Re: [RFC Patch], PowerPC memory support pre-gcc9, patch #3

[Michael Meissner <meissner at linux dot vnet dot ibm dot com>]

This patch moves the instructions for movdi (both 32-bit and 64-bit) into a
separate rs6000_output_move_64bit function.

As I'm starting to move more stuff to checking the addr_masks instead of doing
a lot of if mode == MODE1 || mode == MODE2, etc. I realized that the
mult-register types (complex values, long double using IBM double double, etc.)
did not have the offset bits set correctly in reg_addr.  I also prevented the
Altivec load/stores (that give you the free AND with -16) from being generated
for multi-register values.

I added a function (rs6000_valid_move_p) that replaces the old is operand[0] a
register or is operand[1] a register tests.  Right now, it generates the same
tests, but I may need to add additional conditions in the future.

I have done a full bootstrap and make check on a little endian power8 system
with no regressions.

The next patch will change the MOVDF and MOVDD patterns to use
rs6000_output_move_64bit as well.

2018-03-15  Michael Meissner  <meissner@linux.vnet.ibm.com>

	* config/rs6000/rs6000-protos.h (rs6000_output_move_64bit): Add
	declaration.
	(rs6000_valid_move_p): Likewise.
	* config/rs6000/rs6000-output.c (addr_is_xform_p): New helper
	function to return if an addresses uses X-form (reg+reg).
	(reg_is_spr_p): New helper function to determine if a register is
	a SPR.
	(rs6000_output_move_64bit): New function to return the proper
	instruction to do a 64-bit move.
	* config/rs6000/rs6000.c (rs6000_setup_reg_addr_masks): Rework
	setting offset addresses to assume multi-register values have the
	proper offset bits set.  Do not enable Altivec & -16 on
	mult-reigster moves.
	(rs6000_valid_move_p): New function to validate moves.
	(reg_offset_addressing_ok_p): Add check if the mode and register
	class support offstable instructions.
	* config/rs6000/rs6000.md (movdi_internal32): Move instruction
	literals to rs6000_otuput_move_64bit.  Check move validity with
	rs6000_move_valid_p.
	(movdi_internal64): Likewise.

-- 
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meissner@linux.vnet.ibm.com, phone: +1 (978) 899-4797

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