[ValueTracking] Checking haveNoCommonBitsSet for (x & y) and ~(x | y)

This one tries to fix:
https://github.com/llvm/llvm-project/issues/53357.

Simply, this one would check (x & y) and ~(x | y) in
haveNoCommonBitsSet. Since they shouldn't have common bits (we could
traverse the case by enumerating), and we could convert this one to (x &
y) | ~(x | y) . Then the compiler could handle it in
InstCombineAndOrXor.
Further more, since ((x & y) + (~x & ~y)) would be converted to ((x & y)
+ ~(x | y)), this patch would fix it too.

https://alive2.llvm.org/ce/z/qsKzRS

Reviewed By: spatel, xbolva00, RKSimon, lebedev.ri

Differential Revision: https://reviews.llvm.org/D118094

1 files changed, 19 insertions, 7 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 2fd4565..ef84e0c 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -275,13 +275,25 @@ bool llvm::haveNoCommonBitsSet(const Value *LHS, const Value *RHS,
   assert(LHS->getType()->isIntOrIntVectorTy() &&
          "LHS and RHS should be integers");
   // 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;
+  {
+    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;
+  }
+  // Look for: (A & B) op ~(A | B)
+  {
+    Value *A, *B;
+    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;
+  }
   IntegerType *IT = cast<IntegerType>(LHS->getType()->getScalarType());
   KnownBits LHSKnown(IT->getBitWidth());
   KnownBits RHSKnown(IT->getBitWidth());