[PATCH] D113783: [InstCombine] Fold (A^B)|~A-->~(A&B)

[Mehrnoosh Heidarpour via Phabricator via llvm-commits]

MehrHeidar updated this revision to Diff 386888.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D113783/new/

https://reviews.llvm.org/D113783

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  llvm/test/Transforms/InstCombine/and-or-icmps.ll
  llvm/test/Transforms/InstCombine/or-xor.ll


Index: llvm/test/Transforms/InstCombine/or-xor.ll
===================================================================
--- llvm/test/Transforms/InstCombine/or-xor.ll
+++ llvm/test/Transforms/InstCombine/or-xor.ll
@@ -59,6 +59,20 @@
   ret i32 %z
 }
 
+; ~X | (X ^ Y) --> ~(X & Y)
+
+define i32 @test5(i32 %x, i32 %y) {
+; CHECK-LABEL: @test5(
+; CHECK-NEXT:    [[TMP1:%.*]] = and i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[Z:%.*]] = xor i32 [[TMP1]], -1
+; CHECK-NEXT:    ret i32 [[Z]]
+;
+  %xor = xor i32 %x, %y
+  %notx = xor i32 %x, -1
+  %z = or i32 %xor, %notx
+  ret i32 %z
+}
+
 define i32 @test7(i32 %x, i32 %y) {
 ; CHECK-LABEL: @test7(
 ; CHECK-NEXT:    [[Z:%.*]] = or i32 [[X:%.*]], [[Y:%.*]]
Index: llvm/test/Transforms/InstCombine/and-or-icmps.ll
===================================================================
--- llvm/test/Transforms/InstCombine/and-or-icmps.ll
+++ llvm/test/Transforms/InstCombine/and-or-icmps.ll
@@ -369,12 +369,11 @@
 ; CHECK-NEXT:    [[B11:%.*]] = zext i1 [[TMP1]] to i16
 ; CHECK-NEXT:    [[C10:%.*]] = icmp ugt i16 [[L7]], [[B11]]
 ; CHECK-NEXT:    [[C5:%.*]] = icmp slt i16 [[L7]], 1
-; CHECK-NEXT:    [[C11:%.*]] = icmp ne i16 [[L7]], 0
 ; CHECK-NEXT:    [[C7:%.*]] = icmp slt i16 [[L7]], 0
 ; CHECK-NEXT:    [[B15:%.*]] = xor i1 [[C7]], [[C10]]
-; CHECK-NEXT:    [[B19:%.*]] = xor i1 [[C11]], [[B15]]
+; CHECK-NEXT:    [[C6:%.*]] = xor i1 [[B15]], true
 ; CHECK-NEXT:    [[TMP2:%.*]] = and i1 [[C10]], [[C5]]
-; CHECK-NEXT:    [[C3:%.*]] = and i1 [[TMP2]], [[B19]]
+; CHECK-NEXT:    [[C3:%.*]] = and i1 [[TMP2]], [[C6]]
 ; CHECK-NEXT:    [[TMP3:%.*]] = xor i1 [[C10]], true
 ; CHECK-NEXT:    [[C18:%.*]] = or i1 [[C7]], [[TMP3]]
 ; CHECK-NEXT:    [[TMP4:%.*]] = sext i1 [[C3]] to i64
Index: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2673,6 +2673,7 @@
 
   // A | ( A ^ B) -> A |  B
   // A | (~A ^ B) -> A | ~B
+  // ~A | (A ^ B) -> ~(A & B)
   // (A & B) | (A ^ B)
   if (match(Op1, m_Xor(m_Value(A), m_Value(B)))) {
     if (Op0 == A || Op0 == B)
@@ -2682,6 +2683,10 @@
         match(Op0, m_And(m_Specific(B), m_Specific(A))))
       return BinaryOperator::CreateOr(A, B);
 
+    if (Op1->hasOneUse() &&
+        (match(Op0, m_Not(m_Specific(A))) || match(Op0, m_Not(m_Specific(B)))))
+      return BinaryOperator::CreateNot(Builder.CreateAnd(A, B));
+
     if (Op1->hasOneUse() && match(A, m_Not(m_Specific(Op0)))) {
       Value *Not = Builder.CreateNot(B, B->getName() + ".not");
       return BinaryOperator::CreateOr(Not, Op0);


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