re PR rtl-optimization/84101 (-O3 and -ftree-vectorize trying too hard for function returning trivial pair-of-uint64_t-structure)

2019-04-03  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/84101
	* tree-vect-stmts.c: Include explow.h for hard_function_value,
	regs.h for hard_regno_nregs.
	(cfun_returns): New helper.
	(vect_model_store_cost): When vectorizing a store to a decl
	we return and the function ABI returns in a multi-reg location
	account for the possible spilling that will happen.

	* gcc.target/i386/pr84101.c: New testcase.

From-SVN: r270123