[HIP][AMDGPU] Do not perform Promote Alloca optimization for GPU kernels with dynamic LDS usage.

[kpyzhov]

Summary

The "Promote Alloca" optimization tries to move some stack allocations to statically allocated LDS, so it adds new static LDS loads/stores to the kernel.
Mixed static/dynamic LDS is not correctly supported by the hip-clang yet, so adding static LDS load/stores to a kernel that already has dynamic LDS operations causes conflicts.
This patch disables Promote Alloca optimization for kernels that use dynamic LDS.

[arsenm]

Needs testcase

llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp

740

I think this needs more clarification, since this does handle dynamic LDS as OpenCL uses it through a kernel argument.

[arsenm]

inverse ping

[arsenm]

This can be abandoned, we now handle this

llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp

if (GV.getAddressSpace() != AMDGPUAS::LOCAL_ADDRESS)
       continue;
 
     for (const User *U : GV.users()) {
       const Instruction *Use = dyn_cast<Instruction>(U);
       if (!Use)
         continue;
 
       if (Use->getParent()->getParent() == &F) {
+        // Do not promote alloca to static LDS if this function uses any dynamic shared memory
+        // since mixed static/dynamic LDS is not fully supported yet.
+        uint64_t AllocSize = DL.getTypeAllocSize(GV.getValueType());
+        if (AllocSize == 0)
+          return false;
+
         unsigned Align = GV.getAlignment();
         if (Align == 0)
           Align = DL.getABITypeAlignment(GV.getValueType());
 
         // FIXME: Try to account for padding here. The padding is currently
         // determined from the inverse order of uses in the function. I'm not
         // sure if the use list order is in any way connected to this, so the
         // total reported size is likely incorrect.
-        uint64_t AllocSize = DL.getTypeAllocSize(GV.getValueType());
         CurrentLocalMemUsage = alignTo(CurrentLocalMemUsage, Align);
         CurrentLocalMemUsage += AllocSize;
         break;
       }
     }
   }
 
   unsigned MaxOccupancy = ST.getOccupancyWithLocalMemSize(CurrentLocalMemUsage,