Update llvm/clang to trunk r126547.

There are several bugfixes in this update, but the most important one is
to ensure __start_ and __stop_ symbols for linker sets and kernel module
metadata are always emitted in object files:

  http://llvm.org/bugs/show_bug.cgi?id=9292

Before this fix, if you compiled kernel modules with clang, they would
not be properly processed by kldxref, and if they had any dependencies,
the kernel would fail to load those.  Another problem occurred when
attempting to mount a tmpfs filesystem, which would result in 'operation
not supported by device'.

3 files changed, 30 insertions, 30 deletions

diff --git a/contrib/llvm/lib/Transforms/Utils/Local.cpp b/contrib/llvm/lib/Transforms/Utils/Local.cpp
index 063c76e..3f789fa 100644
--- a/contrib/llvm/lib/Transforms/Utils/Local.cpp
+++ b/contrib/llvm/lib/Transforms/Utils/Local.cpp
@@ -262,12 +262,13 @@ bool llvm::RecursivelyDeleteTriviallyDeadInstructions(Value *V) {
 
 /// areAllUsesEqual - Check whether the uses of a value are all the same.
 /// This is similar to Instruction::hasOneUse() except this will also return
-/// true when there are multiple uses that all refer to the same value.
+/// true when there are no uses or multiple uses that all refer to the same
+/// value.
 static bool areAllUsesEqual(Instruction *I) {
   Value::use_iterator UI = I->use_begin();
   Value::use_iterator UE = I->use_end();
   if (UI == UE)
-    return false;
+    return true;
 
   User *TheUse = *UI;
   for (++UI; UI != UE; ++UI) {
@@ -281,31 +282,24 @@ static bool areAllUsesEqual(Instruction *I) {
 /// dead PHI node, due to being a def-use chain of single-use nodes that
 /// either forms a cycle or is terminated by a trivially dead instruction,
 /// delete it.  If that makes any of its operands trivially dead, delete them
-/// too, recursively.  Return true if the PHI node is actually deleted.
+/// too, recursively.  Return true if a change was made.
 bool llvm::RecursivelyDeleteDeadPHINode(PHINode *PN) {
-  // We can remove a PHI if it is on a cycle in the def-use graph
-  // where each node in the cycle has degree one, i.e. only one use,
-  // and is an instruction with no side effects.
-  if (!areAllUsesEqual(PN))
-    return false;
+  SmallPtrSet<Instruction*, 4> Visited;
+  for (Instruction *I = PN; areAllUsesEqual(I) && !I->mayHaveSideEffects();
+       I = cast<Instruction>(*I->use_begin())) {
+    if (I->use_empty())
+      return RecursivelyDeleteTriviallyDeadInstructions(I);
 
-  bool Changed = false;
-  SmallPtrSet<PHINode *, 4> PHIs;
-  PHIs.insert(PN);
-  for (Instruction *J = cast<Instruction>(*PN->use_begin());
-       areAllUsesEqual(J) && !J->mayHaveSideEffects();
-       J = cast<Instruction>(*J->use_begin()))
-    // If we find a PHI more than once, we're on a cycle that
+    // If we find an instruction more than once, we're on a cycle that
     // won't prove fruitful.
-    if (PHINode *JP = dyn_cast<PHINode>(J))
-      if (!PHIs.insert(JP)) {
-        // Break the cycle and delete the PHI and its operands.
-        JP->replaceAllUsesWith(UndefValue::get(JP->getType()));
-        (void)RecursivelyDeleteTriviallyDeadInstructions(JP);
-        Changed = true;
-        break;
-      }
-  return Changed;
+    if (!Visited.insert(I)) {
+      // Break the cycle and delete the instruction and its operands.
+      I->replaceAllUsesWith(UndefValue::get(I->getType()));
+      (void)RecursivelyDeleteTriviallyDeadInstructions(I);
+      return true;
+    }
+  }
+  return false;
 }
 
 /// SimplifyInstructionsInBlock - Scan the specified basic block and try to
diff --git a/contrib/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp b/contrib/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
index e6a4373..7788857 100644
--- a/contrib/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
+++ b/contrib/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
@@ -35,6 +35,7 @@
 #include "llvm/Metadata.h"
 #include "llvm/Analysis/AliasSetTracker.h"
 #include "llvm/Analysis/DebugInfo.h"
+#include "llvm/Analysis/DIBuilder.h"
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/ADT/DenseMap.h"
@@ -190,7 +191,7 @@ namespace {
     ///
     std::vector<AllocaInst*> Allocas;
     DominatorTree &DT;
-    DIFactory *DIF;
+    DIBuilder *DIB;
 
     /// AST - An AliasSetTracker object to update.  If null, don't update it.
     ///
@@ -235,9 +236,9 @@ namespace {
   public:
     PromoteMem2Reg(const std::vector<AllocaInst*> &A, DominatorTree &dt,
                    AliasSetTracker *ast)
-      : Allocas(A), DT(dt), DIF(0), AST(ast) {}
+      : Allocas(A), DT(dt), DIB(0), AST(ast) {}
     ~PromoteMem2Reg() {
-      delete DIF;
+      delete DIB;
     }
 
     void run();
@@ -951,9 +952,9 @@ void PromoteMem2Reg::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
   if (!DIVar.Verify())
     return;
 
-  if (!DIF)
-    DIF = new DIFactory(*SI->getParent()->getParent()->getParent());
-  Instruction *DbgVal = DIF->InsertDbgValueIntrinsic(SI->getOperand(0), 0,
+  if (!DIB)
+    DIB = new DIBuilder(*SI->getParent()->getParent()->getParent());
+  Instruction *DbgVal = DIB->insertDbgValueIntrinsic(SI->getOperand(0), 0,
                                                      DIVar, SI);
   
   // Propagate any debug metadata from the store onto the dbg.value.
diff --git a/contrib/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/contrib/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index fb660db..c670885 100644
--- a/contrib/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/contrib/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -247,6 +247,11 @@ static bool DominatesMergePoint(Value *V, BasicBlock *BB,
     if (PBB->getFirstNonPHIOrDbg() != I)
       return false;
     break;
+  case Instruction::GetElementPtr:
+    // GEPs are cheap if all indices are constant.
+    if (!cast<GetElementPtrInst>(I)->hasAllConstantIndices())
+      return false;
+    break;
   case Instruction::Add:
   case Instruction::Sub:
   case Instruction::And: