diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp index bacb8689892a9..4ced5994ffa60 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -1801,6 +1801,12 @@ Instruction *InstCombinerImpl::visitSub(BinaryOperator &I) { return BinaryOperator::CreateSub(XZ, YW); } + // ((X - Y) - Op1) --> X - (Y + Op1) + if (match(Op0, m_OneUse(m_Sub(m_Value(X), m_Value(Y))))) { + Value *Add = Builder.CreateAdd(Y, Op1); + return BinaryOperator::CreateSub(X, Add); + } + auto m_AddRdx = [](Value *&Vec) { return m_OneUse(m_Intrinsic(m_Value(Vec))); }; diff --git a/llvm/test/Transforms/InstCombine/abs-1.ll b/llvm/test/Transforms/InstCombine/abs-1.ll index 7452798ead77a..ea77dfb5fef4d 100644 --- a/llvm/test/Transforms/InstCombine/abs-1.ll +++ b/llvm/test/Transforms/InstCombine/abs-1.ll @@ -305,9 +305,9 @@ define i32 @nabs_canonical_8(i32 %a) { define i32 @nabs_canonical_9(i32 %a, i32 %b) { ; CHECK-LABEL: @nabs_canonical_9( ; CHECK-NEXT: [[T1:%.*]] = sub i32 [[A:%.*]], [[B:%.*]] -; CHECK-NEXT: [[T2:%.*]] = sub i32 [[B]], [[A]] ; CHECK-NEXT: [[TMP1:%.*]] = call i32 @llvm.abs.i32(i32 [[T1]], i1 false) -; CHECK-NEXT: [[ADD:%.*]] = sub i32 [[T2]], [[TMP1]] +; CHECK-NEXT: [[TMP2:%.*]] = add i32 [[TMP1]], [[A]] +; CHECK-NEXT: [[ADD:%.*]] = sub i32 [[B]], [[TMP2]] ; CHECK-NEXT: ret i32 [[ADD]] ; %t1 = sub i32 %a, %b diff --git a/llvm/test/Transforms/InstCombine/sub-from-sub.ll b/llvm/test/Transforms/InstCombine/sub-from-sub.ll index 202dbd1072a4d..aaa8b1db32de6 100644 --- a/llvm/test/Transforms/InstCombine/sub-from-sub.ll +++ b/llvm/test/Transforms/InstCombine/sub-from-sub.ll @@ -8,8 +8,8 @@ declare void @use8(i8) ; Basic test define i8 @t0(i8 %x, i8 %y, i8 %z) { ; CHECK-LABEL: @t0( -; CHECK-NEXT: [[I0:%.*]] = sub i8 [[X:%.*]], [[Y:%.*]] -; CHECK-NEXT: [[R:%.*]] = sub i8 [[I0]], [[Z:%.*]] +; CHECK-NEXT: [[TMP1:%.*]] = add i8 [[Y:%.*]], [[Z:%.*]] +; CHECK-NEXT: [[R:%.*]] = sub i8 [[X:%.*]], [[TMP1]] ; CHECK-NEXT: ret i8 [[R]] ; %i0 = sub i8 %x, %y @@ -20,8 +20,8 @@ define i8 @t0(i8 %x, i8 %y, i8 %z) { ; No flags are propagated define i8 @t1_flags(i8 %x, i8 %y, i8 %z) { ; CHECK-LABEL: @t1_flags( -; CHECK-NEXT: [[O0:%.*]] = sub nuw nsw i8 [[X:%.*]], [[Y:%.*]] -; CHECK-NEXT: [[R:%.*]] = sub nuw nsw i8 [[O0]], [[Z:%.*]] +; CHECK-NEXT: [[TMP1:%.*]] = add i8 [[Y:%.*]], [[Z:%.*]] +; CHECK-NEXT: [[R:%.*]] = sub i8 [[X:%.*]], [[TMP1]] ; CHECK-NEXT: ret i8 [[R]] ; %o0 = sub nuw nsw i8 %x, %y @@ -47,8 +47,8 @@ define i8 @n2(i8 %x, i8 %y, i8 %z) { define i8 @t3_c0(i8 %y, i8 %z) { ; CHECK-LABEL: @t3_c0( -; CHECK-NEXT: [[I0:%.*]] = sub i8 42, [[Y:%.*]] -; CHECK-NEXT: [[R:%.*]] = sub i8 [[I0]], [[Z:%.*]] +; CHECK-NEXT: [[TMP1:%.*]] = add i8 [[Y:%.*]], [[Z:%.*]] +; CHECK-NEXT: [[R:%.*]] = sub i8 42, [[TMP1]] ; CHECK-NEXT: ret i8 [[R]] ; %i0 = sub i8 42, %y