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gcse.c (gcse_constant_p): New function to identify constants suitable for constant propagation... 

* gcse.c (gcse_constant_p): New function to identify constants
	suitable for constant propagation, including COMPARE with two
	integer constant arguments.
	(hash_scan_set): Use gcse_constant_p.
	(find_avail_set): Likewise.
	(cprop_insn): Likewise.
	(do_local_cprop): Likewise.
	(find_implicit_sets): Likewise.
	(find_bypass_set): Likewise.

From-SVN: r65075
This commit is contained in:
Roger Sayle 2003-03-31 05:25:52 +00:00 committed by Roger Sayle
parent af8294418c
commit 6b2d1c9e2b
2 changed files with 39 additions and 9 deletions
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12
gcc/ChangeLog
View File

@ -1,3 +1,15 @@
2003-03-30 Roger Sayle <roger@eyesopen.com>
* gcse.c (gcse_constant_p): New function to identify constants
suitable for constant propagation, including COMPARE with two
integer constant arguments.
(hash_scan_set): Use gcse_constant_p.
(find_avail_set): Likewise.
(cprop_insn): Likewise.
(do_local_cprop): Likewise.
(find_implicit_sets): Likewise.
(find_bypass_set): Likewise.
2003-03-30 Matt Kraai <kraai@alumni.cmu.edu>
* except.h: Remove definition of varray_type.

36
gcc/gcse.c
View File

@ -572,6 +572,7 @@ static void hash_scan_set PARAMS ((rtx, rtx, struct hash_table *));
static void hash_scan_clobber PARAMS ((rtx, rtx, struct hash_table *));
static void hash_scan_call PARAMS ((rtx, rtx, struct hash_table *));
static int want_to_gcse_p PARAMS ((rtx));
static bool gcse_constant_p PARAMS ((rtx));
static int oprs_unchanged_p PARAMS ((rtx, rtx, int));
static int oprs_anticipatable_p PARAMS ((rtx, rtx));
static int oprs_available_p PARAMS ((rtx, rtx));
@ -2155,6 +2156,25 @@ insert_set_in_table (x, insn, table)
}
}
/* Determine whether the rtx X should be treated as a constant for
the purposes of GCSE's constant propagation. */
static bool
gcse_constant_p (x)
rtx x;
{
/* Consider a COMPARE of two integers constant. */
if (GET_CODE (x) == COMPARE
&& GET_CODE (XEXP (x, 0)) == CONST_INT
&& GET_CODE (XEXP (x, 1)) == CONST_INT)
return true;
if (GET_CODE (x) == CONSTANT_P_RTX)
return false;
return CONSTANT_P (x);
}
/* Scan pattern PAT of INSN and add an entry to the hash TABLE (set or
expression one). */
@ -2178,7 +2198,7 @@ hash_scan_set (pat, insn, table)
/* If this is a single set and we are doing constant propagation,
see if a REG_NOTE shows this equivalent to a constant. */
if (table->set_p && (note = find_reg_equal_equiv_note (insn)) != 0
&& CONSTANT_P (XEXP (note, 0)))
&& gcse_constant_p (XEXP (note, 0)))
src = XEXP (note, 0), pat = gen_rtx_SET (VOIDmode, dest, src);
/* Only record sets of pseudo-regs in the hash table. */
@ -2223,8 +2243,7 @@ hash_scan_set (pat, insn, table)
&& REGNO (src) >= FIRST_PSEUDO_REGISTER
&& can_copy_p [GET_MODE (dest)]
&& REGNO (src) != regno)
|| (CONSTANT_P (src)
&& GET_CODE (src) != CONSTANT_P_RTX))
|| gcse_constant_p (src))
/* A copy is not available if its src or dest is subsequently
modified. Here we want to search from INSN+1 on, but
oprs_available_p searches from INSN on. */
@ -4015,7 +4034,7 @@ find_avail_set (regno, insn)
If the source operand changed, we may still use it for the next
iteration of this loop, but we may not use it for substitutions. */
if (CONSTANT_P (src) || oprs_not_set_p (src, insn))
if (gcse_constant_p (src) || oprs_not_set_p (src, insn))
set1 = set;
/* If the source of the set is anything except a register, then
@ -4207,7 +4226,7 @@ cprop_insn (insn, alter_jumps)
src = SET_SRC (pat);
/* Constant propagation. */
if (CONSTANT_P (src))
if (gcse_constant_p (src))
{
if (constprop_register (insn, reg_used->reg_rtx, src, alter_jumps))
{
@ -4328,8 +4347,7 @@ do_local_cprop (x, insn, alter_jumps, libcall_sp)
if (l->in_libcall)
continue;
if (CONSTANT_P (this_rtx)
&& GET_CODE (this_rtx) != CONSTANT_P_RTX)
if (gcse_constant_p (this_rtx))
newcnst = this_rtx;
if (REG_P (this_rtx) && REGNO (this_rtx) >= FIRST_PSEUDO_REGISTER
/* Don't copy propagate if it has attached REG_EQUIV note.
@ -4611,7 +4629,7 @@ find_implicit_sets ()
&& (GET_CODE (cond) == EQ || GET_CODE (cond) == NE)
&& GET_CODE (XEXP (cond, 0)) == REG
&& REGNO (XEXP (cond, 0)) >= FIRST_PSEUDO_REGISTER
&& CONSTANT_P (XEXP (cond, 1)))
&& gcse_constant_p (XEXP (cond, 1)))
{
dest = GET_CODE (cond) == EQ ? BRANCH_EDGE (bb)->dest
: FALLTHRU_EDGE (bb)->dest;
@ -4733,7 +4751,7 @@ find_bypass_set (regno, bb)
abort ();
src = SET_SRC (set->expr);
if (CONSTANT_P (src))
if (gcse_constant_p (src))
result = set;
if (GET_CODE (src) != REG)