[Bug c/11399] New: gcc 3.3.1 miscompiles an if - else if - else statement with O1 on ia64

["ianw at gelato dot unsw dot edu dot au" <gcc-bugzilla at gcc dot gnu dot org>]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11399

           Summary: gcc 3.3.1 miscompiles an if - else if - else statement
                    with O1 on ia64
           Product: gcc
           Version: 3.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ianw at gelato dot unsw dot edu dot au
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: ia64-unknown-linux-gnu
  GCC host triplet: ia64-unknown-linux-gnu
GCC target triplet: ia64-unknown-linux-gnu

gcc 3.3.1 miscompiles the following program at optimisation >= 1 on ia64.  The
program will segfault.  I noticed this when I was building Apache.


--- start test.c ---
#include <stdio.h>
#include <string.h>
 
int retval;
 
const char *if_else(void)
{
 
    if (!strcasecmp("this is", "false")) {
        retval = 0;
    } else if (!strcasecmp("true", "true")) {
        retval = 1;
    } else
        return "a string";
 
    return "ok";
}
 
int main(void)
{
   printf("%s\n", if_else());
}

--- end test.c ---

The offending code from gcc -S

        br.call.sptk.many b0 = strcasecmp#
        ;;
        .mii
        mov r1 = r34
        cmp4.ne p6, p7 = 0, r8
        ;;
        addl r14 = @ltoffx(retval#), r1
        ;;
        .mii
        ld8.mov r15 = [r14], retval#
        addl r14 = @ltoffx("a string"), r1
        ;;
        (p7) addl r14 = 1, r0               <---- set r14 to 1
        ;;
        .mmb
        (p6) ld8.mov r8 = [r14], "a string" <---- segfault
        (p7) st4 [r15] = r14
        (p7) br.cond.dptk .L3

This does compile OK with gcc 3.2 and gcc 3.4