Revert some fastcomp changes

lib/IR/Verifier.cpp

@@ -606,10 +606,10 @@ void Verifier::visitGlobalVariable(const GlobalVariable &GV) {
              GV.hasAvailableExternallyLinkage(),
          "Global is marked as dllimport, but not external", &GV);
 
-  //if (!GV.hasInitializer()) { // XXX EMSCRIPTEN - do not do extra verification below, 40x slower linking on some big projects
+  if (!GV.hasInitializer()) {
     visitGlobalValue(GV);
     return;
-  //}
+  }
 
   // Walk any aggregate initializers looking for bitcasts between address spaces
   visitConstantExprsRecursively(GV.getInitializer());

lib/Transforms/IPO/GlobalOpt.cpp

@@ -1547,61 +1547,6 @@ static bool optimizeOnceStoredGlobal(GlobalVariable *GV, Value *StoredOnceVal,
   return false;
 }
 
-/// TryToAddRangeMetadata - At this point, we have learned that the only
-/// two values ever stored into GV are its initializer and OtherVal.  See if we
-/// can annotate loads from it with range metadata describing this.
-/// This exposes the values to other scalar optimizations.
-static bool TryToAddRangeMetadata(GlobalVariable *GV, Constant *OtherVal) {
-  Type *GVElType = GV->getType()->getElementType();
-
-  // If GVElType is already i1, it already has a minimal range. If the type of
-  // the GV is an FP value, pointer or vector, don't do this optimization
-  // because range metadata is currently only supported on scalar integers.
-  if (GVElType == Type::getInt1Ty(GV->getContext()) ||
-      GVElType->isFloatingPointTy() ||
-      GVElType->isPointerTy() || GVElType->isVectorTy())
-    return false;
-
-  // Walk the use list of the global seeing if all the uses are load or store.
-  // If there is anything else, bail out.
-  for (User *U : GV->users())
-    if (!isa<LoadInst>(U) && !isa<StoreInst>(U))
-      return false;
-
-  Constant *InitVal = GV->getInitializer();
-  assert(InitVal->getType() != Type::getInt1Ty(GV->getContext()) &&
-         "No reason to add range metadata!");
-
-  // The MD_range metadata only supports absolute integer constants.
-  if (!isa<ConstantInt>(InitVal) || !isa<ConstantInt>(OtherVal))
-    return false;
-
-  DEBUG(dbgs() << "   *** ADDING RANGE METADATA: " << *GV);
-
-  for (Value::user_iterator I = GV->user_begin(), E = GV->user_end(); I != E; ++I){
-    Instruction *UI = cast<Instruction>(*I);
-    if (LoadInst *LI = dyn_cast<LoadInst>(UI)) {
-      // If we already have a range, don't add a new one, so that GlobalOpt
-      // terminates. In theory, we could merge the two ranges.
-      if (LI->getMetadata(LLVMContext::MD_range))
-        return false;
-      // Add range metadata to the load. We have two possible values, and we
-      // need to create a half-open range. The range can wrap, so we can use
-      // either signed or unsigned; we pick signed because it might be prettier
-      // in common cases.
-      Constant *Cmp = ConstantExpr::getICmp(ICmpInst::ICMP_SLT, InitVal, OtherVal);
-      Constant *One = ConstantInt::get(LI->getType(), 1);
-      SmallVector<Metadata *, 2> NewOps;
-      NewOps.push_back(ConstantAsMetadata::get(ConstantExpr::getSelect(Cmp, InitVal, OtherVal)));
-      NewOps.push_back(ConstantAsMetadata::get(ConstantExpr::getAdd(ConstantExpr::getSelect(Cmp, OtherVal, InitVal), One)));
-      MDNode *MD = MDNode::get(LI->getContext(), NewOps);
-      LI->setMetadata(LLVMContext::MD_range, MD);
-    }
-  }
-
-  return true;
-}
-
 /// At this point, we have learned that the only two values ever stored into GV
 /// are its initializer and OtherVal.  See if we can shrink the global into a
 /// boolean and select between the two values whenever it is used.  This exposes
@@ -1981,10 +1926,9 @@ static bool processInternalGlobal(
 
     // Otherwise, if the global was not a boolean, we can shrink it to be a
     // boolean.
-    // XXX EMSCRIPTEN - add range metadata instead
     if (Constant *SOVConstant = dyn_cast<Constant>(GS.StoredOnceValue)) {
       if (GS.Ordering == AtomicOrdering::NotAtomic) {
-        if (TryToAddRangeMetadata(GV, SOVConstant)) { // XXX EMSCRIPTEN
+        if (TryToShrinkGlobalToBoolean(GV, SOVConstant)) {
           ++NumShrunkToBool;
           return true;
         }

lib/Transforms/InstCombine/InstCombineVectorOps.cpp

@@ -1249,17 +1249,7 @@ Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
 
   // If the result mask is equal to one of the original shuffle masks,
   // or is a splat, do the replacement.
-  //
-  // XXX EMSCRIPTEN: Add '|| true' so that we always do the replacement.
-  // We're targetting SIMD.js, so there's less of an expectation that a
-  // particular shuffle mask will always map onto a particular instruction on
-  // a particular ISA because we aren't targetting a particular ISA (what the
-  // JS engine does is another story). We may wish to re-evaluate this choice
-  // as we move on to higher-element-count vectors, but especially for now this
-  // is quite desirable.
-  if (isSplat || newMask == LHSMask || newMask == RHSMask || newMask == Mask ||
-      true)
-  {
+  if (isSplat || newMask == LHSMask || newMask == RHSMask || newMask == Mask) {
     SmallVector<Constant*, 16> Elts;
     for (unsigned i = 0, e = newMask.size(); i != e; ++i) {
       if (newMask[i] < 0) {