[PATCH] Speedup -Og

Richard Biener rguenther@suse.de
Wed Sep 3 14:14:00 GMT 2014

I seem to have lost this patch in my dev tree for some reason.
After introducing --param max-combine-insns it was the idea
to restrict combine to two-insn combines for -Og as combine
is a major RTL compile-time hog.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.


2014-09-03  Richard Biener  <rguenther@suse.de>

	* opts.c (default_options_optimization): Adjust
	max-combine-insns to 2 for -Og.

Index: gcc/opts.c
*** gcc/opts.c	(revision 214810)
--- gcc/opts.c	(working copy)
*************** default_options_optimization (struct gcc
*** 636,641 ****
--- 637,648 ----
  			   default_param_value (PARAM_MIN_CROSSJUMP_INSNS),
  			   opts->x_param_values, opts_set->x_param_values);
+   /* Restrict the amount of work combine does at -Og while retaining
+      most of its useful transforms.  */
+   if (opts->x_optimize_debug)
+     maybe_set_param_value (PARAM_MAX_COMBINE_INSNS, 2,
+ 			   opts->x_param_values, opts_set->x_param_values);
    /* Allow default optimizations to be specified on a per-machine basis.  */
    maybe_default_options (opts, opts_set,

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