PR tree-optimization/78257 - missing memcmp optimization with constant arrays

PR tree-optimization/78257 - missing memcmp optimization with constant arrays

gcc/ChangeLog:

	PR middle-end/78257
	* builtins.c (expand_builtin_memory_copy_args): Rename called function.
	(expand_builtin_stpcpy_1): Remove argument from call.
	(expand_builtin_memcmp): Rename called function.
	(inline_expand_builtin_bytecmp): Same.
	* expr.c (convert_to_bytes): New function.
	(constant_byte_string): New function (formerly string_constant).
	(string_constant): Call constant_byte_string.
	(byte_representation): New function.
	* expr.h (byte_representation): Declare.
	* fold-const-call.c (fold_const_call): Rename called function.
	* fold-const.c (c_getstr): Remove an argument.
	(getbyterep): Define a new function.
	* fold-const.h (c_getstr): Remove an argument.
	(getbyterep): Declare a new function.
	* gimple-fold.c (gimple_fold_builtin_memory_op): Rename callee.
	(gimple_fold_builtin_string_compare): Same.
	(gimple_fold_builtin_memchr): Same.

gcc/testsuite/ChangeLog:

	PR middle-end/78257
	* gcc.dg/memchr.c: New test.
	* gcc.dg/memcmp-2.c: New test.
	* gcc.dg/memcmp-3.c: New test.
	* gcc.dg/memcmp-4.c: New test.