll +++ b/llvm/test/Transforms/InstCombine/compare-udiv.ll @@ -39,3 +39,94 @@ define i1 @test5(i32 %d) { %cmp1 = icmp ne i32 %div, 0 ret i1 %cmp1 } + +; CHECK-LABEL: @test6 +; CHECK: %cmp1 = icmp ult i32 %d, 6 +define i1 @test6(i32 %d) { + %div = udiv i32 5, %d + %cmp1 = icmp ugt i32 %div, 0 + ret i1 %cmp1 +} + +; (icmp ugt (udiv C1, X), C1) -> false. +; CHECK-LABEL: @test7 +; CHECK: ret i1 false +define i1 @test7(i32 %d) { + %div = udiv i32 8, %d + %cmp1 = icmp ugt i32 %div, 8 + ret i1 %cmp1 +} + +; CHECK-LABEL: @test8 +; CHECK: %cmp1 = icmp ult i32 %d, 2 +define i1 @test8(i32 %d) { + %div = udiv i32 4, %d + %cmp1 = icmp ugt i32 %div, 3 + ret i1 %cmp1 +} + +; CHECK-LABEL: @test9 +; CHECK: %cmp1 = icmp ult i32 %d, 2 +define i1 @test9(i32 %d) { + %div = udiv i32 4, %d + %cmp1 = icmp ugt i32 %div, 2 + ret i1 %cmp1 +} + +; CHECK-LABEL: @test10 +; CHECK: %cmp1 = icmp ult i32 %d, 3 +define i1 @test10(i32 %d) { + %div = udiv i32 4, %d + %cmp1 = icmp ugt i32 %div, 1 + ret i1 %cmp1 +} + +; CHECK-LABEL: @test11 +; CHECK: %cmp1 = icmp ugt i32 %d, 4 +define i1 @test11(i32 %d) { + %div = udiv i32 4, %d + %cmp1 = icmp ult i32 %div, 1 + ret i1 %cmp1 +} + +; CHECK-LABEL: @test12 +; CHECK: %cmp1 = icmp ugt i32 %d, 2 +define i1 @test12(i32 %d) { + %div = udiv i32 4, %d + %cmp1 = icmp ult i32 %div, 2 + ret i1 %cmp1 +} + +; CHECK-LABEL: @test13 +; CHECK: %cmp1 = icmp ugt i32 %d, 1 +define i1 @test13(i32 %d) { + %div = udiv i32 4, %d + %cmp1 = icmp ult i32 %div, 3 + ret i1 %cmp1 +} + +; CHECK-LABEL: @test14 +; CHECK: %cmp1 = icmp ugt i32 %d, 1 +define i1 @test14(i32 %d) { + %div = udiv i32 4, %d + %cmp1 = icmp ult i32 %div, 4 + ret i1 %cmp1 +} + +; icmp ugt X, UINT_MAX -> false. +; CHECK-LABEL: @test15 +; CHECK: ret i1 false +define i1 @test15(i32 %d) { + %div = udiv i32 4, %d + %cmp1 = icmp ugt i32 %div, -1 + ret i1 %cmp1 +} + +; icmp ult X, UINT_MAX -> true. +; CHECK-LABEL: @test16 +; CHECK: ret i1 true +define i1 @test16(i32 %d) { + %div = udiv i32 4, %d + %cmp1 = icmp ult i32 %div, -1 + ret i1 %cmp1 +} |
