This xform is handled by FoldOpIntoPhi in visitCastInst in a more elegant way.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31889 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 968e6ad4e94dc922c769804bc86300ce76594b77..5a586e022b7a5ee2ae35cf1d0a0b85b52d70c953 100644 (file)
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -5784,7 +5784,7 @@ Instruction *InstCombiner::visitCastInst(CastInst &CI) {
       return &CI;
     }
   }
-
+    
   // If we are casting a malloc or alloca to a pointer to a type of the same
   // size, rewrite the allocation instruction to allocate the "right" type.
   //
@@ -7144,35 +7144,6 @@ Instruction *InstCombiner::visitPHINode(PHINode &PN) {
   if (Value *V = PN.hasConstantValue())
     return ReplaceInstUsesWith(PN, V);
 
-  // If the only user of this instruction is a cast instruction, and all of the
-  // incoming values are constants, change this PHI to merge together the casted
-  // constants.
-  if (PN.hasOneUse())
-    if (CastInst *CI = dyn_cast<CastInst>(PN.use_back()))
-      if (CI->getType() != PN.getType()) {  // noop casts will be folded
-        bool AllConstant = true;
-        for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
-          if (!isa<Constant>(PN.getIncomingValue(i))) {
-            AllConstant = false;
-            break;
-          }
-        if (AllConstant) {
-          // Make a new PHI with all casted values.
-          PHINode *New = new PHINode(CI->getType(), PN.getName(), &PN);
-          for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
-            Constant *OldArg = cast<Constant>(PN.getIncomingValue(i));
-            New->addIncoming(ConstantExpr::getCast(OldArg, New->getType()),
-                             PN.getIncomingBlock(i));
-          }
-
-          // Update the cast instruction.
-          CI->setOperand(0, New);
-          WorkList.push_back(CI);    // revisit the cast instruction to fold.
-          WorkList.push_back(New);   // Make sure to revisit the new Phi
-          return &PN;                // PN is now dead!
-        }
-      }
-
   // If all PHI operands are the same operation, pull them through the PHI,
   // reducing code size.
   if (isa<Instruction>(PN.getIncomingValue(0)) &&