[RFC][SLP] SLP vectorization: vectorize vector constructors

[Joel Hutton]

On 01/10/2019 12:07, Joel wrote:
>
> SLP vectorization: vectorize vector constructors
>
>
> Currently SLP vectorization can build SLP trees staring from 
> reductions or from group stores. This patch adds a third starting 
> point: vector constructors.
>
>
> For the following test case (compiled with -O3 -fno-vect-cost-model):
>
>
> char g_d[1024], g_s1[1024], g_s2[1024]; void test_loop(void) { char /d 
> = g_d, /s1 = g_s1, *s2 = g_s2;
>
>
> for ( int y = 0; y < 128; y++ )
> {
>    for ( int x = 0; x < 16; x++ )
>      d[x] = s1[x] + s2[x];
>    d += 16;
> }
>
> }
>
>
> before patch: test_loop: .LFB0: .cfi_startproc adrp x0, g_s1 adrp x2, 
> g_s2 add x3, x0, :lo12:g_s1 add x4, x2, :lo12:g_s2 ldrb w7, [x2, 
> #:lo12:g_s2] ldrb w1, [x0, #:lo12:g_s1] adrp x0, g_d ldrb w6, [x4, 1] 
> add x0, x0, :lo12:g_d ldrb w5, [x3, 1] add w1, w1, w7 fmov s0, w1 ldrb 
> w7, [x4, 2] add w5, w5, w6 ldrb w1, [x3, 2] ldrb w6, [x4, 3] add x2, 
> x0, 2048 ins v0.b[1], w5 add w1, w1, w7 ldrb w7, [x3, 3] ldrb w5, [x4, 
> 4] add w7, w7, w6 ldrb w6, [x3, 4] ins v0.b[2], w1 ldrb w8, [x4, 5] 
> add w6, w6, w5 ldrb w5, [x3, 5] ldrb w9, [x4, 6] add w5, w5, w8 ldrb 
> w1, [x3, 6] ins v0.b[3], w7 ldrb w8, [x4, 7] add w1, w1, w9 ldrb w11, 
> [x3, 7] ldrb w7, [x4, 8] add w11, w11, w8 ldrb w10, [x3, 8] ins 
> v0.b[4], w6 ldrb w8, [x4, 9] add w10, w10, w7 ldrb w9, [x3, 9] ldrb 
> w7, [x4, 10] add w9, w9, w8 ldrb w8, [x3, 10] ins v0.b[5], w5 ldrb w6, 
> [x4, 11] add w8, w8, w7 ldrb w7, [x3, 11] ldrb w5, [x4, 12] add w7, 
> w7, w6 ldrb w6, [x3, 12] ins v0.b[6], w1 ldrb w12, [x4, 13] add w6, 
> w6, w5 ldrb w5, [x3, 13] ldrb w1, [x3, 14] add w5, w5, w12 ldrb w13, 
> [x4, 14] ins v0.b[7], w11 ldrb w12, [x4, 15] add w4, w1, w13 ldrb w1, 
> [x3, 15] add w1, w1, w12 ins v0.b[8], w10 ins v0.b[9], w9 ins 
> v0.b[10], w8 ins v0.b[11], w7 ins v0.b[12], w6 ins v0.b[13], w5 ins 
> v0.b[14], w4 ins v0.b[15], w1 .p2align 3,,7 .L2: str q0, [x0], 16 cmp 
> x2, x0 bne .L2 ret .cfi_endproc .LFE0:
>
>
> After patch:
>
>
> test_loop: .LFB0: .cfi_startproc adrp x3, g_s1 adrp x2, g_s2 add x3, 
> x3, :lo12:g_s1 add x2, x2, :lo12:g_s2 adrp x0, g_d add x0, x0, 
> :lo12:g_d add x1, x0, 2048 ldr q1, [x2] ldr q0, [x3] add v0.16b, 
> v0.16b, v1.16b .p2align 3,,7 .L2: str q0, [x0], 16 cmp x0, x1 bne .L2 
> ret .cfi_endproc .LFE0:
>
>
>
>
> bootstrapped and tested on aarch64-none-linux-gnu
>
Patch attached:
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