mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2024-12-23 05:39:02 +08:00
Code Issues Packages Projects Releases Wiki Activity

combine.c (nonzero_bits): Allow single-ly set registers to be anywere in the function only if...

Browse Source 
* combine.c (nonzero_bits) : Allow single-ly set registers to be
	anywere in the function only if they are pseudos and set before
	being used (not live at the start of the function).
	(num_sign_bit_copies) : Same.
	(get_last_value_validate) : Same.
	(get_last_value) : Same.

From-SVN: r28871
This commit is contained in:
Gavin Romig-Koch 1999-08-25 19:29:43 +00:00 committed by Gavin Romig-Koch
parent 95c5608516
commit 57cf50a464
2 changed files with 37 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
gcc/ChangeLog
View File

@ -1,3 +1,12 @@
Wed Aug 25 15:27:22 1999 Gavin Romig-Koch <gavin@cygnus.com>
* combine.c (nonzero_bits) : Allow single-ly set registers to be
anywere in the function only if they are pseudos and set before
being used (not live at the start of the function).
(num_sign_bit_copies) : Same.
(get_last_value_validate) : Same.
(get_last_value) : Same.
Wed Aug 25 11:13:29 1999 Richard Henderson <rth@cygnus.com>
* loop.c (express_from): Try harder to unify (* c N) and (* c M)

39
gcc/combine.c
View File

@ -7521,8 +7521,11 @@ nonzero_bits (x, mode)
if (reg_last_set_value[REGNO (x)] != 0
&& reg_last_set_mode[REGNO (x)] == mode
&& (REG_N_SETS (REGNO (x)) == 1
|| reg_last_set_label[REGNO (x)] == label_tick)
&& (reg_last_set_label[REGNO (x)] == label_tick
|| (REGNO (x) >= FIRST_PSEUDO_REGISTER
&& REG_N_SETS (REGNO (x)) == 1
&& ! REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start,
REGNO (x))))
&& INSN_CUID (reg_last_set[REGNO (x)]) < subst_low_cuid)
return reg_last_set_nonzero_bits[REGNO (x)];
@ -7911,8 +7914,11 @@ num_sign_bit_copies (x, mode)
if (reg_last_set_value[REGNO (x)] != 0
&& reg_last_set_mode[REGNO (x)] == mode
&& (REG_N_SETS (REGNO (x)) == 1
|| reg_last_set_label[REGNO (x)] == label_tick)
&& (reg_last_set_label[REGNO (x)] == label_tick
|| (REGNO (x) >= FIRST_PSEUDO_REGISTER
&& REG_N_SETS (REGNO (x)) == 1
&& ! REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start,
REGNO (x))))
&& INSN_CUID (reg_last_set[REGNO (x)]) < subst_low_cuid)
return reg_last_set_sign_bit_copies[REGNO (x)];
@ -10734,9 +10740,11 @@ get_last_value_validate (loc, insn, tick, replace)
for (j = regno; j < endregno; j++)
if (reg_last_set_invalid[j]
/* If this is a pseudo-register that was only set once, it is
always valid. */
|| (! (regno >= FIRST_PSEUDO_REGISTER && REG_N_SETS (regno) == 1)
/* If this is a pseudo-register that was only set once and not
live at the beginning of the function, it is always valid. */
|| (! (regno >= FIRST_PSEUDO_REGISTER
&& REG_N_SETS (regno) == 1
&& ! REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
&& reg_last_set_label[j] > tick))
{
if (replace)
@ -10795,12 +10803,21 @@ get_last_value (x)
regno = REGNO (x);
value = reg_last_set_value[regno];
/* If we don't have a value or if it isn't for this basic block,
return 0. */
/* If we don't have a value, or if it isn't for this basic block and
it's either a hard register, set more than once, or it's a live
at the beginning of the function, return 0.
Because if it's not live at the beginnning of the function then the reg
is always set before being used (is never used without being set).
And, if it's set only once, and it's always set before use, then all
uses must have the same last value, even if it's not from this basic
block. */
if (value == 0
|| (REG_N_SETS (regno) != 1
&& reg_last_set_label[regno] != label_tick))
|| (reg_last_set_label[regno] != label_tick
&& (regno < FIRST_PSEUDO_REGISTER
|| REG_N_SETS (regno) != 1
|| REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))))
return 0;
/* If the value was set in a later insn than the ones we are processing,