[PATCH] D48958: [clang][ubsan] Implicit Cast Sanitizer - integer truncation - clang part

[Roman Lebedev via Phabricator via cfe-commits]

lebedev.ri added a comment.

In https://reviews.llvm.org/D48958#1160479, @vsk wrote:

> In https://reviews.llvm.org/D48958#1160435, @lebedev.ri wrote:
>
> > Thank you for taking a look!
> >
> > In https://reviews.llvm.org/D48958#1160381, @vsk wrote:
> >
> > > I have some minor comments but overall I think this is in good shape. It would be great to see some compile-time numbers just to make sure this is tractable. I'm pretty sure -fsanitize=null would fire more often across a codebase than this check, so I don't anticipate a big surprise here.
> >
> >
> > Could you please clarify, which numbers are you looking for, specifically?
> >  The time it takes to build llvm stage2 with `-fsanitize=implicit-cast`?
> >  Or the time it takes to build llvm stage3 with compiler built with `-fsanitize=implicit-cast`?
>
>
> I had in mind measuring the difference between -fsanitize=undefined and -fsanitize=undefined,implicit-cast, with a stage2 compiler. I think that captures the expected use case: existing ubsan users enabling this new check.


FWIW, i'm trying to look into optimizing these new IR patterns right now https://reviews.llvm.org/D49179 https://reviews.llvm.org/D49247.

>> (The numbers won't be too representable, whole stage-1 takes ~40 minutes here...)
> 
> Ah I see, I'll run a few builds and take a stab at it, then.

Yes, please, thank you!


Repository:
  rC Clang

https://reviews.llvm.org/D48958