[Bug c/26382] New: [SH] Bug in GCC-3.4.4 and GCC-3.4.5 for crossjumping.

["prafullat at kpitcummins dot com" <gcc-bugzilla at gcc dot gnu dot org>]

Hi,

We have found a bug for SuperH when trying for crossjumping and 
"-fif-conversion2" for gcc-3.4.4 and gcc-3.4.5.

Following is the simple test case,

////////////////////////////////////////////
//xfs2.c

1.      void func (void)
2.      {
3.        if (foo3())
4.          {
5.            foo4(0,1,2,3,4);
6.          }
7.        else 
8.          {
9.            if (foo2())
10.            {
11.               foo4(0,1,2,3,5);
12.            }
13.         }
14.       return;
15.     } 
////////////////////////////////////////////
The command line used for compiling the above is as given below;

#sh-elf-gcc -O1 -fomit-frame-pointer -fcrossjumping -fif-conversion2 -S 

////////////////////////////////////////////
        .file   "xfs2.c"
        .text
        .text
        .align 1
        .global _func
        .type   _func, @function
_func:
        sts.l   pr,@-r15
        mov.l   .L7,r0
        jsr     @r0
        nop
        tst     r0,r0
        add     #-4,r15
        bf/s    .L6
        mov     #4,r1
        mov.l   .L8,r0
        jsr     @r0
        nop
        tst     r0,r0
        bt      .L5
        add     #-4,r15         <-- wrong code ?? (additional stack adjustment  
                                                   here)
        mov     #5,r1
.L6:
        mov.l   r1,@r15
        mov     #0,r4
        mov     #1,r5
        mov     #2,r6
        mov.l   .L9,r0
        jsr     @r0
        mov     #3,r7
        add     #4,r15
.L5:
        lds.l   @r15+,pr
        rts     
        nop
.L10:
        .align 2
.L7:
        .long   _foo3
.L8:
        .long   _foo2
.L9:
        .long   _foo4
        .size   _func, .-_func
        .ident  "GCC: (GNU) 3.4.4"
////////////////////////////////////////////

This code work fine if branch is taken at line number "3". 
But program crashes if branch is not taken.

We have found workaround of using option "fno-crossjumping" OR 
"fno-if-conversion2". 

It seems that, it is a bug in gcc analysis when it tries to optimize 
the code for "crossjumping" as well as using most effective form 
of target specific conditional branching (like bt/s and bf/s ). 

We have further noticed that, this bug does not exist for following,
1. gcc-3.4.4/5 for x86 targets. 
2. gcc-4.0 for SuperH target (also, no crossjumping takes place)

We would like to fix this for SH in gcc-3.4.5. 
I would highly appreciate if someone can guide me to fix this bug.

Thanks in advance.

Regards,
Prafulla Thakare
KPIT Cummins InfoSystems Ltd.
Pune, India

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Free download of GNU based tool-chains for Renesas' SH and H8 Series.
The following site also offers free technical support to its users. 
Visit http://www.kpitgnutools.com for details. 
Latest versions of KPIT GNU tools were released on February 1, 2006.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


-- 
           Summary: [SH] Bug in GCC-3.4.4 and GCC-3.4.5 for crossjumping.
           Product: gcc
           Version: 3.4.5
            Status: UNCONFIRMED
          Severity: critical
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: prafullat at kpitcummins dot com
 GCC build triplet: i686-pc-linux
  GCC host triplet: i686-pc-linux
GCC target triplet: sh-unknown-elf


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26382