[PATCH] D86395: [InstCombine] transform pattern "(~A & B) ^ A -> (A | B)" added

[Sanjay Patel via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG53e92b4c0efc: [InstCombine] (~A & B) ^ A -> A | B (authored by spatel).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D86395/new/

https://reviews.llvm.org/D86395

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  llvm/test/Transforms/InstCombine/xor.ll


Index: llvm/test/Transforms/InstCombine/xor.ll
===================================================================
--- llvm/test/Transforms/InstCombine/xor.ll
+++ llvm/test/Transforms/InstCombine/xor.ll
@@ -1176,9 +1176,7 @@
 
 define <2 x i32> @xor_andn_commute1(<2 x i32> %a, <2 x i32> %b) {
 ; CHECK-LABEL: @xor_andn_commute1(
-; CHECK-NEXT:    [[NOTA:%.*]] = xor <2 x i32> [[A:%.*]], <i32 -1, i32 -1>
-; CHECK-NEXT:    [[R:%.*]] = and <2 x i32> [[NOTA]], [[B:%.*]]
-; CHECK-NEXT:    [[Z:%.*]] = xor <2 x i32> [[R]], [[A]]
+; CHECK-NEXT:    [[Z:%.*]] = or <2 x i32> [[A:%.*]], [[B:%.*]]
 ; CHECK-NEXT:    ret <2 x i32> [[Z]]
 ;
   %nota = xor <2 x i32> %a, <i32 -1, i32 -1>
@@ -1192,9 +1190,7 @@
 define i33 @xor_andn_commute2(i33 %a, i33 %pb) {
 ; CHECK-LABEL: @xor_andn_commute2(
 ; CHECK-NEXT:    [[B:%.*]] = udiv i33 42, [[PB:%.*]]
-; CHECK-NEXT:    [[NOTA:%.*]] = xor i33 [[A:%.*]], -1
-; CHECK-NEXT:    [[R:%.*]] = and i33 [[B]], [[NOTA]]
-; CHECK-NEXT:    [[Z:%.*]] = xor i33 [[R]], [[A]]
+; CHECK-NEXT:    [[Z:%.*]] = or i33 [[B]], [[A:%.*]]
 ; CHECK-NEXT:    ret i33 [[Z]]
 ;
   %b = udiv i33 42, %pb ; thwart complexity-based canonicalization
@@ -1209,9 +1205,7 @@
 define i32 @xor_andn_commute3(i32 %pa, i32 %b) {
 ; CHECK-LABEL: @xor_andn_commute3(
 ; CHECK-NEXT:    [[A:%.*]] = udiv i32 42, [[PA:%.*]]
-; CHECK-NEXT:    [[NOTA:%.*]] = xor i32 [[A]], -1
-; CHECK-NEXT:    [[R:%.*]] = and i32 [[NOTA]], [[B:%.*]]
-; CHECK-NEXT:    [[Z:%.*]] = xor i32 [[A]], [[R]]
+; CHECK-NEXT:    [[Z:%.*]] = or i32 [[A]], [[B:%.*]]
 ; CHECK-NEXT:    ret i32 [[Z]]
 ;
   %a = udiv i32 42, %pa ; thwart complexity-based canonicalization
@@ -1227,9 +1221,7 @@
 ; CHECK-LABEL: @xor_andn_commute4(
 ; CHECK-NEXT:    [[A:%.*]] = udiv i32 42, [[PA:%.*]]
 ; CHECK-NEXT:    [[B:%.*]] = udiv i32 42, [[PB:%.*]]
-; CHECK-NEXT:    [[NOTA:%.*]] = xor i32 [[A]], -1
-; CHECK-NEXT:    [[R:%.*]] = and i32 [[B]], [[NOTA]]
-; CHECK-NEXT:    [[Z:%.*]] = xor i32 [[A]], [[R]]
+; CHECK-NEXT:    [[Z:%.*]] = or i32 [[A]], [[B]]
 ; CHECK-NEXT:    ret i32 [[Z]]
 ;
   %a = udiv i32 42, %pa ; thwart complexity-based canonicalization
Index: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -3335,6 +3335,10 @@
       match(Op1, m_Not(m_Specific(A))))
     return BinaryOperator::CreateNot(Builder.CreateAnd(A, B));
 
+  // (~A & B) ^ A --> A | B -- There are 4 commuted variants.
+  if (match(&I, m_c_Xor(m_c_And(m_Not(m_Value(A)), m_Value(B)), m_Deferred(A))))
+    return BinaryOperator::CreateOr(A, B);
+
   // (A | B) ^ (A | C) --> (B ^ C) & ~A -- There are 4 commuted variants.
   // TODO: Loosen one-use restriction if common operand is a constant.
   Value *D;


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