Upgrade our copy of clang and llvm to 3.6.1 release.

This release contains the following cherry-picked revisions from
upstream trunk:

  226124 226151 226164 226165 226166 226407 226408 226409 226652
  226905 226983 227084 227087 227089 227208 227209 227210 227211
  227212 227213 227214 227269 227430 227482 227503 227519 227574
  227822 227986 227987 227988 227989 227990 228037 228038 228039
  228040 228188 228189 228190 228273 228372 228373 228374 228403
  228765 228848 228918 229223 229225 229226 229227 229228 229230
  229234 229235 229236 229238 229239 229413 229507 229680 229750
  229751 229752 229911 230146 230147 230235 230253 230255 230469
  230500 230564 230603 230657 230742 230748 230956 231219 231237
  231245 231259 231280 231451 231563 231601 231658 231659 231662
  231984 231986 232046 232085 232142 232176 232179 232189 232382
  232386 232389 232425 232438 232443 232675 232786 232797 232943
  232957 233075 233080 233351 233353 233409 233410 233508 233584
  233819 233904 234629 234636 234891 234975 234977 235524 235641
  235662 235931 236099 236306 236307

Please note that from 3.5.0 onwards, clang and llvm require C++11
support to build; see UPDATING for more information.

3 files changed, 19 insertions, 13 deletions

diff --git a/contrib/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp b/contrib/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
index cb965fb..60b541f 100644
--- a/contrib/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
+++ b/contrib/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
@@ -47,6 +47,8 @@ using namespace llvm;
 static cl::opt<std::string>
 DefaultGCOVVersion("default-gcov-version", cl::init("402*"), cl::Hidden,
                    cl::ValueRequired);
+static cl::opt<bool> DefaultExitBlockBeforeBody("gcov-exit-block-before-body",
+                                                cl::init(false), cl::Hidden);
 
 GCOVOptions GCOVOptions::getDefault() {
   GCOVOptions Options;
@@ -312,7 +314,7 @@ namespace {
   class GCOVFunction : public GCOVRecord {
    public:
      GCOVFunction(DISubprogram SP, raw_ostream *os, uint32_t Ident,
-                  bool UseCfgChecksum)
+                  bool UseCfgChecksum, bool ExitBlockBeforeBody)
          : SP(SP), Ident(Ident), UseCfgChecksum(UseCfgChecksum), CfgChecksum(0),
            ReturnBlock(1, os) {
       this->os = os;
@@ -322,11 +324,13 @@ namespace {
 
       uint32_t i = 0;
       for (auto &BB : *F) {
-        // Skip index 1 (0, 2, 3, 4, ...) because that's assigned to the
-        // ReturnBlock.
-        bool first = i == 0;
-        Blocks.insert(std::make_pair(&BB, GCOVBlock(i++ + !first, os)));
+        // Skip index 1 if it's assigned to the ReturnBlock.
+        if (i == 1 && ExitBlockBeforeBody)
+          ++i;
+        Blocks.insert(std::make_pair(&BB, GCOVBlock(i++, os)));
       }
+      if (!ExitBlockBeforeBody)
+        ReturnBlock.Number = i;
 
       std::string FunctionNameAndLine;
       raw_string_ostream FNLOS(FunctionNameAndLine);
@@ -469,7 +473,7 @@ static bool functionHasLines(Function *F) {
       if (Loc.isUnknown()) continue;
 
       // Artificial lines such as calls to the global constructors.
-      if (Loc.getLine() == 0) continue; 
+      if (Loc.getLine() == 0) continue;
 
       return true;
     }
@@ -513,7 +517,8 @@ void GCOVProfiler::emitProfileNotes() {
       EntryBlock.splitBasicBlock(It);
 
       Funcs.push_back(make_unique<GCOVFunction>(SP, &out, FunctionIdent++,
-                                                Options.UseCfgChecksum));
+                                                Options.UseCfgChecksum,
+                                                DefaultExitBlockBeforeBody));
       GCOVFunction &Func = *Funcs.back();
 
       for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
diff --git a/contrib/llvm/lib/Transforms/Scalar/GVN.cpp b/contrib/llvm/lib/Transforms/Scalar/GVN.cpp
index ac13eeb..1ed14d0 100644
--- a/contrib/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/contrib/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -2183,12 +2183,16 @@ bool GVN::propagateEquality(Value *LHS, Value *RHS,
       // Handle the floating point versions of equality comparisons too.
       if ((isKnownTrue && Cmp->getPredicate() == CmpInst::FCMP_OEQ) ||
           (isKnownFalse && Cmp->getPredicate() == CmpInst::FCMP_UNE)) {
-        // Floating point -0.0 and 0.0 compare equal, so we can't
-        // propagate a constant based on that comparison.
+
+        // Floating point -0.0 and 0.0 compare equal, so we can only
+        // propagate values if we know that we have a constant and that
+        // its value is non-zero.
+        
         // FIXME: We should do this optimization if 'no signed zeros' is
         // applicable via an instruction-level fast-math-flag or some other
         // indicator that relaxed FP semantics are being used.
-        if (!isa<ConstantFP>(Op1) || !cast<ConstantFP>(Op1)->isZero())
+
+        if (isa<ConstantFP>(Op1) && !cast<ConstantFP>(Op1)->isZero())
           Worklist.push_back(std::make_pair(Op0, Op1));
       }
  
diff --git a/contrib/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/contrib/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index 6cb91a1..d54c09a 100644
--- a/contrib/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/contrib/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -288,14 +288,11 @@ bool SimplifyIndvar::strengthenOverflowingOperation(BinaryOperator *BO,
 
   IntegerType *IT = cast<IntegerType>(IVOperand->getType());
   Value *OtherOperand = nullptr;
-  int OtherOperandIdx = -1;
   if (BO->getOperand(0) == IVOperand) {
     OtherOperand = BO->getOperand(1);
-    OtherOperandIdx = 1;
   } else {
     assert(BO->getOperand(1) == IVOperand && "only other use!");
     OtherOperand = BO->getOperand(0);
-    OtherOperandIdx = 0;
   }
 
   bool Changed = false;