Re: Fix reload1.c warning for some targets

[Jeff Law <law@redhat.com>]

On 09/03/2015 02:39 AM, Richard Sandiford wrote:
>
> It sounds like Jeff has a much more radical rewrite in mind,
Certainly not anything on the immediate horizon.  The amount of block 
copying that'd be needed to isolate the jump threading path would be 
significant.

I do wonder if we should be looking at a way to mark paths which have 
jump threading opportunities, but which we do not optimize and exploit 
that information in the uninit and other analysis.

Bodik had a paper on those concepts as well.  He was mostly looking at 
how to account for those paths in code coverage analysis, but there may 
be something useful in there.

> so for now how about just turning -Wmaybe-uninitialized into
> a warning for this function?  The patch will mean that it becomes
> a warning even if someone turns off warnings on the command line,
> but I don't think that's important.
>
> Bootstrapped and regression-tested on x86_64-linux-gnu.  Also tested
> with a cross-compiler to sparc-linux-gnu (which also triggered the
> warning for me).  Tested that clang could still compile the file.
> OK to install?
>
>
> gcc/
> 	* reload1.c (elimination_costs_in_insn): Locally turn
> 	-Wmaybe-uninitialized into a warning.
I can live with this.  Though I'd appreciate it if someone could reduce 
the sparcv9 testcase and create a bug to track it too.

jeff