Spurious warnings when gcse is active.

[Klaus-Georg Adams <Klaus-Georg dot Adams at chemie dot uni-karlsruhe dot de>]

Hi Jeff,
The attached file produces spuriuos warnings which seem to indicate an
error somewhere in gcse.
The minimal set of flags to produce them is 
g++ -Wall -O -fgcse -frerun-loop-opt

They vanish if you change the program slightly (e.g. leave out the
enum, or replace "foo" by foo(), or leave out one of the lines... Very
strange). I have tried to boil this down as much as possible.

kga
-- 
-------------------------------------------------------------------------
Klaus-Georg Adams        Email: Klaus-Georg.Adams@chemie.uni-karlsruhe.de
Institut f. Anorg. Chemie, Lehrstuhl II            Tel: 49(0)721 608 3485
Universität Karlsruhe, D-76128 Karlsruhe
-------------------------------------------------------------------------

#include <string>
string foo();
struct a {
	void bar();
	enum b { c, d };
	b theb;
	string baz;
};

void
a::bar()
{
	baz += foo() + foo();
	baz += foo() + foo() + "foo";
}