[Bug middle-end/49519] [4.7 Regression] Revision 175272 miscompiled 447.dealII in SPEC CPU 2006

[rguenther at suse dot de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49519

--- Comment #29 from rguenther at suse dot de <rguenther at suse dot de> 2011-07-12 08:35:18 UTC ---
On Tue, 12 Jul 2011, ian at airs dot com wrote:

> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49519
> 
> Ian Lance Taylor <ian at airs dot com> changed:
> 
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                  CC|                            |ian at airs dot com
> 
> --- Comment #27 from Ian Lance Taylor <ian at airs dot com> 2011-07-12 04:37:01 UTC ---
> This patch seems too conservative and it appears that it will cause the
> compiler to miss all tailcalls with pointer arguments.  It only matters if the
> register points to the incoming parameters, which can only  happen in unusual
> cases.  We should be able to determine that reliably.  Janis, did you open a PR
> for the missing optimization?  I didn't see one.

The point is, of course, we have to determine it conservatively correct.
The patch makes sure we do that.

Richard.