gcc/

2012-03-31  Kenneth Zadeck  <zadeck@naturalbridge.com>
	    Richard Sandiford  <r.sandiford@uk.ibm.com>

	* Makefile.in (lower-subreg.o, target-globals.o): Depend on
	lower-subreg.h.
	* lower-subreg.h: New file.
	* target-globals.h (this_target_lower_subreg): Declare.
	(target_globals): Add lower_subreg;
	(restore_target_globals): Restore this_target_lower_subreg.
	* target-globals.c: Include it.
	(default_target_globals): Add default_target_lower_subreg.
	(save_target_globals): Initialize target_lower_subreg.
	* rtl.h (init_lower_subreg): Added declaration.
	* toplev.c (backend_init_target): Call initializer for lower-subreg
	pass.
	* lower-subreg.c (LOG_COSTS, FORCE_LOWERING): New macros.
	(default_target_lower_subreg): New variable.
	(this_target_lower_subreg): Likewise.
	(twice_word_mode, choices): New macros.
	(shift_cost, compute_splitting_shift, compute_costs)
	(init_lower_subreg): New functions.
	(resolve_simple_move): Add speed_p argument.  Check choices.
	(find_pseudo_copy): Don't check the mode size here.
	(resolve_simple_move): Assert the mode size.
	(find_decomposable_shift_zext): Add speed_p argument and return
	a bool.  Check choices.
	(resolve_shift_zext): Add comment.
	(dump_shift_choices, dump_choices): New functions.
	(decompose_multiword_subregs): Dump list of profitable
	transformations.  Add code to skip non profitable transformations.
	Update calls to simple_move and find_decomposable_shift_zext.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@187015 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 59 insertions, 0 deletions

diff --git a/gcc/lower-subreg.h b/gcc/lower-subreg.h
new file mode 100644
index 00000000000..5c960dbfd09
--- /dev/null
+++ b/gcc/lower-subreg.h
@@ -0,0 +1,59 @@
+/* Target-dependent costs for lower-subreg.c.
+   Copyright (C) 2012 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option; any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef LOWER_SUBREG_H
+#define LOWER_SUBREG_H 1
+
+/* Information about whether, and where, lower-subreg should be applied.  */
+struct lower_subreg_choices {
+  /* A boolean vector for move splitting that is indexed by mode and is
+     true for each mode that is to have its copies split.  */
+  bool move_modes_to_split[MAX_MACHINE_MODE];
+
+  /* True if zero-extensions from word_mode to twice_word_mode should
+     be split.  */
+  bool splitting_zext;
+
+  /* Index X is true if twice_word_mode shifts by X + BITS_PER_WORD
+     should be split.  */
+  bool splitting_ashift[MAX_BITS_PER_WORD];
+  bool splitting_lshiftrt[MAX_BITS_PER_WORD];
+
+  /* True if there is at least one mode that is worth splitting.  */
+  bool something_to_do;
+};
+
+/* Target-specific information for the subreg lowering pass.  */
+struct target_lower_subreg {
+  /* An integer mode that is twice as wide as word_mode.  */
+  enum machine_mode x_twice_word_mode;
+
+  /* What we have decided to do when optimizing for size (index 0)
+     and speed (index 1).  */
+  struct lower_subreg_choices x_choices[2];
+};
+
+extern struct target_lower_subreg default_target_lower_subreg;
+#if SWITCHABLE_TARGET
+extern struct target_lower_subreg *this_target_lower_subreg;
+#else
+#define this_target_lower_subreg (&default_target_lower_subreg)
+#endif
+
+#endif