return nullptr;
}
+static Value *takeLog2(IRBuilderBase &Builder, Value *Op, unsigned Depth,
+ bool DoFold);
+
Instruction *InstCombinerImpl::visitMul(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
if (Value *V =
m_c_UMin(m_Deferred(X), m_Deferred(Y))))))
return BinaryOperator::CreateWithCopiedFlags(Instruction::Mul, X, Y, &I);
+ // (mul Op0 Op1):
+ // if Log2(Op0) folds away ->
+ // (shl Op1, Log2(Op0))
+ // if Log2(Op1) folds away ->
+ // (shl Op0, Log2(Op1))
+ if (takeLog2(Builder, Op0, /*Depth*/ 0, /*DoFold*/ false)) {
+ Value *Res = takeLog2(Builder, Op0, /*Depth*/ 0, /*DoFold*/ true);
+ BinaryOperator *Shl = BinaryOperator::CreateShl(Op1, Res);
+ // We can only propegate nuw flag.
+ Shl->setHasNoUnsignedWrap(HasNUW);
+ return Shl;
+ }
+ if (takeLog2(Builder, Op1, /*Depth*/ 0, /*DoFold*/ false)) {
+ Value *Res = takeLog2(Builder, Op1, /*Depth*/ 0, /*DoFold*/ true);
+ BinaryOperator *Shl = BinaryOperator::CreateShl(Op0, Res);
+ // We can only propegate nuw flag.
+ Shl->setHasNoUnsignedWrap(HasNUW);
+ return Shl;
+ }
+
bool Changed = false;
if (!HasNSW && willNotOverflowSignedMul(Op0, Op1, I)) {
Changed = true;
declare void @use_i8(i8)
define i8 @mul_selectp2_x(i8 %x, i1 %c) {
; CHECK-LABEL: @mul_selectp2_x(
-; CHECK-NEXT: [[S:%.*]] = select i1 [[C:%.*]], i8 2, i8 4
-; CHECK-NEXT: [[R:%.*]] = mul i8 [[S]], [[X:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i8 1, i8 2
+; CHECK-NEXT: [[R:%.*]] = shl i8 [[X:%.*]], [[TMP1]]
; CHECK-NEXT: ret i8 [[R]]
;
%s = select i1 %c, i8 2, i8 4
define i8 @mul_selectp2_x_propegate_nuw(i8 %x, i1 %c) {
; CHECK-LABEL: @mul_selectp2_x_propegate_nuw(
-; CHECK-NEXT: [[S:%.*]] = select i1 [[C:%.*]], i8 2, i8 4
-; CHECK-NEXT: [[R:%.*]] = mul nuw nsw i8 [[S]], [[X:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i8 1, i8 2
+; CHECK-NEXT: [[R:%.*]] = shl nuw i8 [[X:%.*]], [[TMP1]]
; CHECK-NEXT: ret i8 [[R]]
;
%s = select i1 %c, i8 2, i8 4
define i8 @mul_selectp2_x_multiuse_fixme(i8 %x, i1 %c) {
; CHECK-LABEL: @mul_selectp2_x_multiuse_fixme(
; CHECK-NEXT: [[S:%.*]] = select i1 [[C:%.*]], i8 2, i8 4
-; CHECK-NEXT: [[R:%.*]] = mul i8 [[S]], [[X:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C]], i8 1, i8 2
+; CHECK-NEXT: [[R:%.*]] = shl i8 [[X:%.*]], [[TMP1]]
; CHECK-NEXT: call void @use_i8(i8 [[S]])
; CHECK-NEXT: ret i8 [[R]]
;
define i8 @mul_selectp2_x_non_const(i8 %x, i1 %c, i8 %yy) {
; CHECK-LABEL: @mul_selectp2_x_non_const(
-; CHECK-NEXT: [[Y:%.*]] = shl nuw i8 1, [[YY:%.*]]
-; CHECK-NEXT: [[S:%.*]] = select i1 [[C:%.*]], i8 2, i8 [[Y]]
-; CHECK-NEXT: [[R:%.*]] = mul i8 [[S]], [[X:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i8 1, i8 [[YY:%.*]]
+; CHECK-NEXT: [[R:%.*]] = shl i8 [[X:%.*]], [[TMP1]]
; CHECK-NEXT: ret i8 [[R]]
;
%y = shl i8 1, %yy
define i8 @mul_selectp2_x_non_const_multiuse(i8 %x, i1 %c, i8 %yy) {
; CHECK-LABEL: @mul_selectp2_x_non_const_multiuse(
; CHECK-NEXT: [[Y:%.*]] = shl nuw i8 1, [[YY:%.*]]
-; CHECK-NEXT: [[S:%.*]] = select i1 [[C:%.*]], i8 2, i8 [[Y]]
-; CHECK-NEXT: [[R:%.*]] = mul i8 [[S]], [[X:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i8 1, i8 [[YY]]
+; CHECK-NEXT: [[R:%.*]] = shl i8 [[X:%.*]], [[TMP1]]
; CHECK-NEXT: call void @use_i8(i8 [[Y]])
; CHECK-NEXT: ret i8 [[R]]
;
define i8 @mul_x_selectp2(i8 %xx, i1 %c) {
; CHECK-LABEL: @mul_x_selectp2(
; CHECK-NEXT: [[X:%.*]] = mul i8 [[XX:%.*]], [[XX]]
-; CHECK-NEXT: [[S:%.*]] = select i1 [[C:%.*]], i8 8, i8 1
-; CHECK-NEXT: [[R:%.*]] = mul i8 [[X]], [[S]]
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i8 3, i8 0
+; CHECK-NEXT: [[R:%.*]] = shl i8 [[X]], [[TMP1]]
; CHECK-NEXT: ret i8 [[R]]
;
%x = mul i8 %xx, %xx
define <2 x i8> @mul_x_selectp2_vec(<2 x i8> %xx, i1 %c) {
; CHECK-LABEL: @mul_x_selectp2_vec(
; CHECK-NEXT: [[X:%.*]] = mul <2 x i8> [[XX:%.*]], [[XX]]
-; CHECK-NEXT: [[S:%.*]] = select i1 [[C:%.*]], <2 x i8> <i8 8, i8 16>, <2 x i8> <i8 4, i8 1>
-; CHECK-NEXT: [[R:%.*]] = mul <2 x i8> [[X]], [[S]]
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], <2 x i8> <i8 3, i8 4>, <2 x i8> <i8 2, i8 0>
+; CHECK-NEXT: [[R:%.*]] = shl <2 x i8> [[X]], [[TMP1]]
; CHECK-NEXT: ret <2 x i8> [[R]]
;
%x = mul <2 x i8> %xx, %xx