------- Comment #8 from zadeck at naturalbridge dot com 2007-06-23 15:55
-------
Subject: Re: [4.3 Regression] MIPS: FAIL in gcc.dg/cleanup-[8|9|10|11].c
This patch changes dce:deletable_insn_p so that it looks at all of the
top level
clauses in a parallel to make it's decision. It was not keeping insns
that had a top level USE or UNSPEC if they were inside of parallels.
This should fix pr32437 and perhaps other things.
The patch has only been tested on ppc and x86-64. It is harmless on
those platforms.
It is likely to make a difference on pa-risc and mips where there are
parallels that contain top level unspecs.
Ok to commit?
Kenny
2007-06-23 Kenneth Zadeck <[EMAIL PROTECTED]>
PR middle-end/32437
*dce.c (deletable_insn_p): Add extra parameter and recurse if insn
is a PARALLEL.
(prescan_insns_for_dce): Add extra parameter.
Index: dce.c
===================================================================
--- dce.c (revision 125971)
+++ dce.c (working copy)
@@ -58,15 +58,14 @@ static bitmap_obstack dce_tmp_bitmap_obs
static sbitmap marked = NULL;
-/* Return true if INSN a normal instruction that can be deleted by the
- DCE pass. */
+/* Return true if INSN with BODY is a normal instruction that can be
+ deleted by the DCE pass. */
static bool
-deletable_insn_p (rtx insn, bool fast)
+deletable_insn_p (rtx insn, rtx body, bool fast)
{
rtx x;
-
- switch (GET_CODE (PATTERN (insn)))
+ switch (GET_CODE (body))
{
case USE:
case PREFETCH:
@@ -86,7 +85,7 @@ deletable_insn_p (rtx insn, bool fast)
/* A CLOBBER of a dead pseudo register serves no purpose.
That is not necessarily true for hard registers until
after reload. */
- x = XEXP (PATTERN (insn), 0);
+ x = XEXP (body, 0);
return REG_P (x) && (!HARD_REGISTER_P (x) || reload_completed);
}
else
@@ -95,14 +94,23 @@ deletable_insn_p (rtx insn, bool fast)
never be the target of a use-def chain. */
return false;
+ case PARALLEL:
+ {
+ int i;
+ for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
+ if (!deletable_insn_p (insn, XVECEXP (body, 0, i), fast))
+ return false;
+ return true;
+ }
+
default:
if (!NONJUMP_INSN_P (insn))
return false;
- if (volatile_insn_p (PATTERN (insn)))
+ if (volatile_insn_p (body))
return false;
- if (flag_non_call_exceptions && may_trap_p (PATTERN (insn)))
+ if (flag_non_call_exceptions && may_trap_p (body))
return false;
return true;
@@ -361,7 +369,7 @@ prescan_insns_for_dce (bool fast)
rtx note = find_reg_note (insn, REG_LIBCALL_ID, NULL_RTX);
if (note)
mark_libcall (insn, fast);
- else if (deletable_insn_p (insn, fast))
+ else if (deletable_insn_p (insn, PATTERN (insn), fast))
mark_nonreg_stores (PATTERN (insn), insn, fast);
else
mark_insn (insn, fast);
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32437
