mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-04-21 04:50:24 +08:00
Code Issues Packages Projects Releases Wiki Activity

(subst_prev_insn): New variable.

Browse Source 
(try_combine): Set it.
(get_last_value): Use it.

From-SVN: r9396
This commit is contained in:
Jim Wilson 1995-04-17 13:49:59 -07:00
parent 4ffeab028f
commit 0d9641d106
1 changed files with 13 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
gcc/combine.c
View File

@ -173,6 +173,11 @@ static int last_call_cuid;
static rtx subst_insn;
/* This is an insn that belongs before subst_insn, but is not currently
on the insn chain. */
static rtx subst_prev_insn;
/* This is the lowest CUID that `subst' is currently dealing with.
get_last_value will not return a value if the register was set at or
after this CUID. If not for this mechanism, we could get confused if
@ -1358,8 +1363,9 @@ try_combine (i3, i2, i1)
never appear in the insn stream so giving it the same INSN_UID
as I2 will not cause a problem. */
i1 = gen_rtx (INSN, VOIDmode, INSN_UID (i2), 0, i2,
XVECEXP (PATTERN (i2), 0, 1), -1, 0, 0);
subst_prev_insn = i1
= gen_rtx (INSN, VOIDmode, INSN_UID (i2), 0, i2,
XVECEXP (PATTERN (i2), 0, 1), -1, 0, 0);
SUBST (PATTERN (i2), XVECEXP (PATTERN (i2), 0, 0));
SUBST (XEXP (SET_SRC (PATTERN (i2)), 0),
@ -9943,9 +9949,12 @@ get_last_value (x)
/* If the value was set in a later insn than the ones we are processing,
we can't use it even if the register was only set once, but make a quick
check to see if the previous insn set it to something. This is commonly
the case when the same pseudo is used by repeated insns. */
the case when the same pseudo is used by repeated insns.
if (INSN_CUID (reg_last_set[regno]) >= subst_low_cuid)
This does not work if there exists an instruction which is temporarily
not on the insn chain. */
if (INSN_CUID (reg_last_set[regno]) >= subst_low_cuid && ! subst_prev_insn)
{
rtx insn, set;