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re PR rtl-optimization/60651 (Mode switching instructions are sometimes emitted in the wrong order)

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gcc:
        PR rtl-optimization/60651
        * mode-switching.c (optimize_mode_switching): Make sure to emit
        sets of a lower numbered entity before sets of a higher numbered
        entity to a mode of the same or lower priority.
        When creating a seginfo for a basic block that starts with a code
        label, move the insertion point past the code label.
        (new_seginfo): Document and enforce requirement that
        NOTE_INSN_BASIC_BLOCK only appears for empty blocks.
        * doc/tm.texi.in: Document ordering constraint for emitted mode sets.
        * doc/tm.texi: Regenerate.
gcc/testsuite:
        PR rtl-optimization/60651
        * gcc.target/epiphany/mode-switch.c: New test.

From-SVN: r209312
This commit is contained in:
Joern Rennecke 2014-04-11 18:12:53 +00:00 committed by Joern Rennecke
parent 6ace1161e6
commit 473fd99a4c
5 changed files with 45 additions and 3 deletions
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13
gcc/ChangeLog
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@ -1,3 +1,16 @@
2014-04-11 Joern Rennecke <joern.rennecke@embecosm.com>
PR rtl-optimization/60651
* mode-switching.c (optimize_mode_switching): Make sure to emit
sets of a lower numbered entity before sets of a higher numbered
entity to a mode of the same or lower priority.
When creating a seginfo for a basic block that starts with a code
label, move the insertion point past the code label.
(new_seginfo): Document and enforce requirement that
NOTE_INSN_BASIC_BLOCK only appears for empty blocks.
* doc/tm.texi.in: Document ordering constraint for emitted mode sets.
* doc/tm.texi: Regenerate.
2014-01-11 Joern Rennecke <joern.rennecke@embecosm.com>
PR target/60811

2
gcc/doc/tm.texi
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@ -9778,6 +9778,8 @@ for @var{entity}. For any fixed @var{entity}, @code{mode_priority_to_mode}
Generate one or more insns to set @var{entity} to @var{mode}.
@var{hard_reg_live} is the set of hard registers live at the point where
the insn(s) are to be inserted.
Sets of a lower numbered entity will be emitted before sets of a higher
numbered entity to a mode of the same or lower priority.
@end defmac
@node Target Attributes

2
gcc/doc/tm.texi.in
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@ -7447,6 +7447,8 @@ for @var{entity}. For any fixed @var{entity}, @code{mode_priority_to_mode}
Generate one or more insns to set @var{entity} to @var{mode}.
@var{hard_reg_live} is the set of hard registers live at the point where
the insn(s) are to be inserted.
Sets of a lower numbered entity will be emitted before sets of a higher
numbered entity to a mode of the same or lower priority.
@end defmac
@node Target Attributes

26
gcc/mode-switching.c
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@ -96,12 +96,18 @@ static void make_preds_opaque (basic_block, int);
/* This function will allocate a new BBINFO structure, initialized
with the MODE, INSN, and basic block BB parameters. */
with the MODE, INSN, and basic block BB parameters.
INSN may not be a NOTE_INSN_BASIC_BLOCK, unless it is an empty
basic block; that allows us later to insert instructions in a FIFO-like
manner. */
static struct seginfo *
new_seginfo (int mode, rtx insn, int bb, HARD_REG_SET regs_live)
{
struct seginfo *ptr;
gcc_assert (!NOTE_INSN_BASIC_BLOCK_P (insn)
|| insn == BB_END (NOTE_BASIC_BLOCK (insn)));
ptr = XNEW (struct seginfo);
ptr->mode = mode;
ptr->insn_ptr = insn;
@ -534,7 +540,13 @@ optimize_mode_switching (void)
break;
if (e)
{
ptr = new_seginfo (no_mode, BB_HEAD (bb), bb->index, live_now);
rtx ins_pos = BB_HEAD (bb);
if (LABEL_P (ins_pos))
ins_pos = NEXT_INSN (ins_pos);
gcc_assert (NOTE_INSN_BASIC_BLOCK_P (ins_pos));
if (ins_pos != BB_END (bb))
ins_pos = NEXT_INSN (ins_pos);
ptr = new_seginfo (no_mode, ins_pos, bb->index, live_now);
add_seginfo (info + bb->index, ptr);
bitmap_clear_bit (transp[bb->index], j);
}
@ -733,7 +745,15 @@ optimize_mode_switching (void)
{
emitted = true;
if (NOTE_INSN_BASIC_BLOCK_P (ptr->insn_ptr))
emit_insn_after (mode_set, ptr->insn_ptr);
/* We need to emit the insns in a FIFO-like manner,
i.e. the first to be emitted at our insertion
point ends up first in the instruction steam.
Because we made sure that NOTE_INSN_BASIC_BLOCK is
only used for initially empty basic blocks, we
can archive this by appending at the end of
the block. */
emit_insn_after
(mode_set, BB_END (NOTE_BASIC_BLOCK (ptr->insn_ptr)));
else
emit_insn_before (mode_set, ptr->insn_ptr);
}

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2014-04-11 Joern Rennecke <joern.rennecke@embecosm.com>
PR rtl-optimization/60651
* gcc.target/epiphany/mode-switch.c: New test.
2014-04-11 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/58600