Revert "[InstCombine] [InstCombine] Canonicalize (-X s/ Y) to -(X s/ Y)."

This reverts commit 1383a9168948aabfd827220c9445ce0ce5765800.

sdiv-canonicalize.ll fails after this revision. The fold needs to be
moved outside the branch handling constant operands. However when this
is done there are further test changes, so I'm reverting this in the
meantime.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358026 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 2db6e84..cb87084 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -1043,12 +1043,6 @@ Instruction *InstCombiner::visitSDiv(BinaryOperator &I) {
       Value *NarrowOp = Builder.CreateSDiv(Op0Src, NarrowDivisor);
       return new SExtInst(NarrowOp, Op0->getType());
     }
-  
-  // -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()));
 
     // -X / C --> X / -C (if the negation doesn't overflow).
     // TODO: This could be enhanced to handle arbitrary vector constants by

diff --git a/test/Transforms/InstCombine/sdiv-canonicalize.ll b/test/Transforms/InstCombine/sdiv-canonicalize.ll
index 39ba512..8e1497b 100644 (file)
--- a/test/Transforms/InstCombine/sdiv-canonicalize.ll
+++ b/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:    [[SDIV1:%.*]] = sdiv i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[SDIV:%.*]] = sub nsw i32 0, [[SDIV1]]
+; CHECK-NEXT:    [[NEG:%.*]] = sub nsw i32 0, [[X:%.*]]
+; CHECK-NEXT:    [[SDIV:%.*]] = sdiv i32 [[NEG]], [[Y:%.*]]
 ; 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:    [[SDIV1:%.*]] = sdiv exact i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[SDIV:%.*]] = sub nsw i32 0, [[SDIV1]]
+; CHECK-NEXT:    [[NEG:%.*]] = sub nsw i32 0, [[X:%.*]]
+; CHECK-NEXT:    [[SDIV:%.*]] = sdiv exact i32 [[NEG]], [[Y:%.*]]
 ; CHECK-NEXT:    ret i32 [[SDIV]]
 ;
   %neg = sub nsw i32 0, %x
@@ -23,7 +23,6 @@ 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
@@ -50,8 +49,8 @@ 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:    [[SDIV1:%.*]] = sdiv <2 x i32> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[SDIV:%.*]] = sub nsw <2 x i32> zeroinitializer, [[SDIV1]]
+; CHECK-NEXT:    [[NEG:%.*]] = sub nsw <2 x i32> zeroinitializer, [[X:%.*]]
+; CHECK-NEXT:    [[SDIV:%.*]] = sdiv <2 x i32> [[NEG]], [[Y:%.*]]
 ; CHECK-NEXT:    ret <2 x i32> [[SDIV]]
 ;
   %neg = sub nsw <2 x i32> <i32 0, i32 0>, %x
@@ -72,8 +71,9 @@ define i32 @test_sdiv_canonicalize_multiple_uses(i32 %x, i32 %y) {
   ret i32 %sdiv2
 }
 
-; There is combination: -(X/CE) -> (X/-CE).
-; If combines (X/-CE) to -(X/CE), make sure don't combine them endless.
+; There is combination: (X/-CE) -> -(X/CE)
+; There is another combination: -(X/CE) -> (X/-CE)
+; Make sure don't combine them endless.
 
 @X = global i32 5