Relax equality no wrap constraints & remove swap handling

Author: Acthinks

llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

@@ -7751,17 +7751,10 @@ Instruction *InstCombinerImpl::visitICmpInst(ICmpInst &I) {
       bool I1NUW = I1->hasNoUnsignedWrap();
       bool I0NSW = I0->hasNoSignedWrap();
       bool I1NSW = I1->hasNoSignedWrap();
-      bool Swaped = false;
       if ((UnsignedCmp && I0NUW && I1NUW) || (SignedCmp && I0NSW && I1NSW) ||
-          (EqualityCmp && I0NUW && I0NSW && I1NUW && I1NSW)) {
-        if (I0->getOpcode() == Instruction::Add &&
-            I1->getOpcode() == Instruction::Sub) {
-          std::swap(I0, I1);
-          Swaped = true;
-        }
+          (EqualityCmp && ((I0NUW && I1NUW) || (I0NSW && I1NSW)))) {
         if (match(I0, m_Sub(m_Value(A), m_Value(B))) &&
-            (match(I1, m_Add(m_Specific(A), m_Specific(B))) ||
-             match(I1, m_Add(m_Specific(B), m_Specific(A))))) {
+            match(I1, m_Add(m_Specific(A), m_Specific(B)))) {
           return new ICmpInst(Swaped ? Pred : I.getSwappedPredicate(), B,
                               ConstantInt::get(Op0->getType(), 0));
         }

llvm/test/Transforms/InstCombine/icmp-subadd.ll

@@ -53,9 +53,7 @@ define i1 @test-same-operands-sub-add-nsw-nuw-icmp-eq(i8 %a, i8 %b) {
 define i1 @test-same-operands-sub-add-nsw-icmp-eq(i8 %a, i8 %b) {
 ; CHECK-LABEL: define i1 @test-same-operands-sub-add-nsw-icmp-eq(
 ; CHECK-SAME: i8 [[A:%.*]], i8 [[B:%.*]]) {
-; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i8 [[A]], [[B]]
-; CHECK-NEXT:    [[ADD:%.*]] = add nsw i8 [[A]], [[B]]
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8 [[SUB]], [[ADD]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8 [[B]], 0
 ; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %sub = sub nsw i8 %a, %b
@@ -64,10 +62,13 @@ define i1 @test-same-operands-sub-add-nsw-icmp-eq(i8 %a, i8 %b) {
   ret i1 %cmp
 }
 
+; Should floded by foldICmpCommutative in the future
 define i1 @test-add-sub-nsw-icmp-sgt(i8 %a, i8 %b) {
 ; CHECK-LABEL: define i1 @test-add-sub-nsw-icmp-sgt(
 ; CHECK-SAME: i8 [[A:%.*]], i8 [[B:%.*]]) {
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 [[B]], 0
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i8 [[A]], [[B]]
+; CHECK-NEXT:    [[ADD:%.*]] = add nsw i8 [[A]], [[B]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 [[ADD]], [[SUB]]
 ; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %sub = sub nsw i8 %a, %b
@@ -76,10 +77,14 @@ define i1 @test-add-sub-nsw-icmp-sgt(i8 %a, i8 %b) {
   ret i1 %cmp
 }
 
+; Should floded by foldICmpCommutative in the future
 define i1 @test-add-sub-nuw-icmp-uge(i8 %a, i8 %b) {
 ; CHECK-LABEL: define i1 @test-add-sub-nuw-icmp-uge(
 ; CHECK-SAME: i8 [[A:%.*]], i8 [[B:%.*]]) {
-; CHECK-NEXT:    ret i1 true
+; CHECK-NEXT:    [[SUB:%.*]] = sub nuw i8 [[A]], [[B]]
+; CHECK-NEXT:    [[ADD:%.*]] = add nuw i8 [[A]], [[B]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp uge i8 [[ADD]], [[SUB]]
+; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %sub = sub nuw i8 %a, %b
   %add = add nuw i8 %a, %b
@@ -102,10 +107,14 @@ define i1 @test-add-sub-nuw-icmp-sge(i8 %a, i8 %b) {
   ret i1 %cmp
 }
 
+; Should floded by foldICmpCommutative in the future
 define i1 @test-add-swap-sub-nuw-icmp-uge(i8 %a, i8 %b) {
 ; CHECK-LABEL: define i1 @test-add-swap-sub-nuw-icmp-uge(
 ; CHECK-SAME: i8 [[A:%.*]], i8 [[B:%.*]]) {
-; CHECK-NEXT:    ret i1 true
+; CHECK-NEXT:    [[SUB:%.*]] = sub nuw i8 [[A]], [[B]]
+; CHECK-NEXT:    [[ADD:%.*]] = add nuw i8 [[B]], [[A]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp uge i8 [[ADD]], [[SUB]]
+; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %sub = sub nuw i8 %a, %b
   %add = add nuw i8 %b, %a