[InstSimplify] with logical ops: (0 == (X | Y)) ? X : 0 --> 0

[Allen]

Summary

This code try to internally match the EQ predicate when their
operands swapped.

[nikic]

This will be canonicalized by InstCombine.

llvm/lib/Analysis/InstructionSimplify.cpp

       return V;
     if (Value *V = simplifySelectWithICmpEq(CmpRHS, CmpLHS, TrueVal, FalseVal,
                                             Q, MaxRecurse))
       return V;
 
     // select(X | Y == 0 ?  X : 0) --> 0 (commuted 2 ways)
     Value *X;
     Value *Y;
-    if (match(CmpLHS, m_Or(m_Value(X), m_Value(Y))) &&
-        match(CmpRHS, m_Zero())) {
+    if ((match(CmpLHS, m_Or(m_Value(X), m_Value(Y))) &&
+         match(CmpRHS, m_Zero())) ||
+        (match(CmpRHS, m_Or(m_Value(X), m_Value(Y))) &&
+         match(CmpLHS, m_Zero()))) {
       // X | Y == 0 implies X == 0 and Y == 0.
-      if (Value *V = simplifySelectWithICmpEq(X, CmpRHS, TrueVal, FalseVal, Q,
-                                              MaxRecurse))
+      if (Value *V =
+              simplifySelectWithICmpEq(X, ConstantInt::get(X->getType(), 0),
+                                       TrueVal, FalseVal, Q, MaxRecurse))
         return V;
-      if (Value *V = simplifySelectWithICmpEq(Y, CmpRHS, TrueVal, FalseVal, Q,
-                                              MaxRecurse))
+      if (Value *V =
+              simplifySelectWithICmpEq(Y, ConstantInt::get(Y->getType(), 0),
+                                       TrueVal, FalseVal, Q, MaxRecurse))
         return V;
     }
   }
 
   if (Pred == ICmpInst::Predicate::ICMP_EQ) {
     Value *X;
     Value *Y;
     // select(X & Y == -1, X or Y, X & Y) -> X & Y

llvm/test/Transforms/InstSimplify/select_or_and.ll

 ; CHECK-NEXT:    ret i32 0
 ;
   %or = or i32 %a, %b
   %tobool = icmp eq i32 %or, 0
   %cond = select i1 %tobool, i32 %a, i32 0
   ret i32 %cond
 }
 
+define i32 @select_icmp_or_eq_swap(i32 %a, i32 %b) {
+; CHECK-LABEL: @select_icmp_or_eq_swap(
+; CHECK-NEXT:    ret i32 0
+;
+  %or = or i32 %a, %b
+  %tobool = icmp eq i32 0, %or  ; swap the icmp operands
+  %cond = select i1 %tobool, i32 %a, i32 0
+  ret i32 %cond
+}
+
 define i32 @select_icmp_or_eq_commuted(i32 %a, i32 %b) {
 ; CHECK-LABEL: @select_icmp_or_eq_commuted(
 ; CHECK-NEXT:    ret i32 0
 ;
   %or = or i32 %a, %b
   %tobool = icmp eq i32 %or, 0
   %cond = select i1 %tobool, i32 %b, i32 0
   ret i32 %cond