On Tue, Jun 23, 2015 at 09:52:01AM +0100, Jakub Jelinek wrote:
> On Tue, Jun 23, 2015 at 09:18:52AM +0100, James Greenhalgh wrote:
> > This patch fixes the issue by always calling get_move_ratio in the SRA
> > code, ensuring that an up-to-date value is used.
> >
> > Unfortunately, this means we have to use 0 as a sentinel value for
> > the parameter - indicating no user override of the feature - and
> > therefore cannot use it to disable scalarization. However, there
> > are other ways to disable scalarazation (-fno-tree-sra) so this is not
> > a great loss.
>
> You can handle even that.
>
<snip>
> enum compiler_param param
> = optimize_function_for_size_p (cfun)
> ? PARAM_SRA_MAX_SCALARIZATION_SIZE_SIZE
> : PARAM_SRA_MAX_SCALARIZATION_SIZE_SPEED;
> unsigned max_scalarization_size = PARAM_VALUE (param) * BITS_PER_UNIT;
> if (!max_scalarization_size && !global_options_set.x_param_values[param])
>
> Then it will handle explicit --param sra-max-scalarization-size-Os*=0
> differently from implicit 0.
Ah hah! OK, I've respun the patch removing this extra justification in
the documentation and reshuffling the logic a little.
> OT, shouldn't max_scalarization_size be at least unsigned HOST_WIDE_INT,
> so that it doesn't overflow for larger values (0x40000000 etc.)?
> Probably need some cast in the multiplication to avoid UB in the compiler.
I've increased the size of max_scalarization_size to a UHWI in this spin.
Bootstrapped and tested on AArch64 and x86-64 with no issues and checked
to see the PR is fixed.
OK for trunk, and gcc-5 in a few days?
Thanks,
James
---
gcc/
2015-06-23 James Greenhalgh <james.greenha...@arm.com>
PR tree-optimization/66119
* toplev.c (process_options): Don't set up default values for
the sra_max_scalarization_size_{speed,size} parameters.
* tree-sra (analyze_all_variable_accesses): If no values
have been set for the sra_max_scalarization_size_{speed,size}
parameters, call get_move_ratio to get target defaults.
diff --git a/gcc/toplev.c b/gcc/toplev.c
index 2f43a89..902bfc7 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -1301,20 +1301,6 @@ process_options (void)
so we can correctly initialize debug output. */
no_backend = lang_hooks.post_options (&main_input_filename);
- /* Set default values for parameters relation to the Scalar Reduction
- of Aggregates passes (SRA and IP-SRA). We must do this here, rather
- than in opts.c:default_options_optimization as historically these
- tuning heuristics have been based on MOVE_RATIO, which on some
- targets requires other symbols from the backend. */
- maybe_set_param_value
- (PARAM_SRA_MAX_SCALARIZATION_SIZE_SPEED,
- get_move_ratio (true) * UNITS_PER_WORD,
- global_options.x_param_values, global_options_set.x_param_values);
- maybe_set_param_value
- (PARAM_SRA_MAX_SCALARIZATION_SIZE_SIZE,
- get_move_ratio (false) * UNITS_PER_WORD,
- global_options.x_param_values, global_options_set.x_param_values);
-
/* Some machines may reject certain combinations of options. */
targetm.target_option.override ();
diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index 8e34244..5f573f6 100644
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -2549,11 +2549,20 @@ analyze_all_variable_accesses (void)
bitmap tmp = BITMAP_ALLOC (NULL);
bitmap_iterator bi;
unsigned i;
- unsigned max_scalarization_size
- = (optimize_function_for_size_p (cfun)
- ? PARAM_VALUE (PARAM_SRA_MAX_SCALARIZATION_SIZE_SIZE)
- : PARAM_VALUE (PARAM_SRA_MAX_SCALARIZATION_SIZE_SPEED))
- * BITS_PER_UNIT;
+ bool optimize_speed_p = !optimize_function_for_size_p (cfun);
+
+ enum compiler_param param = optimize_speed_p
+ ? PARAM_SRA_MAX_SCALARIZATION_SIZE_SPEED
+ : PARAM_SRA_MAX_SCALARIZATION_SIZE_SIZE;
+
+ /* If the user didn't set PARAM_SRA_MAX_SCALARIZATION_SIZE_<...>,
+ fall back to a target default. */
+ unsigned HOST_WIDE_INT max_scalarization_size
+ = global_options_set.x_param_values[param]
+ ? PARAM_VALUE (param)
+ : get_move_ratio (optimize_speed_p) * UNITS_PER_WORD;
+
+ max_scalarization_size *= BITS_PER_UNIT;
EXECUTE_IF_SET_IN_BITMAP (candidate_bitmap, 0, i, bi)
if (bitmap_bit_p (should_scalarize_away_bitmap, i)
