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re PR rtl-optimization/18992 (delete_trivially_dead_insns made ineffective for two-address targets)

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PR rtl-optimization/18992
	Back out this patch:
	  2003-10-08  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
	  PR optimization/12142
	  * cse.c (count_reg_usage): In a SET with a REG SET_DEST, count the
	  uses of the register in the SET_SRC.  Remove unnecessary argument.

	Replace it with this:
	* cse.c (count_reg_usage): In INSN, JUMP_INSN and CALL_INSN cases,
	if flag_non_call_exceptions is set and the insn may trap, pass
	pc_rtx as dest for recursion.
	In SET_SRC part of SET case, if dest is already set, pass it down
	unchanged.

From-SVN: r102478
This commit is contained in:
J"orn Rennecke 2005-07-28 11:55:56 +00:00 • committed by Joern Rennecke
parent 7da3fe7701
commit b92ba6ffd9
2 changed files with 56 additions and 24 deletions
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16
gcc/ChangeLog
View file

@ -1,3 +1,19 @@
2005-07-28 J"orn Rennecke <joern.rennecke@st.com>
PR rtl-optimization/18992
Back out this patch:
2003-10-08 John David Anglin <dave.anglin@nrc-cnrc.gc.ca>
PR optimization/12142
* cse.c (count_reg_usage): In a SET with a REG SET_DEST, count the
uses of the register in the SET_SRC. Remove unnecessary argument.
Replace it with this:
* cse.c (count_reg_usage): In INSN, JUMP_INSN and CALL_INSN cases,
if flag_non_call_exceptions is set and the insn may trap, pass
pc_rtx as dest for recursion.
In SET_SRC part of SET case, if dest is already set, pass it down
unchanged.
2005-07-28 Jan Hubicka <jh@suse.cz>
* cfg.c (update_bb_profile_for_threading): Use RDIV.

64
gcc/cse.c
View file

@ -618,7 +618,7 @@ static rtx cse_process_notes (rtx, rtx);
static void invalidate_skipped_set (rtx, rtx, void *);
static void invalidate_skipped_block (rtx);
static rtx cse_basic_block (rtx, rtx, struct branch_path *);
static void count_reg_usage (rtx, int *, int);
static void count_reg_usage (rtx, int *, rtx, int);
static int check_for_label_ref (rtx *, void *);
extern void dump_class (struct table_elt*);
static void get_cse_reg_info_1 (unsigned int regno);
@ -7079,10 +7079,16 @@ check_for_label_ref (rtx *rtl, void *data)
/* Count the number of times registers are used (not set) in X.
COUNTS is an array in which we accumulate the count, INCR is how much
we count each register usage. */
we count each register usage.
Don't count a usage of DEST, which is the SET_DEST of a SET which
contains X in its SET_SRC. This is because such a SET does not
modify the liveness of DEST.
DEST is set to pc_rtx for a trapping insn, which means that we must count
uses of a SET_DEST regardless because the insn can't be deleted here. */
static void
count_reg_usage (rtx x, int *counts, int incr)
count_reg_usage (rtx x, int *counts, rtx dest, int incr)
{
enum rtx_code code;
rtx note;
@ -7095,7 +7101,8 @@ count_reg_usage (rtx x, int *counts, int incr)
switch (code = GET_CODE (x))
{
case REG:
counts[REGNO (x)] += incr;
if (x != dest)
counts[REGNO (x)] += incr;
return;
case PC:
@ -7112,23 +7119,28 @@ count_reg_usage (rtx x, int *counts, int incr)
/* If we are clobbering a MEM, mark any registers inside the address
as being used. */
if (MEM_P (XEXP (x, 0)))
count_reg_usage (XEXP (XEXP (x, 0), 0), counts, incr);
count_reg_usage (XEXP (XEXP (x, 0), 0), counts, NULL_RTX, incr);
return;
case SET:
/* Unless we are setting a REG, count everything in SET_DEST. */
if (!REG_P (SET_DEST (x)))
count_reg_usage (SET_DEST (x), counts, incr);
count_reg_usage (SET_SRC (x), counts, incr);
count_reg_usage (SET_DEST (x), counts, NULL_RTX, incr);
count_reg_usage (SET_SRC (x), counts,
dest ? dest : SET_DEST (x),
incr);
return;
case CALL_INSN:
count_reg_usage (CALL_INSN_FUNCTION_USAGE (x), counts, incr);
/* Fall through. */
case INSN:
case JUMP_INSN:
count_reg_usage (PATTERN (x), counts, incr);
/* We expect dest to be NULL_RTX here. If the insn may trap, mark
this fact by setting DEST to pc_rtx. */
if (flag_non_call_exceptions && may_trap_p (PATTERN (x)))
dest = pc_rtx;
if (code == CALL_INSN)
count_reg_usage (CALL_INSN_FUNCTION_USAGE (x), counts, dest, incr);
count_reg_usage (PATTERN (x), counts, dest, incr);
/* Things used in a REG_EQUAL note aren't dead since loop may try to
use them. */
@ -7143,12 +7155,12 @@ count_reg_usage (rtx x, int *counts, int incr)
Process all the arguments. */
do
{
count_reg_usage (XEXP (eqv, 0), counts, incr);
count_reg_usage (XEXP (eqv, 0), counts, dest, incr);
eqv = XEXP (eqv, 1);
}
while (eqv && GET_CODE (eqv) == EXPR_LIST);
else
count_reg_usage (eqv, counts, incr);
count_reg_usage (eqv, counts, dest, incr);
}
return;
@ -7158,15 +7170,19 @@ count_reg_usage (rtx x, int *counts, int incr)
/* FUNCTION_USAGE expression lists may include (CLOBBER (mem /u)),
involving registers in the address. */
|| GET_CODE (XEXP (x, 0)) == CLOBBER)
count_reg_usage (XEXP (x, 0), counts, incr);
count_reg_usage (XEXP (x, 0), counts, NULL_RTX, incr);
count_reg_usage (XEXP (x, 1), counts, incr);
count_reg_usage (XEXP (x, 1), counts, NULL_RTX, incr);
return;
case ASM_OPERANDS:
/* If the asm is volatile, then this insn cannot be deleted,
and so the inputs *must* be live. */
if (MEM_VOLATILE_P (x))
dest = NULL_RTX;
/* Iterate over just the inputs, not the constraints as well. */
for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--)
count_reg_usage (ASM_OPERANDS_INPUT (x, i), counts, incr);
count_reg_usage (ASM_OPERANDS_INPUT (x, i), counts, dest, incr);
return;
case INSN_LIST:
@ -7180,10 +7196,10 @@ count_reg_usage (rtx x, int *counts, int incr)
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
if (fmt[i] == 'e')
count_reg_usage (XEXP (x, i), counts, incr);
count_reg_usage (XEXP (x, i), counts, dest, incr);
else if (fmt[i] == 'E')
for (j = XVECLEN (x, i) - 1; j >= 0; j--)
count_reg_usage (XVECEXP (x, i, j), counts, incr);
count_reg_usage (XVECEXP (x, i, j), counts, dest, incr);
}
}
@ -7270,11 +7286,11 @@ dead_libcall_p (rtx insn, int *counts)
new = XEXP (note, 0);
/* While changing insn, we must update the counts accordingly. */
count_reg_usage (insn, counts, -1);
count_reg_usage (insn, counts, NULL_RTX, -1);
if (validate_change (insn, &SET_SRC (set), new, 0))
{
count_reg_usage (insn, counts, 1);
count_reg_usage (insn, counts, NULL_RTX, 1);
remove_note (insn, find_reg_note (insn, REG_RETVAL, NULL_RTX));
remove_note (insn, note);
return true;
@ -7285,14 +7301,14 @@ dead_libcall_p (rtx insn, int *counts)
new = force_const_mem (GET_MODE (SET_DEST (set)), new);
if (new && validate_change (insn, &SET_SRC (set), new, 0))
{
count_reg_usage (insn, counts, 1);
count_reg_usage (insn, counts, NULL_RTX, 1);
remove_note (insn, find_reg_note (insn, REG_RETVAL, NULL_RTX));
remove_note (insn, note);
return true;
}
}
count_reg_usage (insn, counts, 1);
count_reg_usage (insn, counts, NULL_RTX, 1);
return false;
}
@ -7317,7 +7333,7 @@ delete_trivially_dead_insns (rtx insns, int nreg)
counts = xcalloc (nreg, sizeof (int));
for (insn = insns; insn; insn = NEXT_INSN (insn))
if (INSN_P (insn))
count_reg_usage (insn, counts, 1);
count_reg_usage (insn, counts, NULL_RTX, 1);
/* Go from the last insn to the first and delete insns that only set unused
registers or copy a register to itself. As we delete an insn, remove
@ -7355,7 +7371,7 @@ delete_trivially_dead_insns (rtx insns, int nreg)
if (! live_insn)
{
count_reg_usage (insn, counts, -1);
count_reg_usage (insn, counts, NULL_RTX, -1);
delete_insn_and_edges (insn);
ndead++;
}