[PATCH] D46540: [X86] ptwrite intrinsic

[Jonas Hahnfeld via Phabricator via cfe-commits]

Hahnfeld added a comment.

In https://reviews.llvm.org/D46540#1092620, @GBuella wrote:

> In https://reviews.llvm.org/D46540#1091625, @Hahnfeld wrote:
>
> > Could you maybe add some short summaries to your patches? It's hard for non-Intel employees to guess what all these instructions do...
>
>
> Well, I was thinking I could copy-paste this from https://software.intel.com/en-us/articles/intel-sdm :
>  "This instruction reads data in the source operand and sends it to the Intel Processor Trace hardware to be encoded
>  in a PTW packet if TriggerEn, ContextEn, FilterEn, and PTWEn are all set to 1. For more details on these values, see
>  Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 3C, Section 35.2.2, “Software Trace
>  Instrumentation with PTWRITE”."
>
> Do you think this would really help anyone? It appears to be just meaningless without larger context.
>  Those who ever need this, need to read a lot of these manuals anyways, I think noone in practice is going to be enlightened by such a short description.
>
> That of course makes a lot more sense with simpler instructions, e.g. movdir64b - I can just describe that as something like "atomically moving 64 bytes".


My 2 cents: I actually think this is worth a bit because it gives additional information so the reader can at least put the instruction into a category.


Repository:
  rC Clang

https://reviews.llvm.org/D46540