[llvm-dev] [X86] Memory folding tables in x86 backend

Joerg Sonnenberger via llvm-dev llvm-dev at lists.llvm.org
Sun Jul 23 04:19:02 PDT 2017

On Sun, Jul 23, 2017 at 08:48:00AM +0000, Musa, Ayman via llvm-dev wrote:
> 3-     Give up on the auto-generation idea and manually update the current tables iteratively with new chunks of instructions until full state is achieved.
> P.s. The TableGen backend emits more than 5200 entries, while the known exception at this point are ~20.

Why can't you do a variation of this by tagging the instructions with a
flag? I.e. for the rm variant, add a flag that says "this has an
equivalent register operand version". Given that a lot of the instruction
patterns are created via multi-classes, I would expect that to require a
lot less than 5200 updates.


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