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Re: [PATCH 3/3] Extend -falign-FOO=N to N[:M[:N2[:M2]]]


On 06/29/2018 09:04 PM, Jeff Law wrote:
> I think this is fine for the trunk.
> 
> jeff

Thank you Jeff.

I found some issues when doing build of all targets (contrib/config-list.mk).
I'll update patch and test that affected cross-compilers still produce same output.

However I noticed one ppc64 issue:

$ cat -n gcc/config/powerpcspe/powerpcspe.c

  5401        /* Set branch target alignment, if not optimizing for size.  */
  5402        if (!optimize_size)
  5403          {
  5404            /* Cell wants to be aligned 8byte for dual issue.  Titan wants to be
  5405               aligned 8byte to avoid misprediction by the branch predictor.  */
  5406            if (rs6000_cpu == PROCESSOR_TITAN
  5407                || rs6000_cpu == PROCESSOR_CELL)
  5408              {
  5409                if (align_functions <= 0)
  5410                  align_functions = 8;
  5411                if (align_jumps <= 0)
  5412                  align_jumps = 8;
  5413                if (align_loops <= 0)
  5414                  align_loops = 8;
  5415              }
  5416            if (rs6000_align_branch_targets)
  5417              {
  5418                if (align_functions <= 0)
  5419                  align_functions = 16;
  5420                if (align_jumps <= 0)
  5421                  align_jumps = 16;
  5422                if (align_loops <= 0)
  5423                  {
  5424                    can_override_loop_align = 1;
  5425                    align_loops = 16;
  5426                  }
  5427              }
  5428            if (align_jumps_max_skip <= 0)
  5429              align_jumps_max_skip = 15;
  5430            if (align_loops_max_skip <= 0)
  5431              align_loops_max_skip = 15;

Note that at line 5429 there's set of align_jumps_max_skip to 15 if not set by default.
At line 5412 align_jumps is set to 8, and align_jumps_max_skip should be equal align_jumps - 1.
That's a discrepancy. Segher can you please take a look?

Thanks,
Martin


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