[PATCH] D133863: [RISCV] Add MC support of RISCV zcmt Extension

[Xinlong Wu via Phabricator via llvm-commits]

VincentWu added inline comments.


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Comment at: llvm/lib/Target/RISCV/RISCV.td:366
+                       "'Zcmt' (table jump instuctions for code-size reduction)", 
+                       [FeatureExtZca]>; // TODO: add Zicsr as another dependence
+def HasStdExtZcmt : Predicate<"Subtarget->hasStdExtZcmt() && !Subtarget->hasStdExtC()">,
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jrtc27 wrote:
> This is an odd implication, Zcmt works just fine without Zca?
the [[ https://github.com/riscv/riscv-code-size-reduction/releases/tag/v1.0.0-RC5.7 | spec ]] says:
> The Zcmt extension depends on the Zca and Zicsr extensions.

I think maybe `zcmt` needs to be aligned using `c.nop`?  That might be one of the reasons why `zcmt` required `zca`.


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  https://reviews.llvm.org/D133863/new/

https://reviews.llvm.org/D133863