[BasicAliasAnalysis] Do not check ModRef table for intrinsics

[igor-laevsky]

Summary

All possible ModRef behaviours can be completely represented using existing LLVM IR attributes. And since http://reviews.llvm.org/D11352 this attributes are emitted for intrinsics. There is no need to use separate ModRef table in the BasicAliasAnalysis.

This is step towards removal of the GET_INTRINSIC_MODREF_BEHAVIOR table.

[hfinkel]

LGTM.

llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp

 /// Returns the behavior when calling the given function. For use when the call
 /// site is not known.
 FunctionModRefBehavior
 BasicAliasAnalysis::getModRefBehavior(const Function *F) {
   // If the function declares it doesn't access memory, we can't do better.
   if (F->doesNotAccessMemory())
     return FMRB_DoesNotAccessMemory;
 
-  // For intrinsics, we can check the table.
-  if (Intrinsic::ID iid = F->getIntrinsicID()) {
-#define GET_INTRINSIC_MODREF_BEHAVIOR
-#include "llvm/IR/Intrinsics.gen"
-#undef GET_INTRINSIC_MODREF_BEHAVIOR
-  }
-
   FunctionModRefBehavior Min = FMRB_UnknownModRefBehavior;
 
   // If the function declares it only reads memory, go with that.
   if (F->onlyReadsMemory())
     Min = FMRB_OnlyReadsMemory;
 
   if (F->onlyAccessesArgMemory())
     Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesArgumentPointees);