xtensa: Fix up unwanted spills of SFmode hard registers holding function arguments/returnsHEADtrunkmaster

Until now (presumably after transition to LRA), hard registers storing
function arguments or return values ​​were spilling undesirably when
TARGET_HARD_FLOAT is enabled.

     /* example */
     float test0(float a, float b) {
       return a + b;
     }
     extern float foo(void);
     float test1(void) {
       return foo() * 3.14f;
     }

     ;; before
     test0:
     	entry	sp, 48
     	wfr	f0, a2
     	wfr	f1, a3
     	add.s	f0, f0, f1
     	s32i.n	a2, sp, 0	;; unwanted spilling-out
     	s32i.n	a3, sp, 4	;;
     	rfr	a2, f0
     	retw.n
     	.literal .LC1, 1078523331
     test1:
     	entry	sp, 48
     	call8	foo
     	l32r	a8, .LC1
     	wfr	f0, a10
     	wfr	f1, a8
     	mul.s	f0, f0, f1
     	s32i.n	a10, sp, 0	;; unwanted spilling-out
     	rfr	a2, f0
     	retw.n

Ultimately, that is because the costs of moving between integer and
floating-point hard registers are undefined and the default (large value)
is used.  This patch fixes this.

     ;; after
     test0:
     	entry	sp, 32
     	wfr	f1, a2
     	wfr	f0, a3
     	add.s	f0, f1, f0
     	rfr	a2, f0
     	retw.n
     	.literal .LC1, 1078523331
     test1:
     	entry	sp, 32
     	call8	foo
     	l32r	a8, .LC1
     	wfr	f1, a10
     	wfr	f0, a8
     	mul.s	f0, f1, f0
     	rfr	a2, f0
     	retw.n

gcc/ChangeLog:

	* config/xtensa/xtensa.cc (xtensa_register_move_cost):
	Add appropriate move costs between AR_REGS and FP_REGS.

0 files changed, 0 insertions, 0 deletions