[InstCombine] Cleanup some duplicated one use checks

[craig.topper]

Summary

These 4 patterns have the same one use check repeated twice for each. Once without a cast and one with. But the cast has no effect on what method is called.

For the OR case I believe it is always profitable regardless of the number of uses since we'll never increase the instruction count.

For the AND case I believe it is profitable if the pair of xors has one use such that we'll get rid of it completely. Or if the C value is something freely invertible, in which case the not doesn't cost anything.

[spatel]

LGTM.

lib/Transforms/InstCombine/InstCombineAndOrXor.cpp

if (Instruction *DeMorgan = matchDeMorgansLaws(I, *Builder))
     if (match(Op0, m_c_Or(m_Not(m_Specific(Op1)), m_Value(A))))
       return BinaryOperator::CreateAnd(A, Op1);
     if (match(Op1, m_c_Or(m_Not(m_Specific(Op0)), m_Value(A))))
       return BinaryOperator::CreateAnd(A, Op0);
 
     // (A ^ B) & ((B ^ C) ^ A) -> (A ^ B) & ~C
     if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
       if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A))))
-        if (Op1->hasOneUse() || cast<BinaryOperator>(Op1)->hasOneUse())
+        if (Op1->hasOneUse() || IsFreeToInvert(C, C->hasOneUse()))
           return BinaryOperator::CreateAnd(Op0, Builder->CreateNot(C));
 
     // ((A ^ C) ^ B) & (B ^ A) -> (B ^ A) & ~C
     if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B))))
       if (match(Op1, m_Xor(m_Specific(B), m_Specific(A))))
-        if (Op0->hasOneUse() || cast<BinaryOperator>(Op0)->hasOneUse())
+        if (Op0->hasOneUse() || IsFreeToInvert(C, C->hasOneUse()))
           return BinaryOperator::CreateAnd(Op1, Builder->CreateNot(C));
 
     // (A | B) & ((~A) ^ B) -> (A & B)
     // (A | B) & (B ^ (~A)) -> (A & B)
     // (B | A) & ((~A) ^ B) -> (A & B)
     // (B | A) & (B ^ (~A)) -> (A & B)
     if (match(Op1, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
         match(Op0, m_c_Or(m_Specific(A), m_Specific(B))))
if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
     if (match(B, m_Xor(m_Specific(A), m_Value(V1))) ||
         match(B, m_Xor(m_Value(V1), m_Specific(A)))) {
       Instruction *Ret = FoldXorWithConstants(I, Op0, A, V1, D);
       if (Ret) return Ret;
     }
   }
 
   // (A ^ B) | ((B ^ C) ^ A) -> (A ^ B) | C
-  // FIXME: The two hasOneUse calls here are the same call, maybe we were
-  // supposed to check Op1->operand(0)?
   if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
     if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A))))
-      if (Op1->hasOneUse() || cast<BinaryOperator>(Op1)->hasOneUse())
-        return BinaryOperator::CreateOr(Op0, C);
 
   // ((A ^ C) ^ B) | (B ^ A) -> (B ^ A) | C
-  // FIXME: The two hasOneUse calls here are the same call, maybe we were
-  // supposed to check Op0->operand(0)?
   if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B))))
     if (match(Op1, m_Xor(m_Specific(B), m_Specific(A))))
-      if (Op0->hasOneUse() || cast<BinaryOperator>(Op0)->hasOneUse())
-        return BinaryOperator::CreateOr(Op1, C);
 
   // ((B | C) & A) | B -> B | (A & C)
   if (match(Op0, m_And(m_Or(m_Specific(Op1), m_Value(C)), m_Value(A))))
     return BinaryOperator::CreateOr(Op1, Builder->CreateAnd(A, C));
 
   if (Instruction *DeMorgan = matchDeMorgansLaws(I, *Builder))
     return DeMorgan;
 

test/Transforms/InstCombine/or-xor.ll

;
   ret i8 %or2
 }
 
 define i8 @test17(i8 %A, i8 %B) {
 ; CHECK-LABEL: @test17(
 ; CHECK-NEXT:    [[XOR1:%.*]] = xor i8 [[B:%.*]], [[A:%.*]]
 ; CHECK-NEXT:    [[NOT:%.*]] = xor i8 [[A]], 33
 ; CHECK-NEXT:    [[XOR2:%.*]] = xor i8 [[NOT]], [[B]]
-; CHECK-NEXT:    [[OR:%.*]] = or i8 [[XOR1]], [[XOR2]]
+; CHECK-NEXT:    [[OR:%.*]] = or i8 [[XOR1]], 33
 ; CHECK-NEXT:    [[RES:%.*]] = mul i8 [[OR]], [[XOR2]]
 ; CHECK-NEXT:    ret i8 [[RES]]
 ;
   %xor1 = xor i8 %B, %A
   %not = xor i8 %A, 33
   %xor2 = xor i8 %not, %B
   %or = or i8 %xor1, %xor2
   %res = mul i8 %or, %xor2 ; to increase the use count for the xor
   ret i8 %res
 }
 
 define i8 @test18(i8 %A, i8 %B) {
 ; CHECK-LABEL: @test18(
 ; CHECK-NEXT:    [[XOR1:%.*]] = xor i8 [[B:%.*]], [[A:%.*]]
 ; CHECK-NEXT:    [[NOT:%.*]] = xor i8 [[A]], 33
 ; CHECK-NEXT:    [[XOR2:%.*]] = xor i8 [[NOT]], [[B]]
-; CHECK-NEXT:    [[OR:%.*]] = or i8 [[XOR2]], [[XOR1]]
+; CHECK-NEXT:    [[OR:%.*]] = or i8 [[XOR1]], 33
 ; CHECK-NEXT:    [[RES:%.*]] = mul i8 [[OR]], [[XOR2]]
 ; CHECK-NEXT:    ret i8 [[RES]]
 ;
   %xor1 = xor i8 %B, %A
   %not = xor i8 %A, 33
   %xor2 = xor i8 %not, %B
   %or = or i8 %xor2, %xor1
   %res = mul i8 %or, %xor2 ; to increase the use count for the xor
   ret i8 %res
 }

test/Transforms/InstCombine/xor2.ll

;
   ret i32 %xor
 }
 
 define i8 @test15(i8 %A, i8 %B) {
 ; CHECK-LABEL: @test15(
 ; CHECK-NEXT:    [[XOR1:%.*]] = xor i8 [[B:%.*]], [[A:%.*]]
 ; CHECK-NEXT:    [[NOT:%.*]] = xor i8 [[A]], 33
 ; CHECK-NEXT:    [[XOR2:%.*]] = xor i8 [[NOT]], [[B]]
-; CHECK-NEXT:    [[AND:%.*]] = and i8 [[XOR1]], [[XOR2]]
+; CHECK-NEXT:    [[AND:%.*]] = and i8 [[XOR1]], -34
 ; CHECK-NEXT:    [[RES:%.*]] = mul i8 [[AND]], [[XOR2]]
 ; CHECK-NEXT:    ret i8 [[RES]]
 ;
   %xor1 = xor i8 %B, %A
   %not = xor i8 %A, 33
   %xor2 = xor i8 %not, %B
   %and = and i8 %xor1, %xor2
   %res = mul i8 %and, %xor2 ; to increase the use count for the xor
   ret i8 %res
 }
 
 define i8 @test16(i8 %A, i8 %B) {
 ; CHECK-LABEL: @test16(
 ; CHECK-NEXT:    [[XOR1:%.*]] = xor i8 [[B:%.*]], [[A:%.*]]
 ; CHECK-NEXT:    [[NOT:%.*]] = xor i8 [[A]], 33
 ; CHECK-NEXT:    [[XOR2:%.*]] = xor i8 [[NOT]], [[B]]
-; CHECK-NEXT:    [[AND:%.*]] = and i8 [[XOR2]], [[XOR1]]
+; CHECK-NEXT:    [[AND:%.*]] = and i8 [[XOR1]], -34
 ; CHECK-NEXT:    [[RES:%.*]] = mul i8 [[AND]], [[XOR2]]
 ; CHECK-NEXT:    ret i8 [[RES]]
 ;
   %xor1 = xor i8 %B, %A
   %not = xor i8 %A, 33
   %xor2 = xor i8 %not, %B
   %and = and i8 %xor2, %xor1
   %res = mul i8 %and, %xor2 ; to increase the use count for the xor
   ret i8 %res
 }