[Bug target/68986] [5/6 Regression] internal compiler error: Segmentation fault

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68986

Markus Trippelsdorf <trippels at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |trippels at gcc dot gnu.org
      Known to work|                            |4.9.3
            Summary|internal compiler error:    |[5/6 Regression] internal
                   |Segmentation fault          |compiler error:
                   |                            |Segmentation fault

--- Comment #4 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
PR69454 testcase only crashes with gcc-6:

markus@x4 VEX % cat guest_amd64_helpers.i
typedef struct { long long w64[2]; } V128;
extern V128* fn2(void);
long long a;
V128 b;
void fn1() {
  V128 *c = fn2();
  c->w64[0] = a ^ b.w64[0];
}

markus@x4 VEX % gcc -c -m32 -mpreferred-stack-boundary=2 -O2
guest_amd64_helpers.i
guest_amd64_helpers.i: In function ‘fn1’:
guest_amd64_helpers.i:8:1: internal compiler error: Segmentation fault
 }
 ^

0xb2051f crash_signal
        ../../gcc/gcc/toplev.c:335
0x7f543f74614f ???
       
/home/markus/glibc/signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
0xe3d804 ix86_expand_prologue()
        ../../gcc/gcc/config/i386/i386.c:12751
0xff543a gen_prologue()
        ../../gcc/gcc/config/i386/i386.md:12451
0xe248e8 target_gen_prologue
        ../../gcc/gcc/config/i386/i386.md:18466
0x87a6ff thread_prologue_and_epilogue_insns()
        ../../gcc/gcc/function.c:6037
0x87b1d2 rest_of_handle_thread_prologue_and_epilogue
        ../../gcc/gcc/function.c:6588
0x87b1d2 execute
        ../../gcc/gcc/function.c:6630


Reduced testcase, crashes for gcc-5 and gcc-6:

markus@x4 tmp % cat tracesig.ii
struct {
  char msgdata[][8];
} __thread *mythread;
char *fn1() { return mythread->msgdata[1]; }

markus@x4 tmp % g++ -c -fPIC -mpreferred-stack-boundary=5
-mincoming-stack-boundary=4 tracesig.ii
tracesig.ii: In function ‘char* fn1()’:
tracesig.ii:4:44: internal compiler error: Segmentation fault
 char *fn1() { return mythread->msgdata[1]; }
                                            ^

0xcfb38f crash_signal
        ../../gcc/gcc/toplev.c:335
0x7f22485a914f ???
       
/home/markus/glibc/signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
0x1017c94 ix86_expand_prologue()
        ../../gcc/gcc/config/i386/i386.c:12751
0x11cf8ca gen_prologue()
        ../../gcc/gcc/config/i386/i386.md:12451
0xffed78 target_gen_prologue
        ../../gcc/gcc/config/i386/i386.md:18466
0xa5649f thread_prologue_and_epilogue_insns()
        ../../gcc/gcc/function.c:6037
0xa56f72 rest_of_handle_thread_prologue_and_epilogue
        ../../gcc/gcc/function.c:6588
0xa56f72 execute
        ../../gcc/gcc/function.c:6630
Please submit a full bug report,