[Bug 1826820] Re: calling setjmp destruct a variable

[Paul White]

** Package changed: ubuntu => gcc-7 (Ubuntu)

** Tags removed: gcc
** Tags added: bionic

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Title:
  calling setjmp destruct a variable

Status in gcc-7 package in Ubuntu:
  New

Bug description:
  In Ubuntu 18.04 armhf with gcc-7, the following code, which compiles
  normally, gives incorrect result (on my machine, -964176505 instead of
  correct value 1).

  #include <setjmp.h>
  #include <stdio.h>

  jmp_buf a[10] ;
  jmp_buf * volatile sp = a ;

  int main()
  {
      if (setjmp(*sp++) == 0) {
  	printf("diff=%td\n", sp-a) ;
  	return 0 ;
      }
      return 1 ;
  }

  Additional information:
  The above code gives correct answer on Ubuntu 16.04 x86_64 gcc 5.4.
  If I replace '*sp++' with '*++sp', the program gives correct value 1.

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