re PR middle-end/38454 (memcpy folding breaks -D_FORTIFY_SOURCE=2 protection)

re PR middle-end/38454 (memcpy folding breaks -D_FORTIFY_SOURCE=2 protection)

	PR middle-end/38454
	* function.h (struct function): Add always_inline_functions_inlined.
	* ipa-inline.c (cgraph_early_inlining): Set it to true.
	* tree-optimize.c (execute_fixup_cfg): Likewise.
	* builtins.c (avoid_folding_inline_builtin): New function.
	(fold_call_expr): Don't optimize always_inline builtins before
	inlining.
	(fold_call_stmt): Likewise.
	(fold_builtin_call_array): Likewise.  Don't call
	fold_builtin_varargs for BUILT_IN_MD builtins.

	* gcc.dg/memset-1.c: New test.
	* gcc.dg/memcpy-2.c: New test.

From-SVN: r142617