Per Chris' suggestion, get rid of the select canonicalization and just add

the corresponding or-icmp-and pattern.  This has the added benefit of doing
the matching earlier, and thus being less susceptible to being confused by
earlier transforms.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108429 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 0 deletions

diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 5876f40834..e19ddd1983 100644
--- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1177,6 +1177,25 @@ Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
     return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
   }
   
+  // (icmp eq (A & C1), 0) | (icmp eq (A & C2), 0) -->
+  // (icmp ne (A & (C1|C2)), (C1|C2))
+  if (LHSCC == ICmpInst::ICMP_EQ && LHSCst->isZero()) {
+    Instruction *I1 = dyn_cast<Instruction>(Val);
+    Instruction *I2 = dyn_cast<Instruction>(Val2);
+    if (I1 && I1->getOpcode() == Instruction::And &&
+        I2 && I2->getOpcode() == Instruction::And &&
+        I1->getOperand(0) == I1->getOperand(0)) {
+      ConstantInt *CI1 = dyn_cast<ConstantInt>(I1->getOperand(1));
+      ConstantInt *CI2 = dyn_cast<ConstantInt>(I2->getOperand(1));
+      if (CI1 && !CI1->isZero() && CI2 && !CI2->isZero() &&
+          CI1->getValue().operator&(CI2->getValue()) == 0) {
+        Constant *ConstOr = ConstantExpr::getOr(CI1, CI2);
+        Value *NewAnd = Builder->CreateAnd(I1->getOperand(0), ConstOr);
+        return Builder->CreateICmp(ICmpInst::ICMP_NE, NewAnd, ConstOr);
+      }
+    }
+  }
+  
   // From here on, we only handle:
   //    (icmp1 A, C1) | (icmp2 A, C2) --> something simpler.
   if (Val != Val2) return 0;