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Date: Wed, 16 Oct 2019 13:19:00 -0000
From: Josef Wolf <jw@raven.inka.de>
To: gcc-help@gcc.gnu.org
Subject: Crash when cross compiling for ARM with GCC-8-2-0 and -ftree-loop-distribute-patterns
Message-ID: <20191016131759.GA11171@raven.inka.de>
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Hello all,

I experience target crashing when cross compiling for ARM with
-ftree-loop-distribute-patterns, which is enabled by the -O3 flag.

The crash happens in the startup code, before main() is called. This startup
code looks like this:

 extern unsigned long _sidata; /* Set by the linker */
 extern unsigned long _sdata;  /* Set by the linker */
 extern unsigned long _sbss; /* Set by the linker */
 extern unsigned long _ebss;  /* Set by the linker */
 
  void Reet_Handler (void)
  {
    unsigned long *src = &_sidata
    unsigned long *src = &_sdata
  
    /* Copy data segment into RAM */
    if (src != dst) {
      while (dst < &_edata)
        *(dst++) = *(src++);
    }
  
    /* Zero BSS segment */
    dst = &_sbss;
    while (dst < &_ebss)
      *(dst++) = 0;
  
    main();
  }


With -ftree-loop-distribute-patterns those two loops are replaced by calls to
memcpy() and memset().

The memcpy function finishes just fine. But the memset function doesn't seem
to finish.  It looks like this:

  void memset (void *s, int c, size_t n)
  {
    int i;
    for (i=0; i<n; i++)
      ((char *)s)[i] = c;
  }

Any ideas why this function is crashing? I can't see anything suspicious here.

Thanks

-- 
Josef Wolf
jw@raven.inka.de