LoongArch: Tweak IOR rtx_cost for bstrins

Consider

    c &= 0xfff;
    a &= ~0xfff;
    b &= ~0xfff;
    a |= c;
    b |= c;

This can be done with 2 bstrins instructions.  But we need to recognize
it in loongarch_rtx_costs or the compiler will not propagate "c & 0xfff"
forward.

gcc/ChangeLog:

	* config/loongarch/loongarch.cc:
	(loongarch_use_bstrins_for_ior_with_mask): Split the main logic
	into ...
	(loongarch_use_bstrins_for_ior_with_mask_1): ... here.
	(loongarch_rtx_costs): Special case for IOR those can be
	implemented with bstrins.

gcc/testsuite/ChangeLog;

	* gcc.target/loongarch/bstrins-3.c: New test.

0 files changed, 0 insertions, 0 deletions