Added InstCombine Transform for ((B | C) & A) | B -> B | (A & C)

Transform ((B | C) & A) | B --> B | (A & C)

Z3 Link: http://rise4fun.com/Z3/hP6p

Patch by Sonam Kumari!

Differential Revision: http://reviews.llvm.org/D4865

llvm-svn: 215619

Author: majnemer

llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp

@@ -2124,6 +2124,10 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
       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));
+
   // (X >> Z) | (Y >> Z)  -> (X|Y) >> Z  for all shifts.
   if (BinaryOperator *SI1 = dyn_cast<BinaryOperator>(Op1)) {
     if (BinaryOperator *SI0 = dyn_cast<BinaryOperator>(Op0))

llvm/test/Transforms/InstCombine/or.ll

@@ -469,3 +469,14 @@ define i32 @test44(i32 %a, i32 %b) {
  %or = or i32 %xor, %and
  ret i32 %or
 }
+
+define i32 @test45(i32 %x, i32 %y, i32 %z) {
+; CHECK-LABEL: test45(
+; CHECK-NEXT: %1 = and i32 %x, %z
+; CHECK-NEXT: %or1 = or i32 %1, %y
+; CHECK-NEXT: ret i32 %or1
+  %or = or i32 %y, %z
+  %and = and i32 %x, %or
+  %or1 = or i32 %and, %y
+  ret i32 %or1
+}