From 2b066988909948dc3d53d01760bc2d71d32f3feb Mon Sep 17 00:00:00 2001
From: dim <dim@FreeBSD.org>
Date: Mon, 2 May 2011 19:34:44 +0000
Subject: Vendor import of llvm trunk r130700:
 http://llvm.org/svn/llvm-project/llvm/trunk@130700

---
 lib/Transforms/Scalar/MemCpyOptimizer.cpp | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

(limited to 'lib/Transforms/Scalar/MemCpyOptimizer.cpp')

diff --git a/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index bde0e53..a3035cb 100644
--- a/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/lib/Transforms/Scalar/MemCpyOptimizer.cpp
@@ -28,6 +28,7 @@
 #include "llvm/Support/IRBuilder.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetLibraryInfo.h"
 #include <list>
 using namespace llvm;
 
@@ -299,12 +300,15 @@ void MemsetRanges::addRange(int64_t Start, int64_t Size, Value *Ptr,
 namespace {
   class MemCpyOpt : public FunctionPass {
     MemoryDependenceAnalysis *MD;
+    TargetLibraryInfo *TLI;
     const TargetData *TD;
   public:
     static char ID; // Pass identification, replacement for typeid
     MemCpyOpt() : FunctionPass(ID) {
       initializeMemCpyOptPass(*PassRegistry::getPassRegistry());
       MD = 0;
+      TLI = 0;
+      TD = 0;
     }
 
     bool runOnFunction(Function &F);
@@ -316,6 +320,7 @@ namespace {
       AU.addRequired<DominatorTree>();
       AU.addRequired<MemoryDependenceAnalysis>();
       AU.addRequired<AliasAnalysis>();
+      AU.addRequired<TargetLibraryInfo>();
       AU.addPreserved<AliasAnalysis>();
       AU.addPreserved<MemoryDependenceAnalysis>();
     }
@@ -346,6 +351,7 @@ INITIALIZE_PASS_BEGIN(MemCpyOpt, "memcpyopt", "MemCpy Optimization",
                       false, false)
 INITIALIZE_PASS_DEPENDENCY(DominatorTree)
 INITIALIZE_PASS_DEPENDENCY(MemoryDependenceAnalysis)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
 INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
 INITIALIZE_PASS_END(MemCpyOpt, "memcpyopt", "MemCpy Optimization",
                     false, false)
@@ -688,7 +694,7 @@ bool MemCpyOpt::processMemCpyMemCpyDependence(MemCpyInst *M, MemCpyInst *MDep,
   if (M->getSource() == MDep->getSource())
     return false;
   
-  // Second, the length of the memcpy's must be the same, or the preceeding one
+  // Second, the length of the memcpy's must be the same, or the preceding one
   // must be larger than the following one.
   ConstantInt *MDepLen = dyn_cast<ConstantInt>(MDep->getLength());
   ConstantInt *MLen = dyn_cast<ConstantInt>(M->getLength());
@@ -804,6 +810,9 @@ bool MemCpyOpt::processMemCpy(MemCpyInst *M) {
 bool MemCpyOpt::processMemMove(MemMoveInst *M) {
   AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
 
+  if (!TLI->has(LibFunc::memmove))
+    return false;
+  
   // See if the pointers alias.
   if (!AA.isNoAlias(AA.getLocationForDest(M), AA.getLocationForSource(M)))
     return false;
@@ -935,6 +944,14 @@ bool MemCpyOpt::runOnFunction(Function &F) {
   bool MadeChange = false;
   MD = &getAnalysis<MemoryDependenceAnalysis>();
   TD = getAnalysisIfAvailable<TargetData>();
+  TLI = &getAnalysis<TargetLibraryInfo>();
+  
+  // If we don't have at least memset and memcpy, there is little point of doing
+  // anything here.  These are required by a freestanding implementation, so if
+  // even they are disabled, there is no point in trying hard.
+  if (!TLI->has(LibFunc::memset) || !TLI->has(LibFunc::memcpy))
+    return false;
+  
   while (1) {
     if (!iterateOnFunction(F))
       break;
-- 
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