Function (or more narrow) scope static variables (as well as others not
placed on the stack) should also not have any effect on the stack
alignment. I noticed the issue first with Linux'es dynamic_pr_debug()
construct using an 8-byte aligned sub-file-scope local variable.

According to my checking bad behavior started with 4.6.x (4.5.3 was
still okay), but generated code got quite a bit worse as of 4.9.0.

gcc/
2015-12-11  Jan Beulich  <jbeulich@suse.com>

	* cfgexpand.c (expand_one_var): Exit early for static and
	external variables when adjusting stack alignment related.

gcc/testsuite/
2015-12-11  Jan Beulich  <jbeulich@suse.com>

	* gcc.c-torture/execute/stkalign.c: New.

From-SVN: r231569