Fix a build warning of unhandled enum in switch

[weimingz]

Summary

LLVM adds a new value FMRB_DoesNotReadMemory in the enumeration.

[weimingz]

Please check if the case is handled correctly.

[grosser]

Hi Johannes,

this is code you added. Would you like to have a look at this patch?

[Meinersbur]

If I understand FMRB_DoesNotReadMemory correctly, it can write to memory anywhere. It should be handled pessimistically, i.e. reject a region containing it as its sideeffects are not predictable (return false;).

[weimingz]

right, it's write-only attribute.

[jdoerfert]

LGTM, thanks for the patch.

polly/trunk/lib/Analysis/ScopBuilder.cpp

bool ScopBuilder::buildAccessCallInst(MemAccInst Inst, Loop *L) {
   bool ReadOnly = false;
   auto *AF = SE.getConstant(IntegerType::getInt64Ty(CI->getContext()), 0);
   auto *CalledFunction = CI->getCalledFunction();
   switch (AA.getModRefBehavior(CalledFunction)) {
   case llvm::FMRB_UnknownModRefBehavior:
     llvm_unreachable("Unknown mod ref behaviour cannot be represented.");
   case llvm::FMRB_DoesNotAccessMemory:
     return true;
+  case llvm::FMRB_DoesNotReadMemory:
+    return false;
   case llvm::FMRB_OnlyReadsMemory:
     GlobalReads.push_back(CI);
     return true;
   case llvm::FMRB_OnlyReadsArgumentPointees:
     ReadOnly = true;
   // Fall through
   case llvm::FMRB_OnlyAccessesArgumentPointees:
     auto AccType = ReadOnly ? MemoryAccess::READ : MemoryAccess::MAY_WRITE;

polly/trunk/lib/Analysis/ScopDetection.cpp

case llvm::FMRB_OnlyAccessesArgumentPointees:
 
         // Implicitly disable delinearization since we have an unknown
         // accesses with an unknown access function.
         Context.HasUnknownAccess = true;
       }
 
       Context.AST.add(&CI);
       return true;
+    case FMRB_DoesNotReadMemory:
+      return false;
     }
   }
 
   return false;
 }
 
 bool ScopDetection::isValidIntrinsicInst(IntrinsicInst &II,
                                          DetectionContext &Context) const {