[Bug c/60527] New: Incorrectly removed if statement while doing int arithmetics

[nicklas.ekstrand at sonymobile dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60527

            Bug ID: 60527
           Summary: Incorrectly removed if statement while doing int
                    arithmetics
           Product: gcc
           Version: 4.6.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nicklas.ekstrand at sonymobile dot com

Created attachment 32349
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32349&action=edit
Test program modtest.c

In the following code:

static int getZ() {
    int tmp;
    Z = Z * A + B;
    tmp = Z;
    if (tmp == INT_MIN)
        tmp++;
    if (tmp < 0)
        tmp = -tmp;
    return tmp % MEMSIZE;
}

The if-statement tmp==INT_MIN is optimized away when using -O2 or higher, e.g.,

$ gcc -Wall -Wextra -g -O2 modtest.c -o pc_modtest -lrt
$ ./pc_modtest 
arr=0x7fc1608be010
i=0 A=945 B=411
z1=231029 z2=-7483648
Segmentation fault

When using -O0 the problem doesn't happen and the program will not cause a
segmentation fault.