[llvm] r306027 - [InstCombine] Add one use checks to or/and->xnor folding

[Craig Topper via llvm-commits]

Author: ctopper
Date: Thu Jun 22 11:12:02 2017
New Revision: 306027

URL: http://llvm.org/viewvc/llvm-project?rev=306027&view=rev
Log:
[InstCombine] Add one use checks to or/and->xnor folding

If the components of the and/or had multiple uses, this transform created an additional instruction.

This patch makes sure we remove one of the components.

Differential Revision: https://reviews.llvm.org/D34498

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
    llvm/trunk/test/Transforms/InstCombine/and-or-not.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp?rev=306027&r1=306026&r2=306027&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp Thu Jun 22 11:12:02 2017
@@ -1230,9 +1230,10 @@ static Instruction *foldAndToXor(BinaryO
   // (A | ~B) & (B | ~A) --> ~(A ^ B)
   // (~B | A) & (~A | B) --> ~(A ^ B)
   // (~B | A) & (B | ~A) --> ~(A ^ B)
-  if (match(Op0, m_c_Or(m_Value(A), m_Not(m_Value(B)))) &&
-      match(Op1, m_c_Or(m_Not(m_Specific(A)), m_Specific(B))))
-    return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
+  if (Op0->hasOneUse() || Op1->hasOneUse())
+    if (match(Op0, m_c_Or(m_Value(A), m_Not(m_Value(B)))) &&
+        match(Op1, m_c_Or(m_Not(m_Specific(A)), m_Specific(B))))
+      return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
 
   return nullptr;
 }
@@ -1247,9 +1248,10 @@ static Instruction *foldOrToXor(BinaryOp
   // Operand complexity canonicalization guarantees that the 'and' is Op0.
   // (A & B) | ~(A | B) --> ~(A ^ B)
   // (A & B) | ~(B | A) --> ~(A ^ B)
-  if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
-      match(Op1, m_Not(m_c_Or(m_Specific(A), m_Specific(B)))))
-    return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
+  if (Op0->hasOneUse() || Op1->hasOneUse())
+    if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
+        match(Op1, m_Not(m_c_Or(m_Specific(A), m_Specific(B)))))
+      return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
 
   // (A & ~B) | (~A & B) --> A ^ B
   // (A & ~B) | (B & ~A) --> A ^ B

Modified: llvm/trunk/test/Transforms/InstCombine/and-or-not.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/and-or-not.ll?rev=306027&r1=306026&r2=306027&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/and-or-not.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/and-or-not.ll Thu Jun 22 11:12:02 2017
@@ -527,8 +527,7 @@ define i32 @and_to_nxor_multiuse(float %
 ; CHECK-NEXT:    [[NOTB:%.*]] = xor i32 [[B]], -1
 ; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[NOTA]], [[B]]
 ; CHECK-NEXT:    [[OR2:%.*]] = or i32 [[NOTB]], [[A]]
-; CHECK-NEXT:    [[TMP1:%.*]] = xor i32 [[B]], [[A]]
-; CHECK-NEXT:    [[AND:%.*]] = xor i32 [[TMP1]], -1
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[OR1]], [[OR2]]
 ; CHECK-NEXT:    [[MUL1:%.*]] = mul i32 [[OR1]], [[OR2]]
 ; CHECK-NEXT:    [[MUL2:%.*]] = mul i32 [[MUL1]], [[AND]]
 ; CHECK-NEXT:    ret i32 [[MUL2]]
@@ -552,8 +551,7 @@ define i32 @or_to_nxor_multiuse(i32 %a,
 ; CHECK-NEXT:    [[AND:%.*]] = and i32 [[A:%.*]], [[B:%.*]]
 ; CHECK-NEXT:    [[OR:%.*]] = or i32 [[A]], [[B]]
 ; CHECK-NEXT:    [[NOTOR:%.*]] = xor i32 [[OR]], -1
-; CHECK-NEXT:    [[TMP1:%.*]] = xor i32 [[A]], [[B]]
-; CHECK-NEXT:    [[OR2:%.*]] = xor i32 [[TMP1]], -1
+; CHECK-NEXT:    [[OR2:%.*]] = or i32 [[AND]], [[NOTOR]]
 ; CHECK-NEXT:    [[MUL1:%.*]] = mul i32 [[AND]], [[NOTOR]]
 ; CHECK-NEXT:    [[MUL2:%.*]] = mul i32 [[MUL1]], [[OR2]]
 ; CHECK-NEXT:    ret i32 [[MUL2]]