Add a comment to describe why vector shuffles are legalized to custom DAG nodes.

[oota-llvm.git] / lib / Analysis / ValueTracking.cpp

diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index b392b7ef558c36fcbd0f1858ca6679d6a0d928ad..af8649499b2f055f74609c6f1ec8c71578dc0e90 100644 (file)
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -81,8 +81,16 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask,
   // The address of an aligned GlobalValue has trailing zeros.
   if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
     unsigned Align = GV->getAlignment();
-    if (Align == 0 && TD && GV->getType()->getElementType()->isSized()) 
-      Align = TD->getPrefTypeAlignment(GV->getType()->getElementType());
+    if (Align == 0 && TD && GV->getType()->getElementType()->isSized()) {
+      const Type *ObjectType = GV->getType()->getElementType();
+      // If the object is defined in the current Module, we'll be giving
+      // it the preferred alignment. Otherwise, we have to assume that it
+      // may only have the minimum ABI alignment.
+      if (!GV->isDeclaration() && !GV->mayBeOverridden())
+        Align = TD->getPrefTypeAlignment(ObjectType);
+      else
+        Align = TD->getABITypeAlignment(ObjectType);
+    }
     if (Align > 0)
       KnownZero = Mask & APInt::getLowBitsSet(BitWidth,
                                               CountTrailingZeros_32(Align));
@@ -800,15 +808,11 @@ bool llvm::CannotBeNegativeZero(const Value *V, unsigned Depth) {
   if (const CallInst *CI = dyn_cast<CallInst>(I))
     if (const Function *F = CI->getCalledFunction()) {
       if (F->isDeclaration()) {
-        switch (F->getNameLen()) {
-        case 3:  // abs(x) != -0.0
-          if (!strcmp(F->getNameStart(), "abs")) return true;
-          break;
-        case 4:  // abs[lf](x) != -0.0
-          if (!strcmp(F->getNameStart(), "absf")) return true;
-          if (!strcmp(F->getNameStart(), "absl")) return true;
-          break;
-        }
+        // abs(x) != -0.0
+        if (F->getName() == "abs") return true;
+        // abs[lf](x) != -0.0
+        if (F->getName() == "absf") return true;
+        if (F->getName() == "absl") return true;
       }
     }
   
@@ -821,11 +825,11 @@ bool llvm::CannotBeNegativeZero(const Value *V, unsigned Depth) {
 // indices from Idxs that should be left out when inserting into the resulting
 // struct. To is the result struct built so far, new insertvalue instructions
 // build on that.
-Value *BuildSubAggregate(Value *From, Value* To, const Type *IndexedType,
-                                 SmallVector<unsigned, 10> &Idxs,
-                                 unsigned IdxSkip,
-                                 LLVMContext &Context,
-                                 Instruction *InsertBefore) {
+static Value *BuildSubAggregate(Value *From, Value* To, const Type *IndexedType,
+                                SmallVector<unsigned, 10> &Idxs,
+                                unsigned IdxSkip,
+                                LLVMContext &Context,
+                                Instruction *InsertBefore) {
   const llvm::StructType *STy = llvm::dyn_cast<llvm::StructType>(IndexedType);
   if (STy) {
     // Save the original To argument so we can modify it
@@ -881,14 +885,14 @@ Value *BuildSubAggregate(Value *From, Value* To, const Type *IndexedType,
 // insertvalue instruction somewhere).
 //
 // All inserted insertvalue instructions are inserted before InsertBefore
-Value *BuildSubAggregate(Value *From, const unsigned *idx_begin,
-                         const unsigned *idx_end, LLVMContext &Context,
-                         Instruction *InsertBefore) {
+static Value *BuildSubAggregate(Value *From, const unsigned *idx_begin,
+                                const unsigned *idx_end, LLVMContext &Context,
+                                Instruction *InsertBefore) {
   assert(InsertBefore && "Must have someplace to insert!");
   const Type *IndexedType = ExtractValueInst::getIndexedType(From->getType(),
                                                              idx_begin,
                                                              idx_end);
-  Value *To = Context.getUndef(IndexedType);
+  Value *To = UndefValue::get(IndexedType);
   SmallVector<unsigned, 10> Idxs(idx_begin, idx_end);
   unsigned IdxSkip = Idxs.size();
 
@@ -917,11 +921,11 @@ Value *llvm::FindInsertedValue(Value *V, const unsigned *idx_begin,
   const CompositeType *PTy = cast<CompositeType>(V->getType());
 
   if (isa<UndefValue>(V))
-    return Context.getUndef(ExtractValueInst::getIndexedType(PTy,
+    return UndefValue::get(ExtractValueInst::getIndexedType(PTy,
                                                               idx_begin,
                                                               idx_end));
   else if (isa<ConstantAggregateZero>(V))
-    return Context.getNullValue(ExtractValueInst::getIndexedType(PTy, 
+    return Constant::getNullValue(ExtractValueInst::getIndexedType(PTy, 
                                                                   idx_begin,
                                                                   idx_end));
   else if (Constant *C = dyn_cast<Constant>(V)) {