[PATCH] D16227: Make context-sensitive isDereferenceable queries in isSafeToLoadUnconditionally

[Artur Pilipenko via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL260520: Make context-sensitive isDereferenceable queries in isSafeToLoadUnconditionally (authored by apilipenko).

Changed prior to commit:
  http://reviews.llvm.org/D16227?vs=45001&id=47632#toc

Repository:
  rL LLVM

http://reviews.llvm.org/D16227

Files:
  llvm/trunk/include/llvm/Analysis/Loads.h
  llvm/trunk/lib/Analysis/Loads.cpp

Index: llvm/trunk/lib/Analysis/Loads.cpp
===================================================================
--- llvm/trunk/lib/Analysis/Loads.cpp
+++ llvm/trunk/lib/Analysis/Loads.cpp
@@ -56,22 +56,28 @@
 
 /// \brief Check if executing a load of this pointer value cannot trap.
 ///
+/// If DT is specified this method performs context-sensitive analysis.
+///
 /// If it is not obviously safe to load from the specified pointer, we do
 /// a quick local scan of the basic block containing \c ScanFrom, to determine
 /// if the address is already accessed.
 ///
 /// This uses the pointee type to determine how many bytes need to be safe to
 /// load from the pointer.
 bool llvm::isSafeToLoadUnconditionally(Value *V, unsigned Align,
-                                       Instruction *ScanFrom) {
+                                       Instruction *ScanFrom,
+                                       const DominatorTree *DT,
+                                       const TargetLibraryInfo *TLI) {
   const DataLayout &DL = ScanFrom->getModule()->getDataLayout();
 
   // Zero alignment means that the load has the ABI alignment for the target
   if (Align == 0)
     Align = DL.getABITypeAlignment(V->getType()->getPointerElementType());
   assert(isPowerOf2_32(Align));
 
-  if (isDereferenceableAndAlignedPointer(V, Align, DL))
+  // If DT is not specified we can't make context-sensitive query
+  const Instruction* CtxI = DT ? ScanFrom : nullptr;
+  if (isDereferenceableAndAlignedPointer(V, Align, DL, CtxI, DT, TLI))
     return true;
 
   int64_t ByteOffset = 0;
Index: llvm/trunk/include/llvm/Analysis/Loads.h
===================================================================
--- llvm/trunk/include/llvm/Analysis/Loads.h
+++ llvm/trunk/include/llvm/Analysis/Loads.h
@@ -24,11 +24,17 @@
 class MDNode;
 
 /// isSafeToLoadUnconditionally - Return true if we know that executing a load
-/// from this value cannot trap.  If it is not obviously safe to load from the
-/// specified pointer, we do a quick local scan of the basic block containing
-/// ScanFrom, to determine if the address is already accessed.
+/// from this value cannot trap.
+///
+/// If DT is specified this method performs context-sensitive analysis.
+///
+/// If it is not obviously safe to load from the specified pointer, we do a
+/// quick local scan of the basic block containing ScanFrom, to determine if
+/// the address is already accessed.
 bool isSafeToLoadUnconditionally(Value *V, unsigned Align,
-                                 Instruction *ScanFrom);
+                                 Instruction *ScanFrom,
+                                 const DominatorTree *DT = nullptr,
+                                 const TargetLibraryInfo *TLI = nullptr);
 
 /// DefMaxInstsToScan - the default number of maximum instructions
 /// to scan in the block, used by FindAvailableLoadedValue().


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