Re: Put optimization/7871 patches on gcc 3.3 and 3.4 branches

[Gabriel Dos Reis <gdr at integrable-solutions dot net>]

Mark Mitchell <mark@codesourcery.com> writes:

| Ian Lance Taylor wrote:
| 
| > Mark Mitchell <mark@codesourcery.com> writes:
| >
| >>Ian Lance Taylor wrote:
| >>
| >>
| >>>I propose putting the patch for optimization/7871 onto the 3.3 and 3.4
| >>>branches.  I've confirmed that the x86 and m68k test cases in that PR
| >>>are currently broken on both branches, and that this patch fixes those
| >>>test cases on both branches.  I believe that this patch is reasonably
| >>>safe, as it only affects global register variables.
| >>
| >>What is the difference in semantics between SET and CLOBBER in this
| >>context?  Why does your patch help?
| > That part of the patch is Eric's.  It helps because CLOBBER causes a
| > REG_DEAD note to be put on the CALL insn, which is not correct for a
| > global register variable.  The value is not clobbered.  However, it is
| > not safe to assume that the register has the same value after the
| > call.
| 
| OK, that make sense.
| 
| The patch is OK for the mainline and the branch.

And gcc-3_3-branch too.

-- gaby