[PATCH][GCC][AArch64] Vectorise __builtin_signbit on aarch64

[Przemyslaw Wirkus <Przemyslaw dot Wirkus at arm dot com>]

Hi all,

Vectorise __builtin_signbit (v4sf) with unsigned shift right vector
instruction.

Bootstrapped and tested on aarch64-none-linux-gnu.

Assembly output for:
$ aarch64-elf-gcc -S -O3 signbitv4sf.c -dp

Before patch:

foo:
	adrp	x3, in	// 37	[c=4 l=4]  *movdi_aarch64/12
	adrp	x2, out	// 40	[c=4 l=4]  *movdi_aarch64/12
	add	x3, x3, :lo12:in	// 39	[c=4 l=4]  add_losym_di
	add	x2, x2, :lo12:out	// 42	[c=4 l=4]  add_losym_di
	mov	x0, 0	// 3	[c=4 l=4]  *movdi_aarch64/3
	.p2align 3,,7
.L2:
	ldr	w1, [x3, x0]	// 10	[c=16 l=4]  *zero_extendsidi2_aarch64/1
	and	w1, w1, -2147483648	// 11	[c=4 l=4]  andsi3/1
	str	w1, [x2, x0]	// 16	[c=4 l=4]  *movsi_aarch64/8
	add	x0, x0, 4	// 17	[c=4 l=4]  *adddi3_aarch64/0
	cmp	x0, 4096	// 19	[c=4 l=4]  cmpdi/1
	bne	.L2		// 20	[c=4 l=4]  condjump
	ret		// 50	[c=0 l=4]  *do_return

After patch:

foo:
	adrp	x2, in	// 36	[c=4 l=4]  *movdi_aarch64/12
	adrp	x1, out	// 39	[c=4 l=4]  *movdi_aarch64/12
	add	x2, x2, :lo12:in	// 38	[c=4 l=4]  add_losym_di
	add	x1, x1, :lo12:out	// 41	[c=4 l=4]  add_losym_di
	mov	x0, 0	// 3	[c=4 l=4]  *movdi_aarch64/3
	.p2align 3,,7
.L2:
	ldr	q0, [x2, x0]	// 10	[c=8 l=4]  *aarch64_simd_movv4sf/0
	ushr	v0.4s, v0.4s, 31	// 11	[c=12 l=4]  aarch64_simd_lshrv4si
	str	q0, [x1, x0]	// 15	[c=4 l=4]  *aarch64_simd_movv4si/2
	add	x0, x0, 16	// 16	[c=4 l=4]  *adddi3_aarch64/0
	cmp	x0, 4096	// 18	[c=4 l=4]  cmpdi/1
	bne	.L2		// 19	[c=4 l=4]  condjump
	ret		// 49	[c=0 l=4]  *do_return

Thanks,
Przemyslaw

gcc/ChangeLog:

2019-03-20  Przemyslaw Wirkus  <przemyslaw.wirkus@arm.com>

	* config/aarch64/aarch64-builtins.c
	(aarch64_builtin_vectorized_function): Added CASE_CFN_SIGNBIT.
	* config/aarch64/aarch64-simd-builtins.def: (signbit)
	Extend to V4SF mode.
	* config/aarch64/aarch64-simd.md (signbitv4sf2): New expand
	defined.

gcc/testsuite/ChangeLog:

2019-02-28  Przemyslaw Wirkus  <przemyslaw.wirkus@arm.com>

	* gcc.target/aarch64/signbitv4sf.c: New test.

Attachment: patch.txt
Description: patch.txt