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Re: [PATCH][IRA] Analysis of register usage of functions for usage by IRA.


On 14/03/13 16:11, Vladimir Makarov wrote:
> On 03/14/2013 05:34 AM, Tom de Vries wrote:
>> On 13/02/13 23:35, Vladimir Makarov wrote:
>>
> Actually, I am done with it.  In general, it is ok.  Although I have 
> some minors comments:
> 

Vladimir,

Thanks for the review.

I split the patch up into 10 patches, to facilitate further review:
...
0001-Add-command-line-option.patch
0002-Add-new-reg-note-REG_CALL_DECL.patch
0003-Add-implicit-parameter-to-find_all_hard_reg_sets.patch
0004-Add-TARGET_FN_OTHER_HARD_REG_USAGE-hook.patch
0005-Implement-TARGET_FN_OTHER_HARD_REG_USAGE-hook-for-ARM.patch
0006-Collect-register-usage-information.patch
0007-Use-collected-register-usage-information.patch
0008-Enable-by-default-at-O2-and-higher.patch
0009-Add-documentation.patch
0010-Add-test-case.patch
...
I'll post these in reply to this email.

> In Changelog, you missed '*" before cgraph.h:
> 
>      * haifa-sched.c (recompute_todo_spec, check_clobbered_conditions): Add
>      new argument to find_all_hard_reg_sets call.
>      cgraph.h (struct cgraph_node): Add function_used_regs,
>      function_used_regs_initialized and function_used_regs_valid fields.
> 

Fixed (in the log of 0006-Collect-register-usage-information.patch).

> 
> @@ -3391,6 +3394,7 @@ df_get_call_refs (struct df_collection_r
>           }
>       }
>         else if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i)
> 
> I'd remove the test of regs_invalidated_by_call.
> 
> +           && TEST_HARD_REG_BIT (fn_reg_set_usage, i)
>              /* no clobbers for regs that are the result of the call */
>              && !TEST_HARD_REG_BIT (defs_generated, i)
> 

Fixed (in 0007-Use-collected-register-usage-information.patch).

> +static void
> +collect_fn_hard_reg_usage (void)
> +{
> +  rtx insn;
> +  int i;
> +  struct cgraph_node *node;
> +  struct hard_reg_set_container other_usage;
> +
> +  if (!flag_use_caller_save)
> +    return;
> +
> +  node = cgraph_get_node (current_function_decl);
> +  gcc_assert (node != NULL);
> +
> +  gcc_assert (!node->function_used_regs_initialized);
> +  node->function_used_regs_initialized = 1;
> +
> +  for (insn = get_insns (); insn != NULL_RTX; insn = next_insn (insn))
> +    {
> +      HARD_REG_SET insn_used_regs;
> +
> +      if (!NONDEBUG_INSN_P (insn))
> +    continue;
> +
> +      find_all_hard_reg_sets (insn, &insn_used_regs, false);
> +
> +      if (CALL_P (insn)
> +      && !get_call_reg_set_usage (insn, &insn_used_regs, 
> call_used_reg_set))
> +    {
> +      CLEAR_HARD_REG_SET (node->function_used_regs);
> +      return;
> +    }
> +
> 
> I'd put it before find_all_hard_reg_sets
> 
> +      IOR_HARD_REG_SET (node->function_used_regs, insn_used_regs);
> +    }
> +
> 
> 

insn_used_regs is set by both find_all_hard_reg_sets, and by
get_call_reg_set_usage. If we move the IOR to before find_all_hard_reg_sets,
we're using an undefined value.

> 
> But you can ignore my two last 2 comments.
> 
> The patch is ok for me for trunk at stage1.  But I think you need a 
> formal approval for df-scan.c, arm.c, mips.c, GCC testsuite expect files 
> (lib/target-supports.exp and gcc.target/mips/mips.exp) as I am not a 
> maintainer of these parts although these changes look ok for me.
> 

I'm assuming you've ok'ed patch 1, 2, 3, 4, 6, 8, 9 and the non-df-scan part of 7.

I'll ask other maintainers about the other parts (5, 10 and the df-scan part of 7).

Thanks,
- Tom


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