[PatternMatch] Add m_c_DisjointOr (NFC)

Add commutative variant of m_DisjointOr.

Author: nikic

llvm/include/llvm/IR/PatternMatch.h

@@ -1239,7 +1239,7 @@ inline SpecificBinaryOp_match<LHS, RHS> m_BinOp(unsigned Opcode, const LHS &L,
   return SpecificBinaryOp_match<LHS, RHS>(Opcode, L, R);
 }
 
-template <typename LHS, typename RHS>
+template <typename LHS, typename RHS, bool Commutable = false>
 struct DisjointOr_match {
   LHS L;
   RHS R;
@@ -1251,7 +1251,9 @@ struct DisjointOr_match {
       assert(PDI->getOpcode() == Instruction::Or && "Only or can be disjoint");
       if (!PDI->isDisjoint())
         return false;
-      return L.match(PDI->getOperand(0)) && R.match(PDI->getOperand(1));
+      return (L.match(PDI->getOperand(0)) && R.match(PDI->getOperand(1))) ||
+             (Commutable && L.match(PDI->getOperand(1)) &&
+              R.match(PDI->getOperand(0)));
     }
     return false;
   }
@@ -1262,6 +1264,12 @@ inline DisjointOr_match<LHS, RHS> m_DisjointOr(const LHS &L, const RHS &R) {
   return DisjointOr_match<LHS, RHS>(L, R);
 }
 
+template <typename LHS, typename RHS>
+inline DisjointOr_match<LHS, RHS, true> m_c_DisjointOr(const LHS &L,
+                                                       const RHS &R) {
+  return DisjointOr_match<LHS, RHS, true>(L, R);
+}
+
 //===----------------------------------------------------------------------===//
 // Class that matches a group of binary opcodes.
 //

llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp

@@ -3393,9 +3393,8 @@ Instruction *InstCombinerImpl::visitOr(BinaryOperator &I) {
 
   // If the operands have no common bits set:
   // or (mul X, Y), X --> add (mul X, Y), X --> mul X, (Y + 1)
-  if (match(&I,
-            m_c_Or(m_OneUse(m_Mul(m_Value(X), m_Value(Y))), m_Deferred(X))) &&
-      cast<PossiblyDisjointInst>(I).isDisjoint()) {
+  if (match(&I, m_c_DisjointOr(m_OneUse(m_Mul(m_Value(X), m_Value(Y))),
+                               m_Deferred(X)))) {
     Value *IncrementY = Builder.CreateAdd(Y, ConstantInt::get(Ty, 1));
     return BinaryOperator::CreateMul(X, IncrementY);
   }