[pr82089] Don't sign-extend SFV 1 in BImode

[pr82089] Don't sign-extend SFV 1 in BImode

This is an update of the patch posted to PR82089 long ago.  We ran into the
same bug on GCN, so we need this fixed as part of this series.

2018-09-27  Andrew Stubbs  <ams@codesourcery.com>
            Tom de Vries  <tom@codesourcery.com>

	PR 82089

	gcc/
	* expmed.c (emit_cstore): Fix handling of result_mode == BImode and
	STORE_FLAG_VALUE == 1.

Co-Authored-By: Tom de Vries <tom@codesourcery.com>
From-SVN: r264666