Make getModRefInfo(Instruction *) not crash on certain types of instructions

[oota-llvm.git] / lib / Analysis / AliasAnalysis.cpp

diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp
index fb162d2699a3b4a150ddb4e1cb22e86795322131..1ee60ff1a307aa7a312193252450a377f1922558 100644 (file)
--- a/lib/Analysis/AliasAnalysis.cpp
+++ b/lib/Analysis/AliasAnalysis.cpp
@@ -82,6 +82,23 @@ void AliasAnalysis::addEscapingUse(Use &U) {
   AA->addEscapingUse(U);
 }
 
+AliasAnalysis::ModRefResult
+AliasAnalysis::getModRefInfo(Instruction *I, ImmutableCallSite Call) {
+  // We may have two calls
+  if (auto CS = ImmutableCallSite(I)) {
+    // Check if the two calls modify the same memory
+    return getModRefInfo(Call, CS);
+  } else {
+    // Otherwise, check if the call modifies or references the
+    // location this memory access defines.  The best we can say
+    // is that if the call references what this instruction
+    // defines, it must be clobbered by this location.
+    const AliasAnalysis::Location DefLoc = AA->getLocation(I);
+    if (getModRefInfo(Call, DefLoc) != AliasAnalysis::NoModRef)
+      return AliasAnalysis::ModRef;
+  }
+  return AliasAnalysis::NoModRef;
+}
 
 AliasAnalysis::ModRefResult
 AliasAnalysis::getModRefInfo(ImmutableCallSite CS,
@@ -330,7 +347,7 @@ AliasAnalysis::getModRefInfo(const LoadInst *L, const Location &Loc) {
 
   // If the load address doesn't alias the given address, it doesn't read
   // or write the specified memory.
-  if (!alias(getLocation(L), Loc))
+  if (Loc.Ptr && !alias(getLocation(L), Loc))
     return NoModRef;
 
   // Otherwise, a load just reads.
@@ -343,15 +360,18 @@ AliasAnalysis::getModRefInfo(const StoreInst *S, const Location &Loc) {
   if (!S->isUnordered())
     return ModRef;
 
-  // If the store address cannot alias the pointer in question, then the
-  // specified memory cannot be modified by the store.
-  if (!alias(getLocation(S), Loc))
-    return NoModRef;
+  if (Loc.Ptr) {
+    // If the store address cannot alias the pointer in question, then the
+    // specified memory cannot be modified by the store.
+    if (!alias(getLocation(S), Loc))
+      return NoModRef;
 
-  // If the pointer is a pointer to constant memory, then it could not have been
-  // modified by this store.
-  if (pointsToConstantMemory(Loc))
-    return NoModRef;
+    // If the pointer is a pointer to constant memory, then it could not have
+    // been modified by this store.
+    if (pointsToConstantMemory(Loc))
+      return NoModRef;
+
+  }
 
   // Otherwise, a store just writes.
   return Mod;
@@ -359,15 +379,18 @@ AliasAnalysis::getModRefInfo(const StoreInst *S, const Location &Loc) {
 
 AliasAnalysis::ModRefResult
 AliasAnalysis::getModRefInfo(const VAArgInst *V, const Location &Loc) {
-  // If the va_arg address cannot alias the pointer in question, then the
-  // specified memory cannot be accessed by the va_arg.
-  if (!alias(getLocation(V), Loc))
-    return NoModRef;
 
-  // If the pointer is a pointer to constant memory, then it could not have been
-  // modified by this va_arg.
-  if (pointsToConstantMemory(Loc))
-    return NoModRef;
+  if (Loc.Ptr) {
+    // If the va_arg address cannot alias the pointer in question, then the
+    // specified memory cannot be accessed by the va_arg.
+    if (!alias(getLocation(V), Loc))
+      return NoModRef;
+
+    // If the pointer is a pointer to constant memory, then it could not have
+    // been modified by this va_arg.
+    if (pointsToConstantMemory(Loc))
+      return NoModRef;
+  }
 
   // Otherwise, a va_arg reads and writes.
   return ModRef;
@@ -380,7 +403,7 @@ AliasAnalysis::getModRefInfo(const AtomicCmpXchgInst *CX, const Location &Loc) {
     return ModRef;
 
   // If the cmpxchg address does not alias the location, it does not access it.
-  if (!alias(getLocation(CX), Loc))
+  if (Loc.Ptr && !alias(getLocation(CX), Loc))
     return NoModRef;
 
   return ModRef;
@@ -393,7 +416,7 @@ AliasAnalysis::getModRefInfo(const AtomicRMWInst *RMW, const Location &Loc) {
     return ModRef;
 
   // If the atomicrmw address does not alias the location, it does not access it.
-  if (!alias(getLocation(RMW), Loc))
+  if (Loc.Ptr && !alias(getLocation(RMW), Loc))
     return NoModRef;
 
   return ModRef;
@@ -407,9 +430,10 @@ AliasAnalysis::ModRefResult
 AliasAnalysis::callCapturesBefore(const Instruction *I,
                                   const AliasAnalysis::Location &MemLoc,
                                   DominatorTree *DT) {
-  if (!DT || !DL) return AliasAnalysis::ModRef;
+  if (!DT)
+    return AliasAnalysis::ModRef;
 
-  const Value *Object = GetUnderlyingObject(MemLoc.Ptr, DL);
+  const Value *Object = GetUnderlyingObject(MemLoc.Ptr, *DL);
   if (!isIdentifiedObject(Object) || isa<GlobalValue>(Object) ||
       isa<Constant>(Object))
     return AliasAnalysis::ModRef;