[llvm-dev] Global ISel match table

Paul C. Anagnostopoulos via llvm-dev llvm-dev at lists.llvm.org
Sat Dec 12 08:34:49 PST 2020


The Global ISel match table is a sequence of 64-bit entries. For the AMDGPU, there are about 261,000 entries. for the PowerPC, about 32,000. 

A significant amount of memory could be saved by reducing the entries to 32 bits. This would require reworking the matcher to deal with 32-bit entries, and then re-reworking some of the entries to pick up and assemble two 32-bit entries into one 64-bit integer. 

I won't be surprised if there are compelling reasons to keep the entries at 64 bits. I'd like to hear those reasons.



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