diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp index 7a184a19d7c54..a2769c96b2ef4 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -1326,6 +1326,18 @@ Instruction *InstCombinerImpl::foldAddLikeCommutative(Value *LHS, Value *RHS, R->setHasNoUnsignedWrap(NUWOut); return R; } + + // ((X s/ C1) << C2) + X => X s% -C1 where -C1 is 1 << C2 + const APInt *C1, *C2; + if (match(LHS, m_Shl(m_SDiv(m_Specific(RHS), m_APInt(C1)), m_APInt(C2)))) { + APInt One(C2->getBitWidth(), 1); + APInt MinusC1 = -(*C1); + if (MinusC1 == (One << *C2)) { + Constant *NewRHS = ConstantInt::get(RHS->getType(), MinusC1); + return BinaryOperator::CreateSRem(RHS, NewRHS); + } + } + return nullptr; } @@ -1623,17 +1635,7 @@ Instruction *InstCombinerImpl::visitAdd(BinaryOperator &I) { // X % C0 + (( X / C0 ) % C1) * C0 => X % (C0 * C1) if (Value *V = SimplifyAddWithRemainder(I)) return replaceInstUsesWith(I, V); - // ((X s/ C1) << C2) + X => X s% -C1 where -C1 is 1 << C2 - const APInt *C1, *C2; - if (match(LHS, m_Shl(m_SDiv(m_Specific(RHS), m_APInt(C1)), m_APInt(C2)))) { - APInt one(C2->getBitWidth(), 1); - APInt minusC1 = -(*C1); - if (minusC1 == (one << *C2)) { - Constant *NewRHS = ConstantInt::get(RHS->getType(), minusC1); - return BinaryOperator::CreateSRem(RHS, NewRHS); - } - } - + const APInt *C1; // (A & 2^C1) + A => A & (2^C1 - 1) iff bit C1 in A is a sign bit if (match(&I, m_c_Add(m_And(m_Value(A), m_APInt(C1)), m_Deferred(A))) && C1->isPowerOf2() && (ComputeNumSignBits(A) > C1->countl_zero())) { diff --git a/llvm/test/Transforms/InstCombine/add-shl-sdiv-to-srem.ll b/llvm/test/Transforms/InstCombine/add-shl-sdiv-to-srem.ll index 84462f9a7f592..d4edf12eba6ac 100644 --- a/llvm/test/Transforms/InstCombine/add-shl-sdiv-to-srem.ll +++ b/llvm/test/Transforms/InstCombine/add-shl-sdiv-to-srem.ll @@ -12,6 +12,17 @@ define i8 @add-shl-sdiv-scalar0(i8 %x) { ret i8 %rz } +define i8 @add-shl-sdiv-scalar0_commuted(i8 %x) { +; CHECK-LABEL: @add-shl-sdiv-scalar0_commuted( +; CHECK-NEXT: [[RZ:%.*]] = srem i8 [[X:%.*]], 4 +; CHECK-NEXT: ret i8 [[RZ]] +; + %sd = sdiv i8 %x, -4 + %sl = shl i8 %sd, 2 + %rz = add i8 %x, %sl + ret i8 %rz +} + define i8 @add-shl-sdiv-scalar1(i8 %x) { ; CHECK-LABEL: @add-shl-sdiv-scalar1( ; CHECK-NEXT: [[RZ:%.*]] = srem i8 [[X:%.*]], 64