[aarch64-port-dev ] RFR(S): 8243597: AArch64: Add support for integer vector abs

[Andrew Haley]

On 18/05/2020 06:51, Yang Zhang wrote:
> Testing:
> Full jtreg test
> Vector API tests which cover vector abs
> 
> Test case:
>   public static void absvs(short[] a, short[] b, short[] c) {
>       for (int i = 0; i < a.length; i++) {
>           c[i] = (short)Math.abs((a[i] + b[i]));
>       }
>   }
> 
> Assembly code generated by C2:
>   0x0000ffffaca3f3ac:   ldr	q17, [x16, #16]
>   0x0000ffffaca3f3b0:   ldr	q16, [x15, #16]
>   0x0000ffffaca3f3b4:   add	v16.8h, v16.8h, v17.8h
>   0x0000ffffaca3f3b8:   abs	v16.8h, v16.8h
>   0x0000ffffaca3f3c0:   str	q16, [x12, #16]
> 
> Similar test cases for byte/int/long are also tested and NEON abs instruction is generated by C2.

Unfortunately the test cases you provided do not include the method
absvs(short).

I'm not seeing this result. All I get with your patch applied in
the case of your test TestScalar

  @Benchmark
  public void testAbsI() {
     for (int n = 0; n < LOOP_CNT; n++) {
         for (int i = 0; i < ia.length; i += 4) {
             ic[i] = Math.abs(ia[i] + ib[i]);
         }
     }
  }

is

;; B18: #	out( B18 B19 ) <- in( B17 B18 ) Loop( B18-B18 inner main of N82 strip mined) Freq: 9.69583e+08
  0x0000ffff78824da0:   sbfiz	x11, x4, #2, #32
  0x0000ffff78824da4:   add	x7, x0, x11                 ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                            ; - org.openjdk.TestScalar::testAbsI at 36 (line 44)
  0x0000ffff78824da8:   add	xmethod, x18, x11           ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                            ; - org.openjdk.TestScalar::testAbsI at 30 (line 44)
  0x0000ffff78824dac:   ldr	w2, [x7,#16]
  0x0000ffff78824db0:   ldr	w13, [xmethod,#16]
  0x0000ffff78824db4:   add	w13, w13, w2
  0x0000ffff78824db8:   cmp	w13, wzr
  0x0000ffff78824dbc:   cneg	w1, w13, lt
  0x0000ffff78824dc0:   add	x11, x3, x11
  0x0000ffff78824dc4:   str	w1, [x11,#16]
  0x0000ffff78824dc8:   ldr	w2, [x7,#32]
  0x0000ffff78824dcc:   ldr	w1, [xmethod,#32]
  0x0000ffff78824dd0:   add	w13, w1, w2
  0x0000ffff78824dd4:   cmp	w13, wzr
  0x0000ffff78824dd8:   cneg	w1, w13, lt
  0x0000ffff78824ddc:   str	w1, [x11,#32]
  0x0000ffff78824de0:   ldr	w13, [x7,#48]
  0x0000ffff78824de4:   ldr	w1, [xmethod,#48]
  0x0000ffff78824de8:   add	w1, w1, w13
  0x0000ffff78824dec:   cmp	w1, wzr
  0x0000ffff78824df0:   cneg	w13, w1, lt
  0x0000ffff78824df4:   str	w13, [x11,#48]              ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                            ; - org.openjdk.TestScalar::testAbsI at 41 (line 44)
  0x0000ffff78824df8:   ldr	w1, [x7,#64]
  0x0000ffff78824dfc:   ldr	w12, [xmethod,#64]
  0x0000ffff78824e00:   add	w12, w12, w1
  0x0000ffff78824e04:   cmp	w12, wzr
  0x0000ffff78824e08:   cneg	w13, w12, lt
  0x0000ffff78824e0c:   add	w4, w4, #0x10               ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                            ; - org.openjdk.TestScalar::testAbsI at 42 (line 43)
  0x0000ffff78824e10:   str	w13, [x11,#64]              ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                            ; - org.openjdk.TestScalar::testAbsI at 41 (line 44)
  0x0000ffff78824e14:   cmp	w4, w6
  0x0000ffff78824e18:   b.lt	0x0000ffff78824da0          ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                            ; - org.openjdk.TestScalar::testAbsI at 17 (line 43)

Please provide me with a Java program that reproduces the result
above, thanks.

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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