[Bug c/14261] New: Compilation failure due to if-conversion

[Bug c/14261] New: Compilation failure due to if-conversion

[sje at cup dot hp dot com]

The attached program will not compile with -O2 on IA64 linux.  If you turn off
if-conversion it will compile. See
http://gcc.gnu.org/ml/gcc/2004-02/msg01115.html for some analysis from Jim
Wilson.  This was tested with the ToT sources dated 
20040212 and also exists on older GCC compilers for IA64 Linux.

typedef union YYSTYPE {
    double dval;
    int intval;
} YYSTYPE;

YYSTYPE *x;

int
knparse (void)
{
  YYSTYPE yyvsa[200];
  register YYSTYPE *yyvsp;
  YYSTYPE yyval, *x;
  yyvsp = &yyvsa[100];
  if (yyvsp[3].intval > yyvsp[0].intval)
     yyval.intval = yyvsp[3].intval;
  else
     yyval.intval = yyvsp[0].intval;
  *x = yyval;
}

-- 
           Summary: Compilation failure due to if-conversion
           Product: gcc
           Version: 3.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: sje at cup dot hp dot com
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14261

[Bug c/14261] Compilation failure due to if-conversion

[gerald at pfeifer dot com]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gerald at pfeifer dot com,
                   |                            |schwab at suse dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14261

[Bug optimization/14261] Compilation failure due to if-conversion

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c                           |optimization


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14261

[Bug rtl-optimization/14261] ICE due to if-conversion

[giovannibajo at libero dot it]

------- Additional Comments From giovannibajo at libero dot it  2004-08-16 00:32 -------
Confirmed by Jim Wilson, and the submitter says it is not a regression. The 
testcase fails on IA-64, but Jim's analysys points to deficiencies in the 
ifcvt, so I'm keeping this as a rtl-opt bug.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |wilson at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |ice-on-valid-code
   Last reconfirmed|0000-00-00 00:00:00         |2004-08-16 00:32:13
               date|                            |
            Summary|Compilation failure due to  |ICE due to if-conversion
                   |if-conversion               |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14261

[Bug rtl-optimization/14261] ICE due to if-conversion

[roger at eyesopen dot com]

------- Comment #5 from roger at eyesopen dot com  2006-05-15 17:37 -------
This should now be fixed on both mainline and the 4.1 branch.  Thanks Andreas.


-- 

roger at eyesopen dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.1.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14261

[Bug rtl-optimization/14261] ICE due to if-conversion

[krebbel1 at de dot ibm dot com]

------- Comment #4 from krebbel1 at de dot ibm dot com  2006-05-03 08:25 -------
The similar problem occurs on s390x:
http://gcc.gnu.org/ml/gcc-patches/2006-03/msg01795.html

The problem (for ia64 and s390x) is fixed on mainline by:
http://gcc.gnu.org/ml/gcc-patches/2006-04/msg00697.html

which unfortunately revealed a problem with paradoxical subregs on big endian
machines which is fixed by:
http://gcc.gnu.org/ml/gcc-patches/2006-04/msg00951.html

(I've added the PR numbers to the changelog entries afterwards, so the patches
aren't mentioned here automatically.)

For gcc 4.1 I've proposed the following trivial patch, in case the others are
considered to risky for gcc 4.1:

Index: gcc/ifcvt.c
===================================================================
*** gcc/ifcvt.c.orig    2006-03-31 17:03:27.000000000 +0200
--- gcc/ifcvt.c 2006-03-31 17:04:04.000000000 +0200
*************** noce_process_if_block (struct ce_if_bloc
*** 2231,2236 ****
--- 2231,2238 ----
      {
        if (no_new_pseudos || GET_MODE (x) == BLKmode)
        return FALSE;
+       if (GET_CODE (x) == ZERO_EXTRACT)
+       return FALSE;
        x = gen_reg_rtx (GET_MODE (GET_CODE (x) == STRICT_LOW_PART
                                 ? XEXP (x, 0) : x));
      }


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14261

[Bug rtl-optimization/14261] ICE due to if-conversion

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2006-03-04 19:49 -------
*** Bug 26555 has been marked as a duplicate of this bug. ***


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |debian-gcc at lists dot
                   |                            |debian dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14261

[Bug rtl-optimization/14261] ICE due to if-conversion

[roger at eyesopen dot com]

------- Comment #2 from roger at eyesopen dot com  2006-02-26 15:00 -------
I've posted a proposed solution to gcc-patches:
http://gcc.gnu.org/ml/gcc-patches/2006-02/msg01909.html


-- 

roger at eyesopen dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14261