ivopts previously treated pointer arguments to internal functions
like IFN_MASK_LOAD and IFN_MASK_STORE as normal gimple values.
This patch makes it treat them as addresses instead.  This makes
a significant difference to the code quality for SVE loops,
since we can then use loads and stores with scaled indices.

2018-01-13  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* tree-ssa-loop-ivopts.c (USE_ADDRESS): Split into...
	(USE_REF_ADDRESS, USE_PTR_ADDRESS): ...these new use types.
	(dump_groups): Update accordingly.
	(iv_use::mem_type): New member variable.
	(address_p): New function.
	(record_use): Add a mem_type argument and initialize the new
	mem_type field.
	(record_group_use): Add a mem_type argument.  Use address_p.
	Remove obsolete null checks of base_object.  Update call to record_use.
	(find_interesting_uses_op): Update call to record_group_use.
	(find_interesting_uses_cond): Likewise.
	(find_interesting_uses_address): Likewise.
	(get_mem_type_for_internal_fn): New function.
	(find_address_like_use): Likewise.
	(find_interesting_uses_stmt): Try find_address_like_use before
	calling find_interesting_uses_op.
	(addr_offset_valid_p): Use the iv mem_type field as the type
	of the addressed memory.
	(add_autoinc_candidates): Likewise.
	(get_address_cost): Likewise.
	(split_small_address_groups_p): Use address_p.
	(split_address_groups): Likewise.
	(add_iv_candidate_for_use): Likewise.
	(autoinc_possible_for_pair): Likewise.
	(rewrite_groups): Likewise.
	(get_use_type): Check for USE_REF_ADDRESS instead of USE_ADDRESS.
	(determine_group_iv_cost): Update after split of USE_ADDRESS.
	(get_alias_ptr_type_for_ptr_address): New function.
	(rewrite_use_address): Rewrite address uses in calls that were
	identified by find_address_like_use.

gcc/testsuite/
	* gcc.dg/tree-ssa/scev-9.c: Expected REFERENCE ADDRESS
	instead of just ADDRESS.
	* gcc.dg/tree-ssa/scev-10.c: Likewise.
	* gcc.dg/tree-ssa/scev-11.c: Likewise.
	* gcc.dg/tree-ssa/scev-12.c: Likewise.
	* gcc.target/aarch64/sve/index_offset_1.c: New test.
	* gcc.target/aarch64/sve/index_offset_1_run.c: Likewise.
	* gcc.target/aarch64/sve/loop_add_2.c: Likewise.
	* gcc.target/aarch64/sve/loop_add_3.c: Likewise.
	* gcc.target/aarch64/sve/while_1.c: Check for indexed addressing modes.
	* gcc.target/aarch64/sve/while_2.c: Likewise.
	* gcc.target/aarch64/sve/while_3.c: Likewise.
	* gcc.target/aarch64/sve/while_4.c: Likewise.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r256628