[PATCH] D102401: [AMDGPU] Allocate LDS globals in sorted order of their size and alignment.

[Stanislav Mekhanoshin via Phabricator via llvm-commits]

rampitec added inline comments.


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Comment at: llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp:92-93
+
+  // Sort LDS globals (which are used within kernel K) by size, descending, and
+  // then, by alignment, descending. On ties, sort by name, lexicographical.
+  llvm::stable_sort(
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hsmhsm wrote:
> foad wrote:
> > Why is sorting by size important?
> > 
> > I can see that sorting by alignment, descending, avoids alignment gaps (at least in the common case where an object's size is a multiple of its alignment). But sorting by size //first// means that most globals //won't// be sorted by alignment (unless they happened to have the same size and different alignments), so you won't get that benefit.
> I think we need to first sort based on "alignment", then on tie, based on size.
Probably yes. Strategy to sort by size was used along with the super-alignment, so did the same thing.


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  https://reviews.llvm.org/D102401/new/

https://reviews.llvm.org/D102401