alpha: Introduce target specific store_data_bypass_p function [PR105209]

alpha: Introduce target specific store_data_bypass_p function [PR105209]

This patch introduces alpha-specific version of store_data_bypass_p that
ignores TRAP_IF that would result in assertion failure (and internal
compiler error) in the generic store_data_bypass_p function.

While at it, also remove ev4_ist_c reservation, store_data_bypass_p
can handle the patterns with multiple sets since some time ago.

2022-06-17  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:

	PR target/105209
	* config/alpha/alpha-protos.h (alpha_store_data_bypass_p): New.
	* config/alpha/alpha.cc (alpha_store_data_bypass_p): New function.
	(alpha_store_data_bypass_p_1): Ditto.
	* config/alpha/ev4.md: Use alpha_store_data_bypass_p instead
	of generic store_data_bypass_p.
	(ev4_ist_c): Remove insn reservation.

gcc/testsuite/ChangeLog:

	PR target/105209
	* gcc.target/alpha/pr105209.c: New test.

(cherry picked from commit cc378e655740e93743e7f43e14faaff707aef6c1)