ira.c validate_equiv_mem

ira.c validate_equiv_mem

This function is used to validate REG_EQUIV notes generated by ira,
and to validate potential insn combines performed by ira.  The two
conditions are not exactly the same, with reload being more
restrictive.  Separate them so more combines/moves can occur.

For example, this sequence from cfgexpand.c:expand_gimple_cond
	callq  _Z18update_bb_for_insnP15basic_block_def
	mov    0x10(%rbx),%rdi
	mov    0x0(%rip),%rbp        # x_rtl+0x34
	callq  _Z9safe_as_aIP8rtx_insn7rtx_defET_PT0_
	mov    %r13,%rdx
	mov    %rbp,%rsi
	mov    %rax,%rdi
	callq  _Z18create_basic_blockP7rtx_defS0_P15basic_block_def

becomes
	callq  _Z18update_bb_for_insnP15basic_block_def
	mov    0x10(%rbx),%rdi
	callq  _Z9safe_as_aIP8rtx_insn7rtx_defET_PT0_
	mov    0x0(%rip),%rsi        # x_rtl+0x34
	mov    %r13,%rdx
	mov    %rax,%rdi
	callq  _Z18create_basic_blockP7rtx_defS0_P15basic_block_def

	* ira.c (enum valid_equiv): New.
	(validate_equiv_mem): Return enum.
	(update_equiv_mem): Create replacement in more cases.
	(add_store_equivs): Update validate_equiv_mem call.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@235661 138bc75d-0d04-0410-961f-82ee72b054a4