[parrot/parrot] c99023: imcc: fix exceptions in constant folding

[GitHub]

  Branch: refs/heads/smoke-me/const-exc-gh1236
  Home:   https://github.com/parrot/parrot
  Commit: c9902370d83c8c585cf1d0564a1630f518f53355
      https://github.com/parrot/parrot/commit/c9902370d83c8c585cf1d0564a1630f518f53355
  Author: Reini Urban <rurban at cpan.org>
  Date:   2017-06-06 (Tue, 06 Jun 2017)

  Changed paths:
    M compilers/imcc/optimizer.c
    M src/string/namealias.c
    M t/compilers/imcc/syn/const.t

  Log Message:
  -----------
  imcc: fix exceptions in constant folding

When an op with only constants args throws an exception like div by zero,
also return -1, not just on setjmp(current_runloop->resume)

Fixes #1236