diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp --- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -2639,6 +2639,15 @@ return BinaryOperator::CreateXor(Or, ConstantInt::get(Ty, *CV)); } + // If the operands have no common bits set: + // or (mul X, Y), X --> add (mul X, Y), X --> mul X, (Y + 1) + if (match(&I, + m_c_Or(m_OneUse(m_Mul(m_Value(X), m_Value(Y))), m_Deferred(X))) && + haveNoCommonBitsSet(Op0, Op1, DL)) { + Value *IncrementY = Builder.CreateAdd(Y, ConstantInt::get(Ty, 1)); + return BinaryOperator::CreateMul(X, IncrementY); + } + // (A & C) | (B & D) Value *A, *B, *C, *D; if (match(Op0, m_And(m_Value(A), m_Value(C))) && diff --git a/llvm/test/Transforms/InstCombine/or.ll b/llvm/test/Transforms/InstCombine/or.ll --- a/llvm/test/Transforms/InstCombine/or.ll +++ b/llvm/test/Transforms/InstCombine/or.ll @@ -1446,8 +1446,8 @@ ; CHECK-LABEL: @mul_no_common_bits( ; CHECK-NEXT: [[X:%.*]] = and i32 [[P1:%.*]], 7 ; CHECK-NEXT: [[Y:%.*]] = shl i32 [[P2:%.*]], 3 -; CHECK-NEXT: [[M:%.*]] = mul i32 [[X]], [[Y]] -; CHECK-NEXT: [[R:%.*]] = or i32 [[M]], [[X]] +; CHECK-NEXT: [[TMP1:%.*]] = or i32 [[Y]], 1 +; CHECK-NEXT: [[R:%.*]] = mul i32 [[X]], [[TMP1]] ; CHECK-NEXT: ret i32 [[R]] ; %x = and i32 %p1, 7 @@ -1460,8 +1460,7 @@ define i32 @mul_no_common_bits_const_op(i32 %p) { ; CHECK-LABEL: @mul_no_common_bits_const_op( ; CHECK-NEXT: [[X:%.*]] = and i32 [[P:%.*]], 7 -; CHECK-NEXT: [[M:%.*]] = mul nuw nsw i32 [[X]], 24 -; CHECK-NEXT: [[R:%.*]] = or i32 [[M]], [[X]] +; CHECK-NEXT: [[R:%.*]] = mul nuw nsw i32 [[X]], 25 ; CHECK-NEXT: ret i32 [[R]] ; %x = and i32 %p, 7 @@ -1473,8 +1472,7 @@ define <2 x i12> @mul_no_common_bits_commute(<2 x i12> %p) { ; CHECK-LABEL: @mul_no_common_bits_commute( ; CHECK-NEXT: [[X:%.*]] = and <2 x i12> [[P:%.*]], -; CHECK-NEXT: [[M:%.*]] = mul nuw nsw <2 x i12> [[X]], -; CHECK-NEXT: [[R:%.*]] = or <2 x i12> [[X]], [[M]] +; CHECK-NEXT: [[R:%.*]] = mul nuw nsw <2 x i12> [[X]], ; CHECK-NEXT: ret <2 x i12> [[R]] ; %x = and <2 x i12> %p, @@ -1483,8 +1481,29 @@ ret <2 x i12> %r } -define i32 @mul_no_common_bits_uses(i32 %p) { +; negative test - extra use requires extra instructions + +define i32 @mul_no_common_bits_uses(i32 %p1, i32 %p2) { ; CHECK-LABEL: @mul_no_common_bits_uses( +; CHECK-NEXT: [[X:%.*]] = and i32 [[P1:%.*]], 7 +; CHECK-NEXT: [[Y:%.*]] = shl i32 [[P2:%.*]], 3 +; CHECK-NEXT: [[M:%.*]] = mul i32 [[X]], [[Y]] +; CHECK-NEXT: call void @use(i32 [[M]]) +; CHECK-NEXT: [[R:%.*]] = or i32 [[M]], [[X]] +; CHECK-NEXT: ret i32 [[R]] +; + %x = and i32 %p1, 7 + %y = shl i32 %p2, 3 + %m = mul i32 %x, %y + call void @use(i32 %m) + %r = or i32 %m, %x + ret i32 %r +} + +; negative test - probably not good to create an extra mul + +define i32 @mul_no_common_bits_const_op_uses(i32 %p) { +; CHECK-LABEL: @mul_no_common_bits_const_op_uses( ; CHECK-NEXT: [[X:%.*]] = and i32 [[P:%.*]], 7 ; CHECK-NEXT: [[M:%.*]] = mul nuw nsw i32 [[X]], 24 ; CHECK-NEXT: call void @use(i32 [[M]]) @@ -1498,6 +1517,8 @@ ret i32 %r } +; negative test - %x and %m may have set 3rd bit + define i32 @mul_common_bits(i32 %p) { ; CHECK-LABEL: @mul_common_bits( ; CHECK-NEXT: [[X:%.*]] = and i32 [[P:%.*]], 7