[ValueTracking] Reduce duplication in haveNoCommonBitsSet() (NFC)

Extract a function and call it with both operand orders, so that
we don't have to explicitly commute every single pattern.

Author: nikic

llvm/lib/Analysis/ValueTracking.cpp

@@ -186,47 +186,30 @@ KnownBits llvm::computeKnownBits(const Value *V, const APInt &DemandedElts,
       SimplifyQuery(DL, DT, AC, safeCxtI(V, CxtI), UseInstrInfo));
 }
 
-bool llvm::haveNoCommonBitsSet(const WithCache<const Value *> &LHSCache,
-                               const WithCache<const Value *> &RHSCache,
-                               const SimplifyQuery &SQ) {
-  const Value *LHS = LHSCache.getValue();
-  const Value *RHS = RHSCache.getValue();
-
-  assert(LHS->getType() == RHS->getType() &&
-         "LHS and RHS should have the same type");
-  assert(LHS->getType()->isIntOrIntVectorTy() &&
-         "LHS and RHS should be integers");
+static bool haveNoCommonBitsSetSpecialCases(const Value *LHS,
+                                            const Value *RHS) {
   // Look for an inverted mask: (X & ~M) op (Y & M).
   {
     Value *M;
     if (match(LHS, m_c_And(m_Not(m_Value(M)), m_Value())) &&
         match(RHS, m_c_And(m_Specific(M), m_Value())))
       return true;
-    if (match(RHS, m_c_And(m_Not(m_Value(M)), m_Value())) &&
-        match(LHS, m_c_And(m_Specific(M), m_Value())))
-      return true;
   }
 
   // X op (Y & ~X)
-  if (match(RHS, m_c_And(m_Not(m_Specific(LHS)), m_Value())) ||
-      match(LHS, m_c_And(m_Not(m_Specific(RHS)), m_Value())))
+  if (match(RHS, m_c_And(m_Not(m_Specific(LHS)), m_Value())))
     return true;
 
   // X op ((X & Y) ^ Y) -- this is the canonical form of the previous pattern
   // for constant Y.
   Value *Y;
-  if (match(RHS,
-            m_c_Xor(m_c_And(m_Specific(LHS), m_Value(Y)), m_Deferred(Y))) ||
-      match(LHS, m_c_Xor(m_c_And(m_Specific(RHS), m_Value(Y)), m_Deferred(Y))))
+  if (match(RHS, m_c_Xor(m_c_And(m_Specific(LHS), m_Value(Y)), m_Deferred(Y))))
     return true;
 
   // Peek through extends to find a 'not' of the other side:
   // (ext Y) op ext(~Y)
-  // (ext ~Y) op ext(Y)
-  if ((match(LHS, m_ZExtOrSExt(m_Value(Y))) &&
-       match(RHS, m_ZExtOrSExt(m_Not(m_Specific(Y))))) ||
-      (match(RHS, m_ZExtOrSExt(m_Value(Y))) &&
-       match(LHS, m_ZExtOrSExt(m_Not(m_Specific(Y))))))
+  if (match(LHS, m_ZExtOrSExt(m_Value(Y))) &&
+      match(RHS, m_ZExtOrSExt(m_Not(m_Specific(Y)))))
     return true;
 
   // Look for: (A & B) op ~(A | B)
@@ -235,11 +218,26 @@ bool llvm::haveNoCommonBitsSet(const WithCache<const Value *> &LHSCache,
     if (match(LHS, m_And(m_Value(A), m_Value(B))) &&
         match(RHS, m_Not(m_c_Or(m_Specific(A), m_Specific(B)))))
       return true;
-    if (match(RHS, m_And(m_Value(A), m_Value(B))) &&
-        match(LHS, m_Not(m_c_Or(m_Specific(A), m_Specific(B)))))
-      return true;
   }
 
+  return false;
+}
+
+bool llvm::haveNoCommonBitsSet(const WithCache<const Value *> &LHSCache,
+                               const WithCache<const Value *> &RHSCache,
+                               const SimplifyQuery &SQ) {
+  const Value *LHS = LHSCache.getValue();
+  const Value *RHS = RHSCache.getValue();
+
+  assert(LHS->getType() == RHS->getType() &&
+         "LHS and RHS should have the same type");
+  assert(LHS->getType()->isIntOrIntVectorTy() &&
+         "LHS and RHS should be integers");
+
+  if (haveNoCommonBitsSetSpecialCases(LHS, RHS) ||
+      haveNoCommonBitsSetSpecialCases(RHS, LHS))
+    return true;
+
   return KnownBits::haveNoCommonBitsSet(LHSCache.getKnownBits(SQ),
                                         RHSCache.getKnownBits(SQ));
 }