Fix PR49876: Continue code generation with integer_zero_node on gloog_error

Fix PR49876: Continue code generation with integer_zero_node on gloog_error

When setting gloog_error, graphite should continue code generation
without early returns, as otherwise the SSA representation would not
be complete.  So set the new expression to integer_zero_node, that
would not require more SSA updates, and continue code generation as
nothing happened.

Regstrapped on amd64-linux.

2011-07-28  Sebastian Pop  <sebastian.pop@amd.com>

	PR tree-optimization/49876
	* sese.c (rename_uses): Do not return false on gloog_error: set
	the new_expr to integer_zero_node and continue code generation.
	(graphite_copy_stmts_from_block): Remove early exit on gloog_error.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@176900 138bc75d-0d04-0410-961f-82ee72b054a4