REG_INC notes going AWOL during reload
Michael Hayes
m.hayes@elec.canterbury.ac.nz
Sun Feb 28 18:15:00 GMT 1999
Michael Hayes writes:
> Jeffrey A Law writes:
> > Handling it in reload is also a little cleaner -- as far as the rest of
> > the compiler is concerned reload kept the REG_INC notes accurate.
>
> In the interim, here's a patch to flow.c so that it is not dependent
> upon the accuracy of the REG_INC notes. This fixes the dead store bug.
Please ignore this previous patch I sent for the meantime since I have
rewritten it to take advantage of the following patch which correctly
restores the REG_INC notes in reload. Note, I don't have access to a
machine with autoincrement addressing modes that I can bootstrap with;
however, it appears to work correctly.
Wed Feb 24 11:07:27 1999 Michael Hayes <m.hayes@elec.canterbury.ac.nz>
* rtlanal.c (auto_inc_p): New function.
* rtl.h (auto_inc_p): Prototype it.
* reload1.c (add_auto_inc_notes): New function.
(reload): Strip REG_INC notes and call add_auto_inc_notes
for each insn to restore them correctly.
Index: rtlanal.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/rtlanal.c,v
retrieving revision 1.31
diff -c -3 -p -r1.31 rtlanal.c
*** rtlanal.c 1999/02/19 14:49:57 1.31
--- rtlanal.c 1999/02/23 22:23:45
*************** regno_use_in (regno, x)
*** 2253,2255 ****
--- 2253,2279 ----
return NULL_RTX;
}
+
+
+ /* Return 1 if X is an autoincrement side effect and the register is
+ not the stack pointer. */
+ int
+ auto_inc_p (x)
+ rtx x;
+ {
+ switch (GET_CODE (x))
+ {
+ case PRE_INC:
+ case POST_INC:
+ case PRE_DEC:
+ case POST_DEC:
+ case PRE_MODIFY:
+ case POST_MODIFY:
+ /* There are no REG_INC notes for SP. */
+ if (XEXP (x, 0) != stack_pointer_rtx)
+ return 1;
+ default:
+ break;
+ }
+ return 0;
+ }
Index: rtl.h
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/rtl.h,v
retrieving revision 1.86
diff -c -3 -p -r1.86 rtl.h
*** rtl.h 1999/02/08 21:39:31 1.86
--- rtl.h 1999/02/23 22:23:49
*************** typedef int (*rtx_function)
*** 1038,1043 ****
--- 1038,1044 ----
extern int for_each_rtx PROTO((rtx *, rtx_function, void *));
extern int insn_first_p PROTO((rtx, rtx));
extern rtx regno_use_in PROTO((int, rtx));
+ extern int auto_inc_p PROTO((rtx));
/* flow.c */
Index: reload1.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/reload1.c,v
retrieving revision 1.129
diff -c -3 -p -r1.129 reload1.c
*** reload1.c 1999/02/10 09:13:41 1.129
--- reload1.c 1999/02/23 22:24:03
*************** static void reload_combine_note_use PROT
*** 443,448 ****
--- 443,451 ----
static void reload_combine_note_store PROTO((rtx, rtx));
static void reload_cse_move2add PROTO((rtx));
static void move2add_note_store PROTO((rtx, rtx));
+ #ifdef AUTO_INC_DEC
+ static void add_auto_inc_notes PROTO((rtx, rtx));
+ #endif
/* Initialize the reload pass once per compilation. */
*************** reload (first, global, dumpfile)
*** 1124,1134 ****
which are only valid during and after reload. */
reload_completed = 1;
! /* Make a pass over all the insns and delete all USEs which we inserted
! only to tag a REG_EQUAL note on them. Remove all REG_DEAD and REG_UNUSED
! notes. Delete all CLOBBER insns and simplify (subreg (reg)) operands.
! Also remove all REG_RETVAL and REG_LIBCALL notes since they are no longer
! useful or accurate. */
for (insn = first; insn; insn = NEXT_INSN (insn))
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
--- 1127,1139 ----
which are only valid during and after reload. */
reload_completed = 1;
! /* Make a pass over all the insns and delete all USEs which we
! inserted only to tag a REG_EQUAL note on them. Remove all
! REG_DEAD and REG_UNUSED notes. Delete all CLOBBER insns and
! simplify (subreg (reg)) operands. Also remove all REG_RETVAL and
! REG_LIBCALL notes since they are no longer useful or accurate.
! Strip and regenerate REG_INC notes that may have been moved
! around. */
for (insn = first; insn; insn = NEXT_INSN (insn))
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
*************** reload (first, global, dumpfile)
*** 1150,1155 ****
--- 1155,1161 ----
{
if (REG_NOTE_KIND (*pnote) == REG_DEAD
|| REG_NOTE_KIND (*pnote) == REG_UNUSED
+ || REG_NOTE_KIND (*pnote) == REG_INC
|| REG_NOTE_KIND (*pnote) == REG_RETVAL
|| REG_NOTE_KIND (*pnote) == REG_LIBCALL)
*pnote = XEXP (*pnote, 1);
*************** reload (first, global, dumpfile)
*** 1157,1162 ****
--- 1163,1172 ----
pnote = &XEXP (*pnote, 1);
}
+ #ifdef AUTO_INC_DEC
+ add_auto_inc_notes (insn, PATTERN (insn));
+ #endif
+
/* And simplify (subreg (reg)) if it appears as an operand. */
cleanup_subreg_operands (insn);
}
*************** move2add_note_store (dst, set)
*** 10113,10115 ****
--- 10123,10155 ----
}
}
}
+
+ #ifdef AUTO_INC_DEC
+ static void
+ add_auto_inc_notes (insn, x)
+ rtx insn;
+ rtx x;
+ {
+ enum rtx_code code = GET_CODE (x);
+ char *fmt;
+ int i, j;
+
+ if (code == MEM && auto_inc_p (XEXP (x, 0)))
+ {
+ REG_NOTES (insn)
+ = gen_rtx_EXPR_LIST (REG_INC, XEXP (XEXP (x, 0), 0), REG_NOTES (insn));
+ return;
+ }
+
+ /* Scan all the operand sub-expressions. */
+ fmt = GET_RTX_FORMAT (code);
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+ {
+ if (fmt[i] == 'e')
+ add_auto_inc_notes (insn, XEXP (x, i));
+ else if (fmt[i] == 'E')
+ for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+ add_auto_inc_notes (insn, XVECEXP (x, i, j));
+ }
+ }
+ #endif
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