AMDGPU: Report AMDGPUPromoteAlloca changed the function

[• tstellarAMD]

LGTM.

[arsenm]

r259547

lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp

bool AMDGPUPromoteAlloca::doInitialization(Module &M) {
 
   return false;
 }
 
 bool AMDGPUPromoteAlloca::runOnFunction(Function &F) {
   if (!TM)
     return false;
 
-  const AMDGPUSubtarget &ST = TM->getSubtarget<AMDGPUSubtarget>(F);
-
   FunctionType *FTy = F.getFunctionType();
-  LocalMemAvailable = ST.getLocalMemorySize();
-
 
   // If the function has any arguments in the local address space, then it's
   // possible these arguments require the entire local memory space, so
   // we cannot use local memory in the pass.
   for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
     Type *ParamTy = FTy->getParamType(i);
     if (ParamTy->isPointerTy() &&
         ParamTy->getPointerAddressSpace() == AMDGPUAS::LOCAL_ADDRESS) {
-      LocalMemAvailable = 0;
       DEBUG(dbgs() << "Function has local memory argument.  Promoting to "
                       "local memory disabled.\n");
-      break;
+      return false;
     }
   }
 
-  if (LocalMemAvailable > 0) {
-    // Check how much local memory is being used by global objects
-    for (Module::global_iterator I = Mod->global_begin(),
-                                 E = Mod->global_end(); I != E; ++I) {
-      GlobalVariable *GV = &*I;
-      if (GV->getType()->getAddressSpace() != AMDGPUAS::LOCAL_ADDRESS)
-        continue;
-      for (Value::use_iterator U = GV->use_begin(),
-                               UE = GV->use_end(); U != UE; ++U) {
-        Instruction *Use = dyn_cast<Instruction>(*U);
-        if (!Use)
-          continue;
-        if (Use->getParent()->getParent() == &F)
-          LocalMemAvailable -=
-              Mod->getDataLayout().getTypeAllocSize(GV->getValueType());
-      }
-    }
-  }
+  const AMDGPUSubtarget &ST = TM->getSubtarget<AMDGPUSubtarget>(F);
+  LocalMemAvailable = ST.getLocalMemorySize();
+  if (LocalMemAvailable == 0)
+    return false;
+
+
 
   LocalMemAvailable = std::max(0, LocalMemAvailable);
   DEBUG(dbgs() << LocalMemAvailable << "bytes free in local memory.\n");
 
   visit(F);
 
-  return false;
+  return true;
 }
 
 std::pair<Value *, Value *>
 AMDGPUPromoteAlloca::getLocalSizeYZ(IRBuilder<> &Builder) {
   if (!IsAMDHSA) {
     Function *LocalSizeYFn
       = Intrinsic::getDeclaration(Mod, Intrinsic::r600_read_local_size_y);
     Function *LocalSizeZFn