Adding log files to gcc dump and adding testcase-rtl

[David Malcolm]

On Wed, 2022-05-25 at 06:44 -0400, David Malcolm wrote:
> On Wed, 2022-05-25 at 10:25 +0530, RICHU NORMAN wrote:
> > Hi,
> > I am a beginner in gcc. I am trying to add an instruction to riscv-
> > gcc.It
> > would be helpful could help with a few tips .
> 
> Hi Richu - welcome to GCC development.
> 
> FWIW I've written a guide for new GCC contributors which you might find
> helpful:
>   https://gcc-newbies-guide.readthedocs.io/en/latest/index.html
> 
> Caveat: I'm much more familiar with the frontends/diagnostics, rather
> than the backends/RTL, so there may be a "frontend" bias in that guide.
>  
> > 1.How to write comments to rtl or create a custom log file to log
> > comments
> > to rtl dump?
> > 2.How to run testsuite ?
> > 3.Is there a way to directly run an rtl test case? Like giving rtl
> > input
> > and checking the generated asm.(Like in the attachment which is
> > posted in
> > bugzilla[ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82815 ])
> > Please suggest a way to run the gcc-testsuite with these cases. Pfa
> 
> I wrote some notes on dealing with the testsuite, and on running
> individual cases here:
> https://gcc-newbies-guide.readthedocs.io/en/latest/working-with-the-testsuite.html

Looks like that bug relates to a bug in the __RTL reading code (which I
wrote; sorry!).  There are some notes on running cc1 under the debugger
in my guide here:
  https://gcc-newbies-guide.readthedocs.io/en/latest/debugging.html
which should let you put a breakpoint on the relevant code and step
through it.

Some note on __RTL testcases: you will generally want to have a
"startswith" clause on the __RTL to indicate which compilation pass the
RTL was saved at, since RTL goes through several stages in the backend.

"git grep __RTL" should show some examples of existing __RTL-based
testcases.

See also:
  https://gcc.gnu.org/onlinedocs/gccint/RTL-Tests.html

Dave