[llvm] [Offload] Guard HSA implicit arguments if they aren't created (PR #133073)

[Matt Arsenault via llvm-commits]

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@@ -3386,16 +3386,18 @@ Error AMDGPUKernelTy::launchImpl(GenericDeviceTy &GenericDevice,
     return Err;
 
   // Set the COV5+ implicit arguments to the appropriate values.
-  ImplArgs->BlockCountX = NumBlocks[0];
-  ImplArgs->BlockCountY = NumBlocks[1];
-  ImplArgs->BlockCountZ = NumBlocks[2];
-  ImplArgs->GroupSizeX = NumThreads[0];
-  ImplArgs->GroupSizeY = NumThreads[1];
-  ImplArgs->GroupSizeZ = NumThreads[2];
-  ImplArgs->GridDims = NumBlocks[2] * NumThreads[2] > 1
-                           ? 3
-                           : 1 + (NumBlocks[1] * NumThreads[1] != 1);
-  ImplArgs->DynamicLdsSize = KernelArgs.DynCGroupMem;
+  if (ImplArgs) {
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arsenm wrote:

Can you sink the argument initialization above down here, below the getStream stuff? This is a weird logical split 

https://github.com/llvm/llvm-project/pull/133073