Re: optimization/10024 [3.3 regression] [HP-PA] inline optimization ICE

[Jan Hubicka <jh@suse.cz>]

The following reply was made to PR optimization/10024; it has been noted by GNATS.

From: Jan Hubicka <jh@suse.cz>
To: Richard Henderson <rth@redhat.com>,
	Zack Weinberg <zack@codesourcery.com>, gcc-patches@gcc.gnu.org,
	gcc-gnats@gcc.gnu.org, tausq@debian.org
Cc:  
Subject: Re: optimization/10024 [3.3 regression] [HP-PA] inline optimization ICE
Date: Sun, 6 Apr 2003 14:01:39 +0200

 > On Wed, Mar 26, 2003 at 10:27:54AM -0800, Zack Weinberg wrote:
 > >         * cfgrtl.c (force_nonfallthru_and_redirect): If e is the edge
 > >         we want, use it.
 > 
 > Yes, this is ok for 3.3.
 I am attaching the fix I sent some time ago.  It fixes the checking
 failure as well and fixes force_nonfallthru_and_redirect slightly
 differently - it just bypass the code when redirection is noop.  I
 beleive it is slightly more safe as still we may have instruction with
 multiple outgoing edges where Zacks code would result in misscompilation
 (mine would die, not much better)
 
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 Date: Tue, 1 Apr 2003 19:05:44 +0200
 From: Jan Hubicka <jh@suse.cz>
 To: Mark Mitchell <mark@codesourcery.com>
 Cc: jh@suse.cz, gcc@gcc.gnu.org, gcc-patches@gcc.gnu.org,
 	rth@redhat.com
 Subject: Re: 3.3 PRs
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 > 
 > Jan --
 > 
 > There are a bunch of 3.3 PRs with your name on them.  Let's get these
 > resolved ASAP.
 > 
 > target/9929 ice-on-legal-code:
 > 
 >   Janis tracked this problem to one of your changes.
 > 
 >   You proposed a patch for this, and the discussion ends here:
 > 
 >     http://gcc.gnu.org/ml/gcc-patches/2003-03/msg02281.html
 > 
 >   RTH suggested an alternative way of fixing the problem; please
 >   prepare a patch and submit it.
 > 
 > optimization/8634 wrong-code:
 > 
 >   Janis tracked this problem to one of your changes.
 > 
 > optimization/10056 ice-on-legal-code:
 > 
 >   You checked in a patch for this on March 25:
 > 
 >     Tue Mar 25 20:48:05 CET 2003  Jan Hubicka  <jh@suse.cz>
 > 
 > 	    PR opt/10056
 > 
 >   but the PR is still open.  If you fixed it, would you close the PR?
 > 
 >   If not, what's up?
 > 
 > optimization/10024 ice-on-legal-code:
 > 
 >   This seems like the same issue as 10056.
 
 Actually it is not.  The attached patch should fix it
 
 OK for mainline/branch?  I will install the testcase into compile of
 gcc-torture
  
    extern int * allegro_errno;
    typedef long fixed;
    extern inline int fixfloor (fixed x) { if (x >= 0) return (x >> 16);
    else return ~((~x) >> 16); }
    extern inline int fixtoi (fixed x) { return fixfloor(x) + ((x &
    0x8000) >> 15); }
    extern inline fixed ftofix (double x) { if (x > 32767.0) {
    *allegro_errno = 34; return 0x7FFFFFFF; } if (x < -32767.0) {
    *allegro_errno = 34; return -0x7FFFFFFF; } return (long)(x * 65536.0 +
    (x < 0 ? -0.5 : 0.5)); }
    extern inline double fixtof (fixed x) { return (double)x / 65536.0; }
    extern inline fixed fixdiv (fixed x, fixed y) { if (y == 0) {
    *allegro_errno = 34; return (x < 0) ? -0x7FFFFFFF : 0x7FFFFFFF; } else
    return ftofix(fixtof(x) / fixtof(y)); }
    extern inline fixed itofix (int x) { return x << 16; }
    int foo(int n) { return fixtoi(fixdiv(itofix(512), itofix(n))); }
 
 Tue Apr  1 19:02:47 CEST 2003  Jan Hubicka  <jh@suse.cz>
 
 	PR opt/10024
 	* cfglayout.c (cfg_layout_redirect_edge):  Update the jump.
 	* cfgrtl.c (force_nonfallthru_and_redirect):  Do not special
 	case the fallthru edges when called via cfglayout.c
 
 Index: cfglayout.c
 ===================================================================
 RCS file: /cvs/gcc/gcc/gcc/cfglayout.c,v
 retrieving revision 1.30
 diff -c -3 -p -r1.30 cfglayout.c
 *** cfglayout.c	30 Mar 2003 20:46:56 -0000	1.30
 --- cfglayout.c	1 Apr 2003 17:02:13 -0000
 *************** cfg_layout_redirect_edge (e, dest)
 *** 904,909 ****
 --- 902,914 ----
     src->next_bb = NULL;
     if (e->flags & EDGE_FALLTHRU)
       {
 +       /* Redirect also the branch edges unified with the fallthru one.  */
 +       if (GET_CODE (src->end) == JUMP_INSN
 + 	  && JUMP_LABEL (src->end) == e->dest->head)
 + 	{
 +           if (!redirect_jump (src->end, block_label (dest), 0))
 + 	    abort ();
 + 	}
         /* In case we are redirecting fallthru edge to the branch edge
            of conditional jump, remove it.  */
         if (src->succ->succ_next
 Index: cfgrtl.c
 ===================================================================
 RCS file: /cvs/gcc/gcc/gcc/cfgrtl.c,v
 retrieving revision 1.70
 diff -c -3 -p -r1.70 cfgrtl.c
 *** cfgrtl.c	30 Mar 2003 20:46:56 -0000	1.70
 --- cfgrtl.c	1 Apr 2003 17:02:14 -0000
 *************** force_nonfallthru_and_redirect (e, targe
 *** 926,931 ****
 --- 926,934 ----
        by creating an basic block afterwards to redirect fallthru edge.  */
     if (e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR
         && any_condjump_p (e->src->end)
 +       /* We may be called from cfglayout when the fallthru edges can go
 +          arbitarily.  */
 +       && e->src->next_bb == e->dest
         && JUMP_LABEL (e->src->end) == e->dest->head)
       {
         rtx note;