diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 6 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/div.ll | 12 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/sdiv-canonicalize.ll | 18 |
3 files changed, 21 insertions, 15 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp index cb8708446b2..e53eac2dd4e 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp @@ -1056,6 +1056,12 @@ Instruction *InstCombiner::visitSDiv(BinaryOperator &I) { } } + // -X / Y --> -(X / Y) + Value *Y; + if (match(&I, m_SDiv(m_OneUse(m_NSWSub(m_Zero(), m_Value(X))), m_Value(Y)))) + return BinaryOperator::CreateNSWNeg( + Builder.CreateSDiv(X, Y, I.getName(), I.isExact())); + // If the sign bits of both operands are zero (i.e. we can prove they are // unsigned inputs), turn this into a udiv. APInt Mask(APInt::getSignMask(I.getType()->getScalarSizeInBits())); diff --git a/llvm/test/Transforms/InstCombine/div.ll b/llvm/test/Transforms/InstCombine/div.ll index 6b373328016..4c4308151e7 100644 --- a/llvm/test/Transforms/InstCombine/div.ll +++ b/llvm/test/Transforms/InstCombine/div.ll @@ -522,8 +522,8 @@ define <2 x i8> @sdiv_negated_dividend_constant_divisor_vec_undef(<2 x i8> %x) { define <2 x i64> @sdiv_negated_dividend_constant_divisor_vec(<2 x i64> %x) { ; CHECK-LABEL: @sdiv_negated_dividend_constant_divisor_vec( -; CHECK-NEXT: [[NEG:%.*]] = sub nsw <2 x i64> zeroinitializer, [[X:%.*]] -; CHECK-NEXT: [[DIV:%.*]] = sdiv <2 x i64> [[NEG]], <i64 3, i64 4> +; CHECK-NEXT: [[DIV1:%.*]] = sdiv <2 x i64> [[X:%.*]], <i64 3, i64 4> +; CHECK-NEXT: [[DIV:%.*]] = sub nsw <2 x i64> zeroinitializer, [[DIV1]] ; CHECK-NEXT: ret <2 x i64> [[DIV]] ; %neg = sub nsw <2 x i64> zeroinitializer, %x @@ -533,8 +533,8 @@ define <2 x i64> @sdiv_negated_dividend_constant_divisor_vec(<2 x i64> %x) { define <2 x i64> @sdiv_exact_negated_dividend_constant_divisor_vec(<2 x i64> %x) { ; CHECK-LABEL: @sdiv_exact_negated_dividend_constant_divisor_vec( -; CHECK-NEXT: [[NEG:%.*]] = sub nsw <2 x i64> zeroinitializer, [[X:%.*]] -; CHECK-NEXT: [[DIV:%.*]] = sdiv exact <2 x i64> [[NEG]], <i64 3, i64 4> +; CHECK-NEXT: [[DIV1:%.*]] = sdiv exact <2 x i64> [[X:%.*]], <i64 3, i64 4> +; CHECK-NEXT: [[DIV:%.*]] = sub nsw <2 x i64> zeroinitializer, [[DIV1]] ; CHECK-NEXT: ret <2 x i64> [[DIV]] ; %neg = sub nsw <2 x i64> zeroinitializer, %x @@ -546,8 +546,8 @@ define <2 x i64> @sdiv_exact_negated_dividend_constant_divisor_vec(<2 x i64> %x) define <2 x i8> @sdiv_exact_negated_dividend_constant_divisor_vec_overflow(<2 x i8> %x) { ; CHECK-LABEL: @sdiv_exact_negated_dividend_constant_divisor_vec_overflow( -; CHECK-NEXT: [[NEG:%.*]] = sub nsw <2 x i8> zeroinitializer, [[X:%.*]] -; CHECK-NEXT: [[DIV:%.*]] = sdiv exact <2 x i8> [[NEG]], <i8 -128, i8 42> +; CHECK-NEXT: [[DIV1:%.*]] = sdiv exact <2 x i8> [[X:%.*]], <i8 -128, i8 42> +; CHECK-NEXT: [[DIV:%.*]] = sub nsw <2 x i8> zeroinitializer, [[DIV1]] ; CHECK-NEXT: ret <2 x i8> [[DIV]] ; %neg = sub nsw <2 x i8> zeroinitializer, %x diff --git a/llvm/test/Transforms/InstCombine/sdiv-canonicalize.ll b/llvm/test/Transforms/InstCombine/sdiv-canonicalize.ll index 8e1497b900a..39ba5120ed6 100644 --- a/llvm/test/Transforms/InstCombine/sdiv-canonicalize.ll +++ b/llvm/test/Transforms/InstCombine/sdiv-canonicalize.ll @@ -3,8 +3,8 @@ define i32 @test_sdiv_canonicalize_op0(i32 %x, i32 %y) { ; CHECK-LABEL: @test_sdiv_canonicalize_op0( -; CHECK-NEXT: [[NEG:%.*]] = sub nsw i32 0, [[X:%.*]] -; CHECK-NEXT: [[SDIV:%.*]] = sdiv i32 [[NEG]], [[Y:%.*]] +; CHECK-NEXT: [[SDIV1:%.*]] = sdiv i32 [[X:%.*]], [[Y:%.*]] +; CHECK-NEXT: [[SDIV:%.*]] = sub nsw i32 0, [[SDIV1]] ; CHECK-NEXT: ret i32 [[SDIV]] ; %neg = sub nsw i32 0, %x @@ -14,8 +14,8 @@ define i32 @test_sdiv_canonicalize_op0(i32 %x, i32 %y) { define i32 @test_sdiv_canonicalize_op0_exact(i32 %x, i32 %y) { ; CHECK-LABEL: @test_sdiv_canonicalize_op0_exact( -; CHECK-NEXT: [[NEG:%.*]] = sub nsw i32 0, [[X:%.*]] -; CHECK-NEXT: [[SDIV:%.*]] = sdiv exact i32 [[NEG]], [[Y:%.*]] +; CHECK-NEXT: [[SDIV1:%.*]] = sdiv exact i32 [[X:%.*]], [[Y:%.*]] +; CHECK-NEXT: [[SDIV:%.*]] = sub nsw i32 0, [[SDIV1]] ; CHECK-NEXT: ret i32 [[SDIV]] ; %neg = sub nsw i32 0, %x @@ -23,6 +23,7 @@ define i32 @test_sdiv_canonicalize_op0_exact(i32 %x, i32 %y) { ret i32 %sdiv } +; (X/-Y) is not equal to -(X/Y), don't canonicalize. define i32 @test_sdiv_canonicalize_op1(i32 %x, i32 %z) { ; CHECK-LABEL: @test_sdiv_canonicalize_op1( ; CHECK-NEXT: [[Y:%.*]] = mul i32 [[Z:%.*]], 3 @@ -49,8 +50,8 @@ define i32 @test_sdiv_canonicalize_nonsw(i32 %x, i32 %y) { define <2 x i32> @test_sdiv_canonicalize_vec(<2 x i32> %x, <2 x i32> %y) { ; CHECK-LABEL: @test_sdiv_canonicalize_vec( -; CHECK-NEXT: [[NEG:%.*]] = sub nsw <2 x i32> zeroinitializer, [[X:%.*]] -; CHECK-NEXT: [[SDIV:%.*]] = sdiv <2 x i32> [[NEG]], [[Y:%.*]] +; CHECK-NEXT: [[SDIV1:%.*]] = sdiv <2 x i32> [[X:%.*]], [[Y:%.*]] +; CHECK-NEXT: [[SDIV:%.*]] = sub nsw <2 x i32> zeroinitializer, [[SDIV1]] ; CHECK-NEXT: ret <2 x i32> [[SDIV]] ; %neg = sub nsw <2 x i32> <i32 0, i32 0>, %x @@ -71,9 +72,8 @@ define i32 @test_sdiv_canonicalize_multiple_uses(i32 %x, i32 %y) { ret i32 %sdiv2 } -; There is combination: (X/-CE) -> -(X/CE) -; There is another combination: -(X/CE) -> (X/-CE) -; Make sure don't combine them endless. +; There is combination: -(X/CE) -> (X/-CE). +; If combines (X/-CE) to -(X/CE), make sure don't combine them endless. @X = global i32 5 |
