* stmt.c (expand_expr_stmt): Keep last_expr_value non-NULL iff

* stmt.c (expand_expr_stmt): Keep last_expr_value non-NULL iff
we're interested in the result.  Use it to tell whether to
ignore results of enclosed expressions.
(expand_start_stmt_expr): Added new argument, and initialize
last_expr_value accordingly.
* tree.h (expand_start_stmt_expr): Adjusted declaration.
* c-common.c (c_expand_expr): Adjust call.
* expr.c (expand_expr) [EXPR_WFL]: Pass const0_rtx down if
ignoring the result.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@47607 138bc75d-0d04-0410-961f-82ee72b054a4