On Mon, 25 May 2015, Dharmakan Rohit Arul Raj wrote: > > -----Original Message----- > > From: Richard Biener [mailto:rguent...@suse.de] > > Sent: Monday, May 18, 2015 1:06 PM > > To: Jeff Law > > Cc: Dharmakan Rohit-B30502; gcc-patches@gcc.gnu.org; Jakub Jelinek; Alan > > Modra; David Edelsohn; Wienskoski Edmar-RA8797 > > Subject: Re: [RFC: Patch, PR 60158] gcc/varasm.c : Pass actual alignment > > value > > to output_constant_pool_2 > > > > On Fri, 15 May 2015, Jeff Law wrote: > > > > > On 05/15/2015 04:37 AM, Dharmakan Rohit Arul Raj wrote: > > > > > > > > > -----Original Message----- > > > > > From: Jeff Law [mailto:l...@redhat.com] > > > > > Sent: Friday, May 15, 2015 10:30 AM > > > > > > Just to summarize: By default in GCC v4.7.x, all the constants > > > > > > are put into '.rodata.str1.4' section. In GCC v4.8.x from > > > > > > r192719 onwards, one of the move instruction of the string > > > > > > constant ".LC0" is getting spilled. The reload pass, for any > > > > > > constants that aren't allowed and can't be reloaded in to > > > > > > registers tries to change them into memory references. Then > > > > > > while emitting that string constant to asm code > > > > > > (A:varasm.c: output_constant_pool_1), it explicitly passes the > > > > > > alignment as 1 which prevents the generation of fix-up table > > > > > > entries in 'B: rs6000.c:rs6000_assemble_integer' because the > > > > > > data is considered unaligned now. > > > > > > > > > > > > The bug seems to have gone latent with an unrelated trunk commit > > > > > > r204695 [* tree-ssa-loop-ivopts.c (force_expr_to_var_cost): > > > > > > Refactor the code. Handle type conversion.]. This commit chooses > > > > > > different spill candidates hence all the string constants are > > > > > > being put in to '.rodata.str1.4´section. > > > > > > > > > > > > The check I had in the test case is that if there is a > > > > > > '.data.rel.ro.local', then there should be '.fixup' section > > > > > > generated. > > > > > > > > > > > > Please let me know if you need any other details. > > > > > Thanks. Even though I wasn't able to trigger the bug with the > > > > > testcase from 65018, I went ahead and committed this patch to the > > > > > trunk. It can't hurt and it's the right thing to do. > > > > > > > > > > Thanks for your patience, > > > > > > > > > > > > > Jeff, Thanks for checking-in the changes. > > > > Can we apply the patch to GCC v4.8 and GCC v4.9 branch as well? > > > That's up to the branch maintainers. I'd think it's safe, but it's > > > ultimately their call. > > > > If it's a regression or a wrong-code issue then it's ok to backport given > > the > > patch is safe, of course. > > Just to confirm, can we backport the patch to GCC v4.8 & GCC v4.9 branch?
I've already said what I had to say. I didn't look at the patch. Richard.
