X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FConstantFolding.cpp;h=68a55b6b94d50b80b682522c29f8ec6c9b3b5ce2;hb=48f17ba2a611d197082d4de730b646a4ecf68df4;hp=82b406f204416f48d8702363798630d354fd68fc;hpb=e58391073f6e17cd1024f737618a6f6b8d1323ce;p=oota-llvm.git

diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index 82b406f2044..68a55b6b94d 100644
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -30,7 +30,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/GetElementPtrTypeIterator.h"
 #include "llvm/Support/MathExtras.h"
-#include "llvm/System/FEnv.h"
+#include "llvm/Support/FEnv.h"
 #include <cerrno>
 #include <cmath>
 using namespace llvm;
@@ -610,10 +610,8 @@ static Constant *SymbolicallyEvaluateGEP(Constant *const *Ops, unsigned NumOps,
   APInt BasePtr(BitWidth, 0);
   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr))
     if (CE->getOpcode() == Instruction::IntToPtr)
-      if (ConstantInt *Base = dyn_cast<ConstantInt>(CE->getOperand(0))) {
-        BasePtr = Base->getValue();
-        BasePtr.zextOrTrunc(BitWidth);
-      }
+      if (ConstantInt *Base = dyn_cast<ConstantInt>(CE->getOperand(0)))
+        BasePtr = Base->getValue().zextOrTrunc(BitWidth);
   if (Ptr->isNullValue() || BasePtr != 0) {
     Constant *C = ConstantInt::get(Ptr->getContext(), Offset+BasePtr);
     return ConstantExpr::getIntToPtr(C, ResultTy);
@@ -695,22 +693,23 @@ static Constant *SymbolicallyEvaluateGEP(Constant *const *Ops, unsigned NumOps,
 // Constant Folding public APIs
 //===----------------------------------------------------------------------===//
 
-
-/// ConstantFoldInstruction - Attempt to constant fold the specified
-/// instruction.  If successful, the constant result is returned, if not, null
-/// is returned.  Note that this function can only fail when attempting to fold
-/// instructions like loads and stores, which have no constant expression form.
-///
+/// ConstantFoldInstruction - Try to constant fold the specified instruction.
+/// If successful, the constant result is returned, if not, null is returned.
+/// Note that this fails if not all of the operands are constant.  Otherwise,
+/// this function can only fail when attempting to fold instructions like loads
+/// and stores, which have no constant expression form.
 Constant *llvm::ConstantFoldInstruction(Instruction *I, const TargetData *TD) {
-  // Handle PHI nodes specially here...
+  // Handle PHI nodes quickly here...
   if (PHINode *PN = dyn_cast<PHINode>(I)) {
     Constant *CommonValue = 0;
 
     for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
       Value *Incoming = PN->getIncomingValue(i);
-      // If the incoming value is equal to the phi node itself or is undef then
-      // skip it.
-      if (Incoming == PN || isa<UndefValue>(Incoming))
+      // If the incoming value is undef then skip it.  Note that while we could
+      // skip the value if it is equal to the phi node itself we choose not to
+      // because that would break the rule that constant folding only applies if
+      // all operands are constants.
+      if (isa<UndefValue>(Incoming))
         continue;
       // If the incoming value is not a constant, or is a different constant to
       // the one we saw previously, then give up.
@@ -739,7 +738,18 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, const TargetData *TD) {
   
   if (const LoadInst *LI = dyn_cast<LoadInst>(I))
     return ConstantFoldLoadInst(LI, TD);
-  
+
+  if (InsertValueInst *IVI = dyn_cast<InsertValueInst>(I))
+    return ConstantExpr::getInsertValue(
+                                cast<Constant>(IVI->getAggregateOperand()),
+                                cast<Constant>(IVI->getInsertedValueOperand()),
+                                IVI->idx_begin(), IVI->getNumIndices());
+
+  if (ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(I))
+    return ConstantExpr::getExtractValue(
+                                    cast<Constant>(EVI->getAggregateOperand()),
+                                    EVI->idx_begin(), EVI->getNumIndices());
+
   return ConstantFoldInstOperands(I->getOpcode(), I->getType(),
                                   Ops.data(), Ops.size(), TD);
 }