MFC 261991:

Upgrade our copy of llvm/clang to 3.4 release.  This version supports
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.

The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3.  The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>

MFC 262121 (by emaste):

Update lldb for clang/llvm 3.4 import

This commit largely restores the lldb source to the upstream r196259
snapshot with the addition of threaded inferior support and a few bug
fixes.

Specific upstream lldb revisions restored include:
   SVN      git
  181387  779e6ac
  181703  7bef4e2
  182099  b31044e
  182650  f2dcf35
  182683  0d91b80
  183862  15c1774
  183929  99447a6
  184177  0b2934b
  184948  4dc3761
  184954  007e7bc
  186990  eebd175

Sponsored by:	DARPA, AFRL

MFC 262186 (by emaste):

Fix mismerge in r262121

A break statement was lost in the merge.  The error had no functional
impact, but restore it to reduce the diff against upstream.

MFC 262303:

Pull in r197521 from upstream clang trunk (by rdivacky):

  Use the integrated assembler by default on FreeBSD/ppc and ppc64.

Requested by:	jhibbits

MFC 262611:

Pull in r196874 from upstream llvm trunk:

  Fix a crash that occurs when PWD is invalid.

  MCJIT needs to be able to run in hostile environments, even when PWD
  is invalid. There's no need to crash MCJIT in this case.

  The obvious fix is to simply leave MCContext's CompilationDir empty
  when PWD can't be determined. This way, MCJIT clients,
  and other clients that link with LLVM don't need a valid working directory.

  If we do want to guarantee valid CompilationDir, that should be done
  only for clients of getCompilationDir(). This is as simple as checking
  for an empty string.

  The only current use of getCompilationDir is EmitGenDwarfInfo, which
  won't conceivably run with an invalid working dir. However, in the
  purely hypothetically and untestable case that this happens, the
  AT_comp_dir will be omitted from the compilation_unit DIE.

This should help fix assertions occurring with ports-mgmt/tinderbox,
when it is using jails, and sometimes invalidates clang's current
working directory.

Reported by:	decke

MFC 262809:

Pull in r203007 from upstream clang trunk:

  Don't produce an alias between destructors with different calling conventions.

  Fixes pr19007.

(Please note that is an LLVM PR identifier, not a FreeBSD one.)

This should fix Firefox and/or libxul crashes (due to problems with
regparm/stdcall calling conventions) on i386.

Reported by:	multiple users on freebsd-current
PR:		bin/187103

MFC 263048:

Repair recognition of "CC" as an alias for the C++ compiler, since it
was silently broken by upstream for a Windows-specific use-case.

Apparently some versions of CMake still rely on this archaic feature...

Reported by:	rakuco

MFC 263049:

Garbage collect the old way of adding the libstdc++ include directories
in clang's InitHeaderSearch.cpp.  This has been superseded by David
Chisnall's commit in r255321.

Moreover, if libc++ is used, the libstdc++ include directories should
not be in the search path at all.  These directories are now only used
if you pass -stdlib=libstdc++.

1 files changed, 70 insertions, 75 deletions

diff --git a/contrib/llvm/lib/Analysis/ScalarEvolutionExpander.cpp b/contrib/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
index fcd7ce2..86a557b 100644
--- a/contrib/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/contrib/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -14,6 +14,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Analysis/ScalarEvolutionExpander.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
@@ -176,8 +177,8 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode,
   }
 
   // Save the original insertion point so we can restore it when we're done.
-  BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
-  BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+  DebugLoc Loc = Builder.GetInsertPoint()->getDebugLoc();
+  BuilderType::InsertPointGuard Guard(Builder);
 
   // Move the insertion point out of as many loops as we can.
   while (const Loop *L = SE.LI->getLoopFor(Builder.GetInsertBlock())) {
@@ -191,13 +192,9 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode,
 
   // If we haven't found this binop, insert it.
   Instruction *BO = cast<Instruction>(Builder.CreateBinOp(Opcode, LHS, RHS));
-  BO->setDebugLoc(SaveInsertPt->getDebugLoc());
+  BO->setDebugLoc(Loc);
   rememberInstruction(BO);
 
-  // Restore the original insert point.
-  if (SaveInsertBB)
-    restoreInsertPoint(SaveInsertBB, SaveInsertPt);
-
   return BO;
 }
 
@@ -294,8 +291,8 @@ static bool FactorOutConstant(const SCEV *&S,
     const SCEV *Start = A->getStart();
     if (!FactorOutConstant(Start, Remainder, Factor, SE, TD))
       return false;
-    // FIXME: can use A->getNoWrapFlags(FlagNW)
-    S = SE.getAddRecExpr(Start, Step, A->getLoop(), SCEV::FlagAnyWrap);
+    S = SE.getAddRecExpr(Start, Step, A->getLoop(),
+                         A->getNoWrapFlags(SCEV::FlagNW));
     return true;
   }
 
@@ -348,8 +345,7 @@ static void SplitAddRecs(SmallVectorImpl<const SCEV *> &Ops,
       AddRecs.push_back(SE.getAddRecExpr(Zero,
                                          A->getStepRecurrence(SE),
                                          A->getLoop(),
-                                         // FIXME: A->getNoWrapFlags(FlagNW)
-                                         SCEV::FlagAnyWrap));
+                                         A->getNoWrapFlags(SCEV::FlagNW)));
       if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Start)) {
         Ops[i] = Zero;
         Ops.append(Add->op_begin(), Add->op_end());
@@ -407,6 +403,10 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
   // without the other.
   SplitAddRecs(Ops, Ty, SE);
 
+  Type *IntPtrTy = SE.TD
+                 ? SE.TD->getIntPtrType(PTy)
+                 : Type::getInt64Ty(PTy->getContext());
+
   // Descend down the pointer's type and attempt to convert the other
   // operands into GEP indices, at each level. The first index in a GEP
   // indexes into the array implied by the pointer operand; the rest of
@@ -417,7 +417,7 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
     // array indexing.
     SmallVector<const SCEV *, 8> ScaledOps;
     if (ElTy->isSized()) {
-      const SCEV *ElSize = SE.getSizeOfExpr(ElTy);
+      const SCEV *ElSize = SE.getSizeOfExpr(IntPtrTy, ElTy);
       if (!ElSize->isZero()) {
         SmallVector<const SCEV *, 8> NewOps;
         for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
@@ -549,8 +549,7 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
     }
 
     // Save the original insertion point so we can restore it when we're done.
-    BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
-    BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+    BuilderType::InsertPointGuard Guard(Builder);
 
     // Move the insertion point out of as many loops as we can.
     while (const Loop *L = SE.LI->getLoopFor(Builder.GetInsertBlock())) {
@@ -566,16 +565,11 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
     Value *GEP = Builder.CreateGEP(V, Idx, "uglygep");
     rememberInstruction(GEP);
 
-    // Restore the original insert point.
-    if (SaveInsertBB)
-      restoreInsertPoint(SaveInsertBB, SaveInsertPt);
-
     return GEP;
   }
 
   // Save the original insertion point so we can restore it when we're done.
-  BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
-  BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+  BuilderType::InsertPoint SaveInsertPt = Builder.saveIP();
 
   // Move the insertion point out of as many loops as we can.
   while (const Loop *L = SE.LI->getLoopFor(Builder.GetInsertBlock())) {
@@ -611,8 +605,7 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
   rememberInstruction(GEP);
 
   // Restore the original insert point.
-  if (SaveInsertBB)
-    restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+  Builder.restoreIP(SaveInsertPt);
 
   return expand(SE.getAddExpr(Ops));
 }
@@ -846,8 +839,7 @@ static void ExposePointerBase(const SCEV *&Base, const SCEV *&Rest,
                          SE.getAddRecExpr(SE.getConstant(A->getType(), 0),
                                           A->getStepRecurrence(SE),
                                           A->getLoop(),
-                                          // FIXME: A->getNoWrapFlags(FlagNW)
-                                          SCEV::FlagAnyWrap));
+                                          A->getNoWrapFlags(SCEV::FlagNW)));
   }
   if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(Base)) {
     Base = A->getOperand(A->getNumOperands()-1);
@@ -1078,8 +1070,7 @@ SCEVExpander::getAddRecExprPHILiterally(const SCEVAddRecExpr *Normalized,
   }
 
   // Save the original insertion point so we can restore it when we're done.
-  BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
-  BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+  BuilderType::InsertPointGuard Guard(Builder);
 
   // Another AddRec may need to be recursively expanded below. For example, if
   // this AddRec is quadratic, the StepV may itself be an AddRec in this
@@ -1137,14 +1128,15 @@ SCEVExpander::getAddRecExprPHILiterally(const SCEVAddRecExpr *Normalized,
       IVIncInsertPos : Pred->getTerminator();
     Builder.SetInsertPoint(InsertPos);
     Value *IncV = expandIVInc(PN, StepV, L, ExpandTy, IntTy, useSubtract);
-
+    if (isa<OverflowingBinaryOperator>(IncV)) {
+      if (Normalized->getNoWrapFlags(SCEV::FlagNUW))
+        cast<BinaryOperator>(IncV)->setHasNoUnsignedWrap();
+      if (Normalized->getNoWrapFlags(SCEV::FlagNSW))
+        cast<BinaryOperator>(IncV)->setHasNoSignedWrap();
+    }
     PN->addIncoming(IncV, Pred);
   }
 
-  // Restore the original insert point.
-  if (SaveInsertBB)
-    restoreInsertPoint(SaveInsertBB, SaveInsertPt);
-
   // After expanding subexpressions, restore the PostIncLoops set so the caller
   // can ensure that IVIncrement dominates the current uses.
   PostIncLoops = SavedPostIncLoops;
@@ -1180,8 +1172,7 @@ Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
     Normalized = cast<SCEVAddRecExpr>(
       SE.getAddRecExpr(Start, Normalized->getStepRecurrence(SE),
                        Normalized->getLoop(),
-                       // FIXME: Normalized->getNoWrapFlags(FlagNW)
-                       SCEV::FlagAnyWrap));
+                       Normalized->getNoWrapFlags(SCEV::FlagNW)));
   }
 
   // Strip off any non-loop-dominating component from the addrec step.
@@ -1191,11 +1182,9 @@ Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
     PostLoopScale = Step;
     Step = SE.getConstant(Normalized->getType(), 1);
     Normalized =
-      cast<SCEVAddRecExpr>(SE.getAddRecExpr(Start, Step,
-                                            Normalized->getLoop(),
-                                            // FIXME: Normalized
-                                            // ->getNoWrapFlags(FlagNW)
-                                            SCEV::FlagAnyWrap));
+      cast<SCEVAddRecExpr>(SE.getAddRecExpr(
+                             Start, Step, Normalized->getLoop(),
+                             Normalized->getNoWrapFlags(SCEV::FlagNW)));
   }
 
   // Expand the core addrec. If we need post-loop scaling, force it to
@@ -1232,19 +1221,19 @@ Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
         !ExpandTy->isPointerTy() && Step->isNonConstantNegative();
       if (useSubtract)
         Step = SE.getNegativeSCEV(Step);
-      // Expand the step somewhere that dominates the loop header.
-      BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
-      BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
-      Value *StepV = expandCodeFor(Step, IntTy, L->getHeader()->begin());
-      // Restore the insertion point to the place where the caller has
-      // determined dominates all uses.
-      restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+      Value *StepV;
+      {
+        // Expand the step somewhere that dominates the loop header.
+        BuilderType::InsertPointGuard Guard(Builder);
+        StepV = expandCodeFor(Step, IntTy, L->getHeader()->begin());
+      }
       Result = expandIVInc(PN, StepV, L, ExpandTy, IntTy, useSubtract);
     }
   }
 
   // Re-apply any non-loop-dominating scale.
   if (PostLoopScale) {
+    assert(S->isAffine() && "Can't linearly scale non-affine recurrences.");
     Result = InsertNoopCastOfTo(Result, IntTy);
     Result = Builder.CreateMul(Result,
                                expandCodeFor(PostLoopScale, IntTy));
@@ -1288,18 +1277,15 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
     for (unsigned i = 0, e = S->getNumOperands(); i != e; ++i)
       NewOps[i] = SE.getAnyExtendExpr(S->op_begin()[i], CanonicalIV->getType());
     Value *V = expand(SE.getAddRecExpr(NewOps, S->getLoop(),
-                                       // FIXME: S->getNoWrapFlags(FlagNW)
-                                       SCEV::FlagAnyWrap));
-    BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
-    BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+                                       S->getNoWrapFlags(SCEV::FlagNW)));
     BasicBlock::iterator NewInsertPt =
       llvm::next(BasicBlock::iterator(cast<Instruction>(V)));
+    BuilderType::InsertPointGuard Guard(Builder);
     while (isa<PHINode>(NewInsertPt) || isa<DbgInfoIntrinsic>(NewInsertPt) ||
            isa<LandingPadInst>(NewInsertPt))
       ++NewInsertPt;
     V = expandCodeFor(SE.getTruncateExpr(SE.getUnknown(V), Ty), 0,
                       NewInsertPt);
-    restoreInsertPoint(SaveInsertBB, SaveInsertPt);
     return V;
   }
 
@@ -1307,8 +1293,8 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
   if (!S->getStart()->isZero()) {
     SmallVector<const SCEV *, 4> NewOps(S->op_begin(), S->op_end());
     NewOps[0] = SE.getConstant(Ty, 0);
-    // FIXME: can use S->getNoWrapFlags()
-    const SCEV *Rest = SE.getAddRecExpr(NewOps, L, SCEV::FlagAnyWrap);
+    const SCEV *Rest = SE.getAddRecExpr(NewOps, L,
+                                        S->getNoWrapFlags(SCEV::FlagNW));
 
     // Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
     // comments on expandAddToGEP for details.
@@ -1343,9 +1329,13 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
                                   Header->begin());
     rememberInstruction(CanonicalIV);
 
+    SmallSet<BasicBlock *, 4> PredSeen;
     Constant *One = ConstantInt::get(Ty, 1);
     for (pred_iterator HPI = HPB; HPI != HPE; ++HPI) {
       BasicBlock *HP = *HPI;
+      if (!PredSeen.insert(HP))
+        continue;
+
       if (L->contains(HP)) {
         // Insert a unit add instruction right before the terminator
         // corresponding to the back-edge.
@@ -1528,8 +1518,7 @@ Value *SCEVExpander::expand(const SCEV *S) {
   if (I != InsertedExpressions.end())
     return I->second;
 
-  BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
-  BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+  BuilderType::InsertPointGuard Guard(Builder);
   Builder.SetInsertPoint(InsertPt->getParent(), InsertPt);
 
   // Expand the expression into instructions.
@@ -1542,8 +1531,6 @@ Value *SCEVExpander::expand(const SCEV *S) {
   // a postinc expansion, it could be reused by a non postinc user, but only if
   // its insertion point was already at the head of the loop.
   InsertedExpressions[std::make_pair(S, InsertPt)] = V;
-
-  restoreInsertPoint(SaveInsertBB, SaveInsertPt);
   return V;
 }
 
@@ -1554,10 +1541,6 @@ void SCEVExpander::rememberInstruction(Value *I) {
     InsertedValues.insert(I);
 }
 
-void SCEVExpander::restoreInsertPoint(BasicBlock *BB, BasicBlock::iterator I) {
-  Builder.SetInsertPoint(BB, I);
-}
-
 /// getOrInsertCanonicalInductionVariable - This method returns the
 /// canonical induction variable of the specified type for the specified
 /// loop (inserting one if there is none).  A canonical induction variable
@@ -1573,11 +1556,8 @@ SCEVExpander::getOrInsertCanonicalInductionVariable(const Loop *L,
                                    SE.getConstant(Ty, 1), L, SCEV::FlagAnyWrap);
 
   // Emit code for it.
-  BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
-  BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+  BuilderType::InsertPointGuard Guard(Builder);
   PHINode *V = cast<PHINode>(expandCodeFor(H, 0, L->getHeader()->begin()));
-  if (SaveInsertBB)
-    restoreInsertPoint(SaveInsertBB, SaveInsertPt);
 
   return V;
 }
@@ -1725,28 +1705,43 @@ namespace {
 // Currently, we only allow division by a nonzero constant here. If this is
 // inadequate, we could easily allow division by SCEVUnknown by using
 // ValueTracking to check isKnownNonZero().
+//
+// We cannot generally expand recurrences unless the step dominates the loop
+// header. The expander handles the special case of affine recurrences by
+// scaling the recurrence outside the loop, but this technique isn't generally
+// applicable. Expanding a nested recurrence outside a loop requires computing
+// binomial coefficients. This could be done, but the recurrence has to be in a
+// perfectly reduced form, which can't be guaranteed.
 struct SCEVFindUnsafe {
+  ScalarEvolution &SE;
   bool IsUnsafe;
 
-  SCEVFindUnsafe(): IsUnsafe(false) {}
+  SCEVFindUnsafe(ScalarEvolution &se): SE(se), IsUnsafe(false) {}
 
   bool follow(const SCEV *S) {
-    const SCEVUDivExpr *D = dyn_cast<SCEVUDivExpr>(S);
-    if (!D)
-      return true;
-    const SCEVConstant *SC = dyn_cast<SCEVConstant>(D->getRHS());
-    if (SC && !SC->getValue()->isZero())
-      return true;
-    IsUnsafe = true;
-    return false;
+    if (const SCEVUDivExpr *D = dyn_cast<SCEVUDivExpr>(S)) {
+      const SCEVConstant *SC = dyn_cast<SCEVConstant>(D->getRHS());
+      if (!SC || SC->getValue()->isZero()) {
+        IsUnsafe = true;
+        return false;
+      }
+    }
+    if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
+      const SCEV *Step = AR->getStepRecurrence(SE);
+      if (!AR->isAffine() && !SE.dominates(Step, AR->getLoop()->getHeader())) {
+        IsUnsafe = true;
+        return false;
+      }
+    }
+    return true;
   }
   bool isDone() const { return IsUnsafe; }
 };
 }
 
 namespace llvm {
-bool isSafeToExpand(const SCEV *S) {
-  SCEVFindUnsafe Search;
+bool isSafeToExpand(const SCEV *S, ScalarEvolution &SE) {
+  SCEVFindUnsafe Search(SE);
   visitAll(S, Search);
   return !Search.IsUnsafe;
 }