/// @brief Common integer divide transforms
Instruction *InstCombiner::commonIDivTransforms(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ bool IsSigned = I.getOpcode() == Instruction::SDiv;
// The RHS is known non-zero.
if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this, I)) {
if (match(Op1, m_APInt(C2))) {
Value *X;
const APInt *C1;
- bool IsSigned = I.getOpcode() == Instruction::SDiv;
// (X / C1) / C2 -> X / (C1*C2)
if ((IsSigned && match(LHS, m_SDiv(m_Value(X), m_APInt(C1)))) ||
return &I;
// (X - (X rem Y)) / Y -> X / Y; usually originates as ((X / Y) * Y) / Y
- Value *X = nullptr, *Z = nullptr;
- if (match(Op0, m_Sub(m_Value(X), m_Value(Z)))) { // (X - Z) / Y; Y = Op1
- bool isSigned = I.getOpcode() == Instruction::SDiv;
- if ((isSigned && match(Z, m_SRem(m_Specific(X), m_Specific(Op1)))) ||
- (!isSigned && match(Z, m_URem(m_Specific(X), m_Specific(Op1)))))
+ Value *X, *Z;
+ if (match(Op0, m_Sub(m_Value(X), m_Value(Z)))) // (X - Z) / Y; Y = Op1
+ if ((IsSigned && match(Z, m_SRem(m_Specific(X), m_Specific(Op1)))) ||
+ (!IsSigned && match(Z, m_URem(m_Specific(X), m_Specific(Op1)))))
return BinaryOperator::Create(I.getOpcode(), X, Op1);
- }
+
+ // (X << Y) / X -> 1 << Y
+ Value *Y;
+ if (IsSigned && match(Op0, m_NSWShl(m_Specific(Op1), m_Value(Y))))
+ return BinaryOperator::CreateNSWShl(ConstantInt::get(I.getType(), 1), Y);
+ if (!IsSigned && match(Op0, m_NUWShl(m_Specific(Op1), m_Value(Y))))
+ return BinaryOperator::CreateNUWShl(ConstantInt::get(I.getType(), 1), Y);
return nullptr;
}
define i32 @t7(i32 %x) {
; CHECK-LABEL: @t7(
-; CHECK-NEXT: [[SHL:%.*]] = shl nsw i32 [[X:%.*]], 2
-; CHECK-NEXT: [[R:%.*]] = sdiv i32 [[SHL]], [[X]]
-; CHECK-NEXT: ret i32 [[R]]
+; CHECK-NEXT: ret i32 4
;
%shl = shl nsw i32 %x, 2
%r = sdiv i32 %shl, %x
define <2 x i32> @t9(<2 x i32> %x) {
; CHECK-LABEL: @t9(
-; CHECK-NEXT: [[SHL:%.*]] = shl nsw <2 x i32> [[X:%.*]], <i32 2, i32 3>
-; CHECK-NEXT: [[R:%.*]] = sdiv <2 x i32> [[SHL]], [[X]]
-; CHECK-NEXT: ret <2 x i32> [[R]]
+; CHECK-NEXT: ret <2 x i32> <i32 4, i32 8>
;
%shl = shl nsw <2 x i32> %x, <i32 2, i32 3>
%r = sdiv <2 x i32> %shl, %x
define i32 @t10(i32 %x, i32 %y) {
; CHECK-LABEL: @t10(
-; CHECK-NEXT: [[SHL:%.*]] = shl nsw i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: [[R:%.*]] = sdiv i32 [[SHL]], [[X]]
+; CHECK-NEXT: [[R:%.*]] = shl nsw i32 1, [[Y:%.*]]
; CHECK-NEXT: ret i32 [[R]]
;
%shl = shl nsw i32 %x, %y
define <2 x i32> @t11(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @t11(
-; CHECK-NEXT: [[SHL:%.*]] = shl nsw <2 x i32> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: [[R:%.*]] = sdiv <2 x i32> [[SHL]], [[X]]
+; CHECK-NEXT: [[R:%.*]] = shl nsw <2 x i32> <i32 1, i32 1>, [[Y:%.*]]
; CHECK-NEXT: ret <2 x i32> [[R]]
;
%shl = shl nsw <2 x i32> %x, %y
define i32 @t12(i32 %x) {
; CHECK-LABEL: @t12(
-; CHECK-NEXT: [[SHL:%.*]] = shl nuw i32 [[X:%.*]], 2
-; CHECK-NEXT: [[R:%.*]] = udiv i32 [[SHL]], [[X]]
-; CHECK-NEXT: ret i32 [[R]]
+; CHECK-NEXT: ret i32 4
;
%shl = shl nuw i32 %x, 2
%r = udiv i32 %shl, %x
define <2 x i32> @t14(<2 x i32> %x) {
; CHECK-LABEL: @t14(
-; CHECK-NEXT: [[SHL:%.*]] = shl nuw <2 x i32> [[X:%.*]], <i32 2, i32 3>
-; CHECK-NEXT: [[R:%.*]] = udiv <2 x i32> [[SHL]], [[X]]
-; CHECK-NEXT: ret <2 x i32> [[R]]
+; CHECK-NEXT: ret <2 x i32> <i32 4, i32 8>
;
%shl = shl nuw <2 x i32> %x, <i32 2, i32 3>
%r = udiv <2 x i32> %shl, %x
define i32 @t15(i32 %x, i32 %y) {
; CHECK-LABEL: @t15(
-; CHECK-NEXT: [[SHL:%.*]] = shl nuw i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: [[R:%.*]] = udiv i32 [[SHL]], [[X]]
+; CHECK-NEXT: [[R:%.*]] = shl nuw i32 1, [[Y:%.*]]
; CHECK-NEXT: ret i32 [[R]]
;
%shl = shl nuw i32 %x, %y
define <2 x i32> @t16(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @t16(
-; CHECK-NEXT: [[SHL:%.*]] = shl nuw <2 x i32> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: [[R:%.*]] = udiv <2 x i32> [[SHL]], [[X]]
+; CHECK-NEXT: [[R:%.*]] = shl nuw <2 x i32> <i32 1, i32 1>, [[Y:%.*]]
; CHECK-NEXT: ret <2 x i32> [[R]]
;
%shl = shl nuw <2 x i32> %x, %y