Fix InstCombine/2007-01-18-VectorInfLoop.ll, a case where instcombine

infinitely loops.

llvm-svn: 33343

1 files changed, 9 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
index 48eaef59e72..324ec8aac04 100644
--- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -3062,10 +3062,16 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
   // See if we can simplify any instructions used by the instruction whose sole 
   // purpose is to compute bits we don't care about.
   uint64_t KnownZero, KnownOne;
-  if (!isa<PackedType>(I.getType()) &&
-      SimplifyDemandedBits(&I, I.getType()->getIntegerTypeMask(),
-                           KnownZero, KnownOne))
+  if (!isa<PackedType>(I.getType())) {
+    if (SimplifyDemandedBits(&I, I.getType()->getIntegerTypeMask(),
+                             KnownZero, KnownOne))
     return &I;
+  } else {
+    if (ConstantPacked *CP = dyn_cast<ConstantPacked>(Op1)) {
+      if (CP->isAllOnesValue())
+        return ReplaceInstUsesWith(I, I.getOperand(0));
+    }
+  }
   
   if (ConstantInt *AndRHS = dyn_cast<ConstantInt>(Op1)) {
     uint64_t AndRHSMask = AndRHS->getZExtValue();