Fix a fixme in CondPropagate.cpp by moving a PhiNode optimization into

BasicBlock's removePredecessor routine.  This requires shuffling around
the definition and implementation of hasContantValue from Utils.h,cpp into
Instructions.h,cpp

llvm-svn: 22664

2 files changed, 1 insertions, 36 deletions

diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 4ce9d8f11a1..9744af3c605 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -406,37 +406,3 @@ bool llvm::dceInstruction(BasicBlock::iterator &BBI) {
   }
   return false;
 }
-
-//===----------------------------------------------------------------------===//
-//  PHI Instruction Simplification
-//
-
-/// hasConstantValue - If the specified PHI node always merges together the same
-/// value, return the value, otherwise return null.
-///
-Value *llvm::hasConstantValue(PHINode *PN) {
-  // If the PHI node only has one incoming value, eliminate the PHI node...
-  if (PN->getNumIncomingValues() == 1)
-    return PN->getIncomingValue(0);
-
-  // Otherwise if all of the incoming values are the same for the PHI, replace
-  // the PHI node with the incoming value.
-  //
-  Value *InVal = 0;
-  for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
-    if (PN->getIncomingValue(i) != PN &&  // Not the PHI node itself...
-        !isa<UndefValue>(PN->getIncomingValue(i)))
-      if (InVal && PN->getIncomingValue(i) != InVal)
-        return 0;  // Not the same, bail out.
-      else
-        InVal = PN->getIncomingValue(i);
-
-  // The only case that could cause InVal to be null is if we have a PHI node
-  // that only has entries for itself.  In this case, there is no entry into the
-  // loop, so kill the PHI.
-  //
-  if (InVal == 0) InVal = UndefValue::get(PN->getType());
-
-  // All of the incoming values are the same, return the value now.
-  return InVal;
-}
diff --git a/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp b/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
index 1edc1193766..bb7f8680933 100644
--- a/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
+++ b/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
@@ -24,7 +24,6 @@
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/AliasSetTracker.h"
 #include "llvm/ADT/StringExtras.h"
-#include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Support/CFG.h"
 #include "llvm/Support/StableBasicBlockNumbering.h"
 #include <algorithm>
@@ -348,7 +347,7 @@ void PromoteMem2Reg::run() {
     PHINode *SomePHI = 0;
     for (unsigned i = 0, e = PNs.size(); i != e; ++i)
       if (PNs[i]) {
-        if (Value *V = hasConstantValue(PNs[i])) {
+        if (Value *V = PNs[i]->hasConstantValue()) {
           if (!isa<Instruction>(V) || dominates(cast<Instruction>(V), PNs[i])) {
             if (AST && isa<PointerType>(PNs[i]->getType()))
               AST->deleteValue(PNs[i]);