From 7f416ffb2875d45370783e94ccab44403d44a1c4 Mon Sep 17 00:00:00 2001
From: "J\"orn Rennecke" <joern.rennecke@st.com>
Date: Wed, 7 Dec 2005 13:31:41 +0000
Subject: Preparation for PR rtl-optimization/20070 / part1
2005-12-07 J"orn Rennecke <joern.rennecke@st.com>
Preparation for PR rtl-optimization/20070 / part1
* basic-block.h (insns_match_p, flow_find_cross_jump): Declare.
* cfgcleanup.c (condjump_equiv_p): New function, broken out of
outgoing_edges_match.
(outgoing_edges_match): Use condjump_equiv_p.
(merge_memattrs, insns_match_p, flow_find_cross_jump): Move from here
into..
* struct-equiv.c: New file.
(death_notes_match_p) New function, broken out of insns_match_p.
* Makefile.in (OBJS-common): Add struct-equiv.o.
(struct-equiv.o): New target.
From-SVN: r108164
---
gcc/struct-equiv.c | 362 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 362 insertions(+)
create mode 100644 gcc/struct-equiv.c
(limited to 'gcc/struct-equiv.c')
diff --git a/gcc/struct-equiv.c b/gcc/struct-equiv.c
new file mode 100644
index 00000000000..0ba1b9d06bc
--- /dev/null
+++ b/gcc/struct-equiv.c
@@ -0,0 +1,362 @@
+/* Control flow optimization code for GNU compiler.
+ Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+ 1999, 2000, 2001, 2002, 2003, 2004, 2005 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 2, 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 COPYING. If not, write to the Free
+Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA. */
+
+/* This file contains helper functions for Cross jumping (tail merging). */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "rtl.h"
+#include "regs.h"
+#include "output.h"
+#include "insn-config.h"
+#include "flags.h"
+#include "recog.h"
+#include "tm_p.h"
+#include "target.h"
+#include "emit-rtl.h"
+
+static void merge_memattrs (rtx, rtx);
+
+
+
+/* Removes the memory attributes of MEM expression
+ if they are not equal. */
+
+void
+merge_memattrs (rtx x, rtx y)
+{
+ int i;
+ int j;
+ enum rtx_code code;
+ const char *fmt;
+
+ if (x == y)
+ return;
+ if (x == 0 || y == 0)
+ return;
+
+ code = GET_CODE (x);
+
+ if (code != GET_CODE (y))
+ return;
+
+ if (GET_MODE (x) != GET_MODE (y))
+ return;
+
+ if (code == MEM && MEM_ATTRS (x) != MEM_ATTRS (y))
+ {
+ if (! MEM_ATTRS (x))
+ MEM_ATTRS (y) = 0;
+ else if (! MEM_ATTRS (y))
+ MEM_ATTRS (x) = 0;
+ else
+ {
+ rtx mem_size;
+
+ if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y))
+ {
+ set_mem_alias_set (x, 0);
+ set_mem_alias_set (y, 0);
+ }
+
+ if (! mem_expr_equal_p (MEM_EXPR (x), MEM_EXPR (y)))
+ {
+ set_mem_expr (x, 0);
+ set_mem_expr (y, 0);
+ set_mem_offset (x, 0);
+ set_mem_offset (y, 0);
+ }
+ else if (MEM_OFFSET (x) != MEM_OFFSET (y))
+ {
+ set_mem_offset (x, 0);
+ set_mem_offset (y, 0);
+ }
+
+ if (!MEM_SIZE (x))
+ mem_size = NULL_RTX;
+ else if (!MEM_SIZE (y))
+ mem_size = NULL_RTX;
+ else
+ mem_size = GEN_INT (MAX (INTVAL (MEM_SIZE (x)),
+ INTVAL (MEM_SIZE (y))));
+ set_mem_size (x, mem_size);
+ set_mem_size (y, mem_size);
+
+ set_mem_align (x, MIN (MEM_ALIGN (x), MEM_ALIGN (y)));
+ set_mem_align (y, MEM_ALIGN (x));
+ }
+ }
+
+ fmt = GET_RTX_FORMAT (code);
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+ {
+ switch (fmt[i])
+ {
+ case 'E':
+ /* Two vectors must have the same length. */
+ if (XVECLEN (x, i) != XVECLEN (y, i))
+ return;
+
+ for (j = 0; j < XVECLEN (x, i); j++)
+ merge_memattrs (XVECEXP (x, i, j), XVECEXP (y, i, j));
+
+ break;
+
+ case 'e':
+ merge_memattrs (XEXP (x, i), XEXP (y, i));
+ }
+ }
+ return;
+}
+
+/* Check if the set of REG_DEAD notes attached to I1 and I2 allows us to
+ go ahead with merging I1 and I2, which otherwise look fine. */
+static bool
+death_notes_match_p (rtx i1 ATTRIBUTE_UNUSED, rtx i2 ATTRIBUTE_UNUSED,
+ int mode ATTRIBUTE_UNUSED)
+{
+#ifdef STACK_REGS
+ /* If cross_jump_death_matters is not 0, the insn's mode
+ indicates whether or not the insn contains any stack-like
+ regs. */
+
+ if ((mode & CLEANUP_POST_REGSTACK) && stack_regs_mentioned (i1))
+ {
+ /* If register stack conversion has already been done, then
+ death notes must also be compared before it is certain that
+ the two instruction streams match. */
+
+ rtx note;
+ HARD_REG_SET i1_regset, i2_regset;
+
+ CLEAR_HARD_REG_SET (i1_regset);
+ CLEAR_HARD_REG_SET (i2_regset);
+
+ for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
+ if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0)))
+ SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
+
+ for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
+ if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0)))
+ SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
+
+ GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
+
+ return false;
+
+ done:
+ ;
+ }
+#endif
+ return true;
+}
+
+/* Return true if I1 and I2 are equivalent and thus can be crossjumped. */
+
+bool
+insns_match_p (int mode, rtx i1, rtx i2)
+{
+ rtx p1, p2;
+
+ /* Verify that I1 and I2 are equivalent. */
+ if (GET_CODE (i1) != GET_CODE (i2))
+ return false;
+
+ p1 = PATTERN (i1);
+ p2 = PATTERN (i2);
+
+ if (GET_CODE (p1) != GET_CODE (p2))
+ return false;
+
+ /* If this is a CALL_INSN, compare register usage information.
+ If we don't check this on stack register machines, the two
+ CALL_INSNs might be merged leaving reg-stack.c with mismatching
+ numbers of stack registers in the same basic block.
+ If we don't check this on machines with delay slots, a delay slot may
+ be filled that clobbers a parameter expected by the subroutine.
+
+ ??? We take the simple route for now and assume that if they're
+ equal, they were constructed identically. */
+
+ if (CALL_P (i1)
+ && (!rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
+ CALL_INSN_FUNCTION_USAGE (i2))
+ || SIBLING_CALL_P (i1) != SIBLING_CALL_P (i2)))
+ return false;
+
+ if (!death_notes_match_p (i1, i2, mode))
+ return false;
+
+ if (reload_completed
+ ? rtx_renumbered_equal_p (p1, p2) : rtx_equal_p (p1, p2))
+ return true;
+
+ /* Do not do EQUIV substitution after reload. First, we're undoing the
+ work of reload_cse. Second, we may be undoing the work of the post-
+ reload splitting pass. */
+ /* ??? Possibly add a new phase switch variable that can be used by
+ targets to disallow the troublesome insns after splitting. */
+ if (!reload_completed)
+ {
+ /* The following code helps take care of G++ cleanups. */
+ rtx equiv1 = find_reg_equal_equiv_note (i1);
+ rtx equiv2 = find_reg_equal_equiv_note (i2);
+
+ if (equiv1 && equiv2
+ /* If the equivalences are not to a constant, they may
+ reference pseudos that no longer exist, so we can't
+ use them. */
+ && (! reload_completed
+ || (CONSTANT_P (XEXP (equiv1, 0))
+ && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))))
+ {
+ rtx s1 = single_set (i1);
+ rtx s2 = single_set (i2);
+ if (s1 != 0 && s2 != 0
+ && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
+ {
+ validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
+ validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
+ if (! rtx_renumbered_equal_p (p1, p2))
+ cancel_changes (0);
+ else if (apply_change_group ())
+ return true;
+ }
+ }
+ }
+
+ return false;
+}
+
+/* Look through the insns at the end of BB1 and BB2 and find the longest
+ sequence that are equivalent. Store the first insns for that sequence
+ in *F1 and *F2 and return the sequence length.
+
+ To simplify callers of this function, if the blocks match exactly,
+ store the head of the blocks in *F1 and *F2. */
+
+int
+flow_find_cross_jump (int mode ATTRIBUTE_UNUSED, basic_block bb1,
+ basic_block bb2, rtx *f1, rtx *f2)
+{
+ rtx i1, i2, last1, last2, afterlast1, afterlast2;
+ int ninsns = 0;
+
+ /* Skip simple jumps at the end of the blocks. Complex jumps still
+ need to be compared for equivalence, which we'll do below. */
+
+ i1 = BB_END (bb1);
+ last1 = afterlast1 = last2 = afterlast2 = NULL_RTX;
+ if (onlyjump_p (i1)
+ || (returnjump_p (i1) && !side_effects_p (PATTERN (i1))))
+ {
+ last1 = i1;
+ i1 = PREV_INSN (i1);
+ }
+
+ i2 = BB_END (bb2);
+ if (onlyjump_p (i2)
+ || (returnjump_p (i2) && !side_effects_p (PATTERN (i2))))
+ {
+ last2 = i2;
+ /* Count everything except for unconditional jump as insn. */
+ if (!simplejump_p (i2) && !returnjump_p (i2) && last1)
+ ninsns++;
+ i2 = PREV_INSN (i2);
+ }
+
+ while (true)
+ {
+ /* Ignore notes. */
+ while (!INSN_P (i1) && i1 != BB_HEAD (bb1))
+ i1 = PREV_INSN (i1);
+
+ while (!INSN_P (i2) && i2 != BB_HEAD (bb2))
+ i2 = PREV_INSN (i2);
+
+ if (i1 == BB_HEAD (bb1) || i2 == BB_HEAD (bb2))
+ break;
+
+ if (!insns_match_p (mode, i1, i2))
+ break;
+
+ merge_memattrs (i1, i2);
+
+ /* Don't begin a cross-jump with a NOTE insn. */
+ if (INSN_P (i1))
+ {
+ /* If the merged insns have different REG_EQUAL notes, then
+ remove them. */
+ rtx equiv1 = find_reg_equal_equiv_note (i1);
+ rtx equiv2 = find_reg_equal_equiv_note (i2);
+
+ if (equiv1 && !equiv2)
+ remove_note (i1, equiv1);
+ else if (!equiv1 && equiv2)
+ remove_note (i2, equiv2);
+ else if (equiv1 && equiv2
+ && !rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
+ {
+ remove_note (i1, equiv1);
+ remove_note (i2, equiv2);
+ }
+
+ afterlast1 = last1, afterlast2 = last2;
+ last1 = i1, last2 = i2;
+ ninsns++;
+ }
+
+ i1 = PREV_INSN (i1);
+ i2 = PREV_INSN (i2);
+ }
+
+#ifdef HAVE_cc0
+ /* Don't allow the insn after a compare to be shared by
+ cross-jumping unless the compare is also shared. */
+ if (ninsns && reg_mentioned_p (cc0_rtx, last1) && ! sets_cc0_p (last1))
+ last1 = afterlast1, last2 = afterlast2, ninsns--;
+#endif
+
+ /* Include preceding notes and labels in the cross-jump. One,
+ this may bring us to the head of the blocks as requested above.
+ Two, it keeps line number notes as matched as may be. */
+ if (ninsns)
+ {
+ while (last1 != BB_HEAD (bb1) && !INSN_P (PREV_INSN (last1)))
+ last1 = PREV_INSN (last1);
+
+ if (last1 != BB_HEAD (bb1) && LABEL_P (PREV_INSN (last1)))
+ last1 = PREV_INSN (last1);
+
+ while (last2 != BB_HEAD (bb2) && !INSN_P (PREV_INSN (last2)))
+ last2 = PREV_INSN (last2);
+
+ if (last2 != BB_HEAD (bb2) && LABEL_P (PREV_INSN (last2)))
+ last2 = PREV_INSN (last2);
+
+ *f1 = last1;
+ *f2 = last2;
+ }
+
+ return ninsns;
+}
--
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