OpenE2K/gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

(reg_known_equiv_p): New variable.

Browse Source 
(init_alias_analysis): Allocate and compute reg_known_equiv_p.
(sched_analyze_1): Reenable code for REG_EQUIV notes, using
reg_known_equiv_p so that it is only used on REG_EQUIV notes.
(sched_analyze_2): Likewise.  Only pass memory addresses to the
sched_analyze_2 call.

From-SVN: r3746
This commit is contained in:
Jim Wilson 1993-03-15 11:48:38 -08:00
parent 581c26f946
commit c3af9fc81e
1 changed files with 36 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

69
gcc/sched.c
View File

@ -294,6 +294,19 @@ void schedule_insns ();
for pseudo-register N. */
static rtx *reg_known_value;
/* Vector recording for each reg_known_value whether it is due to a
REG_EQUIV note. Future passes (viz., reload) may replace the
pseudo with the equivalent expression and so we account for the
dependences that would be introduced if that happens. */
/* ??? This is a problem only on the Convex. The REG_EQUIV notes created in
assign_parms mention the arg pointer, and there are explicit insns in the
RTL that modify the arg pointer. Thus we must ensure that such insns don't
get scheduled across each other because that would invalidate the REG_EQUIV
notes. One could argue that the REG_EQUIV notes are wrong, but solving
the problem in the scheduler will likely give better code, so we do it
here. */
static char *reg_known_equiv_p;
/* Indicates number of valid entries in reg_known_value. */
static int reg_known_value_size;
@ -341,6 +354,12 @@ init_alias_analysis ()
bzero (reg_known_value+FIRST_PSEUDO_REGISTER,
(maxreg-FIRST_PSEUDO_REGISTER) * sizeof (rtx));
reg_known_equiv_p
= (char *) oballoc ((maxreg-FIRST_PSEUDO_REGISTER) * sizeof (char))
- FIRST_PSEUDO_REGISTER;
bzero (reg_known_equiv_p+FIRST_PSEUDO_REGISTER,
(maxreg-FIRST_PSEUDO_REGISTER) * sizeof (char));
/* Fill in the entries with known constant values. */
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
if ((set = single_set (insn)) != 0
@ -350,7 +369,11 @@ init_alias_analysis ()
&& reg_n_sets[REGNO (SET_DEST (set))] == 1)
|| (note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) != 0)
&& GET_CODE (XEXP (note, 0)) != EXPR_LIST)
reg_known_value[REGNO (SET_DEST (set))] = XEXP (note, 0);
{
int regno = REGNO (SET_DEST (set));
reg_known_value[regno] = XEXP (note, 0);
reg_known_equiv_p[regno] = REG_NOTE_KIND (note) == REG_EQUIV;
}
/* Fill in the remaining entries. */
while (--maxreg >= FIRST_PSEUDO_REGISTER)
@ -1622,24 +1645,13 @@ sched_analyze_1 (x, insn)
add_dependence (insn, reg_last_sets[regno], REG_DEP_OUTPUT);
reg_last_sets[regno] = insn;
#if 0
/* ??? This code has two serious problems:
1) It can cause an infinite loop if regno is mentioned in
its reg_known_value.
2) It can cause execution time exponential in the size of the
input if there are long chains of reg_known_values pointing
to other reg_known_values.
This code was specifically added to handle fake argument pointers.
It may need to be rewritten to just handle that specific case. */
/* Pseudos that are REG_EQUIV to something may be replaced
by that during reloading, so we can potentially read
quantities mentioned in those addresses. */
if (! reload_completed)
if (reg_known_value[regno] != regno_reg_rtx[regno])
if (GET_CODE (reg_known_value[regno]) == MEM)
sched_analyze_2 (XEXP (reg_known_value[regno], 0), insn);
#endif
by that during reloading. We need only add dependencies for
the address in the REG_EQUIV note. */
if (! reload_completed
&& reg_known_equiv_p[regno]
&& GET_CODE (reg_known_value[regno]) == MEM)
sched_analyze_2 (XEXP (reg_known_value[regno], 0), insn);
/* Don't let it cross a call after scheduling if it doesn't
already cross one. */
@ -1793,22 +1805,13 @@ sched_analyze_2 (x, insn)
if (reg_last_sets[regno])
add_dependence (insn, reg_last_sets[regno], 0);
#if 0
/* ??? This code has two serious problems:
1) It can cause an infinite loop if regno is mentioned in
its reg_known_value.
2) It can cause execution time exponential in the size of the
input if there are long chains of reg_known_values pointing
to other reg_known_values.
This code was specifically added to handle fake argument pointers.
It may need to be rewritten to just handle that specific case. */
/* Pseudos that are REG_EQUIV to something may be replaced
by that, so we depend on anything mentioned there too. */
if (! reload_completed)
if (reg_known_value[regno] != regno_reg_rtx[regno])
sched_analyze_2 (reg_known_value[regno], insn);
#endif
by that during reloading. We need only add dependencies for
the address in the REG_EQUIV note. */
if (! reload_completed
&& reg_known_equiv_p[regno]
&& GET_CODE (reg_known_value[regno]) == MEM)
sched_analyze_2 (XEXP (reg_known_value[regno], 0), insn);
/* If the register does not already cross any calls, then add this
insn to the sched_before_next_call list so that it will still