[llvm-dev] Textual IR value names

Mehdi AMINI via llvm-dev
Fri, 11 Jan 2019 00:06:13 -0000

Having it by default for -S -emit-llvm seems like a good default to me.
Is it enough to make clang's behavior independent of the build settings?

--
Mehdi


On Thu, Jan 10, 2019 at 1:14 PM James Y Knight via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> +1! I didn't realize that you could even change that in a release
build,
> but I concur that it should be enabled by default at least when emitting
> textual asm. The efficiency rationale for having it default off doesn't
> really seem to apply to that case.
>
> On Thu, Jan 10, 2019 at 3:14 PM Cranmer, Joshua via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> While I understand the value of turning it off, it is somewhat annoying
>> when you're trying to run a clang -S -emit-llvm to discover that
you're not
>> getting any value names. I would suggest that, irrespective of the kind
of
>> build you use, -S -emit-llvm should cause the value names to be
defaulted
>> to on as a principle of least surprise to the user.
>>
>> -----Original Message-----
>> From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of
>> David Greene via llvm-dev
>> Sent: Thursday, January 10, 2019 15:05
>> To: Craig Topper <craig.topper at gmail.com>
>> Cc: llvm-dev at lists.llvm.org
>> Subject: Re: [llvm-dev] Textual IR value names
>>
>> Craig Topper via llvm-dev <llvm-dev at lists.llvm.org> writes:
>>
>> > The names are dropped to save memory when a release build of the
>> > compiler is being used. This is what you probably want on a
release
>> > compiler you intend to ship since it should be faster. The NDEBUG
>> > check is an easy way to tell the difference between release and
debug
>> > builds. People probably don't want to have to remember to set
an
>> > additional cmake option to make a release compiler faster.
>>
>> The CMake option could override the current behavior.  Then users
>> wouldn't be forced to remember to set an option to make release
compilers
>> faster.
>>
>> In the end it's not a huge deal, I just found keying off asserts to
be
>> quite surprising and it took some time for me to figure out what was
going
>> on.
>>
>>                             -David
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