Skip to content

R
riscv-gcc-1
Commit 178667d2 by Segher Boessenkool Committed by Segher Boessenkool
Options

combine: Remove use_crosses_set_p 

This removes use_crosses_set_p, and uses modified_between_p instead
everywhere it was used.  This improves optimisation.


	* combine.c: Adjust comment.
	(use_crosses_set_p): Delete.
	(can_combine_p): Use modified_between_p instead of use_crosses_set_p.
	(try_combine): Ditto.

From-SVN: r255384
parent 86502ecf
Showing with 14 additions and 62 deletions
gcc/ChangeLog
2017-12-04 Segher Boessenkool <segher@kernel.crashing.org>
* combine.c: Adjust comment.
(use_crosses_set_p): Delete.
(can_combine_p): Use modified_between_p instead of use_crosses_set_p.
(try_combine): Ditto.
2017-12-04 Richard Biener <rguenther@suse.de>
PR tree-optimization/83255
gcc/combine.c
......@@ -39,7 +39,7 @@ along with GCC; see the file COPYING3. If not see
insn as having a logical link to the preceding insn. The same is true
for an insn explicitly using CC0.
We check (with use_crosses_set_p) to avoid combining in such a way
We check (with modified_between_p) to avoid combining in such a way
as to move a computation to a place where its value would be different.
Combination is done by mathematically substituting the previous
......@@ -482,7 +482,6 @@ static void record_dead_and_set_regs_1 (rtx, const_rtx, void *);
static void record_dead_and_set_regs (rtx_insn *);
static int get_last_value_validate (rtx *, rtx_insn *, int, int);
static rtx get_last_value (const_rtx);
static int use_crosses_set_p (const_rtx, int);
static void reg_dead_at_p_1 (rtx, const_rtx, void *);
static int reg_dead_at_p (rtx, rtx_insn *);
static void move_deaths (rtx, rtx, int, rtx_insn *, rtx *);
......@@ -2011,7 +2010,7 @@ can_combine_p (rtx_insn *insn, rtx_insn *i3, rtx_insn *pred ATTRIBUTE_UNUSED,
|| (! all_adjacent
&& (((!MEM_P (src)
|| ! find_reg_note (insn, REG_EQUIV, src))
&& use_crosses_set_p (src, DF_INSN_LUID (insn)))
&& modified_between_p (src, insn, i3))
|| (GET_CODE (src) == ASM_OPERANDS && MEM_VOLATILE_P (src))
|| GET_CODE (src) == UNSPEC_VOLATILE))
/* Don't combine across a CALL_INSN, because that would possibly
......@@ -3699,7 +3698,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
}
else if (m_split_insn && NEXT_INSN (NEXT_INSN (m_split_insn)) == NULL_RTX
&& (next_nonnote_nondebug_insn (i2) == i3
|| ! use_crosses_set_p (PATTERN (m_split_insn), DF_INSN_LUID (i2))))
|| !modified_between_p (PATTERN (m_split_insn), i2, i3)))
{
rtx i2set, i3set;
rtx newi3pat = PATTERN (NEXT_INSN (m_split_insn));
......@@ -3763,7 +3762,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
|| can_change_dest_mode (i2dest, added_sets_2,
GET_MODE (*split)))
&& (next_nonnote_nondebug_insn (i2) == i3
|| ! use_crosses_set_p (*split, DF_INSN_LUID (i2)))
|| !modified_between_p (*split, i2, i3))
/* We can't overwrite I2DEST if its value is still used by
NEWPAT. */
&& ! reg_referenced_p (i2dest, newpat))
......@@ -3954,8 +3953,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
&& GET_CODE (XVECEXP (newpat, 0, 1)) == SET
&& rtx_equal_p (SET_SRC (XVECEXP (newpat, 0, 1)),
XEXP (SET_SRC (XVECEXP (newpat, 0, 0)), 0))
&& ! use_crosses_set_p (SET_SRC (XVECEXP (newpat, 0, 1)),
DF_INSN_LUID (i2))
&& !modified_between_p (SET_SRC (XVECEXP (newpat, 0, 1)), i2, i3)
&& GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != ZERO_EXTRACT
&& GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != STRICT_LOW_PART
&& ! (temp_expr = SET_DEST (XVECEXP (newpat, 0, 1)),
......@@ -4029,7 +4027,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
be first. The PARALLEL might also have been pre-existing in i3,
so we need to make sure that we won't wrongly hoist a SET to i2
that would conflict with a death note present in there. */
if (!use_crosses_set_p (SET_SRC (set1), DF_INSN_LUID (i2))
if (!modified_between_p (SET_SRC (set1), i2, i3)
&& !(REG_P (SET_DEST (set1))
&& find_reg_note (i2, REG_DEAD, SET_DEST (set1)))
&& !(GET_CODE (SET_DEST (set1)) == SUBREG
......@@ -4044,7 +4042,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
newi2pat = set1;
newpat = set0;
}
else if (!use_crosses_set_p (SET_SRC (set0), DF_INSN_LUID (i2))
else if (!modified_between_p (SET_SRC (set0), i2, i3)
&& !(REG_P (SET_DEST (set0))
&& find_reg_note (i2, REG_DEAD, SET_DEST (set0)))
&& !(GET_CODE (SET_DEST (set0)) == SUBREG
......@@ -13661,59 +13659,6 @@ get_last_value (const_rtx x)
return 0;
}
/* Return nonzero if expression X refers to a REG or to memory
that is set in an instruction more recent than FROM_LUID. */
static int
use_crosses_set_p (const_rtx x, int from_luid)
{
const char *fmt;
int i;
enum rtx_code code = GET_CODE (x);
if (code == REG)
{
unsigned int regno = REGNO (x);
unsigned endreg = END_REGNO (x);
#ifdef PUSH_ROUNDING
/* Don't allow uses of the stack pointer to be moved,
because we don't know whether the move crosses a push insn. */
if (regno == STACK_POINTER_REGNUM && PUSH_ARGS)
return 1;
#endif
for (; regno < endreg; regno++)
{
reg_stat_type *rsp = &reg_stat[regno];
if (rsp->last_set
&& rsp->last_set_label == label_tick
&& DF_INSN_LUID (rsp->last_set) > from_luid)
return 1;
}
return 0;
}
if (code == MEM && mem_last_set > from_luid)
return 1;
fmt = GET_RTX_FORMAT (code);
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
if (fmt[i] == 'E')
{
int j;
for (j = XVECLEN (x, i) - 1; j >= 0; j--)
if (use_crosses_set_p (XVECEXP (x, i, j), from_luid))
return 1;
}
else if (fmt[i] == 'e'
&& use_crosses_set_p (XEXP (x, i), from_luid))
return 1;
}
return 0;
}
/* Define three variables used for communication between the following
routines. */
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment