* hooks.c (hook_tree_tree_identity): New.
	* hooks.h: Add a prototype for hook_tree_tree_identity.
	* stmt.c (expand_asm_operands): Use targetm.md_asm_clobbers
	instead of MD_ASM_CLOBBERS.
	* system.h (MD_ASM_CLOBBERS): Poison.
	* target-def.h (TARGET_MD_ASM_CLOBBERS): New.
	(TARGET_INITIALIZER): Add TARGET_MD_ASM_CLOBBERS.
	* target.h (gcc_target): Add md_asm_clobbers.
	* config/i386/i386.c (TARGET_MD_ASM_CLOBBERS): New.
	(ix86_md_asm_clobbers): New.
	* config/i386/i386.h (MD_ASM_CLOBBERS): Remove.
	* doc/tm.texi (MD_ASM_CLOBBERS): Change to
	TARGET_MD_ASM_CLOBBERS.

From-SVN: r78868