[PATCH] D142079: [TableGen] Support custom decoders for variable length instructions

[Min-Yih Hsu via Phabricator via llvm-commits]

myhsu added inline comments.


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Comment at: llvm/include/llvm/Target/Target.td:806-807
+/// doesn't matter.
+/// Note that currently we cannot assign different decoders in the same
+/// (instruction) operand.
 def encoder;
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barannikov88 wrote:
> myhsu wrote:
> > 0x59616e wrote:
> > > Under what circumstances will we need different decoders for the same operand ?
> > I figure it's probably rare but for instance, the binary encoding of an operand was separated in two different places so the decoder has to puzzle them back.
> Is it diagnosed somewhere?
I double check with the code and found that it requires some works to report such diagnostics (e.g. print a warning if two different decoders are used on the same operand), which personally I think it's not worth it.


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  https://reviews.llvm.org/D142079/new/

https://reviews.llvm.org/D142079