[LLD][ELF][AArch64] Increase test coverage of AArch64ErrataFix [NFC]

[peter.smith]

Summary

In the recognise test convert some ST1 multiple structure to ST1 single structure to test the isST1SingleOpcode() function. This was found to be uncovered in a recent code coverage report.

I had thought I had covered the ST1 single structure form by putting just one register in the argument list (st1 {v0.16b}, [x1], x2), however it turns out that I needed to use a different syntax (st1 {v0.b}[1], [x1], x2).

[ruiu]

LGTM

lld/trunk/test/ELF/aarch64-cortex-a53-843419-recognize.s

t3_ffc_stnp:
         adrp x7, dat1
         stnp x1,x2, [x3, #0]
         ldr x9, [x7, :lo12:dat1]
         ret
 
 // CHECK-PRINT: detected cortex-a53-843419 erratum sequence starting at 3BFFC in unpatched output.
 // CHECK: t3_ffc_st1singlepost:
 // CHECK-NEXT:    3bffc:        37 01 00 b0     adrp    x23, #151552
-// CHECK-NEXT:    3c000:        20 70 82 4c     st1     { v0.16b }, [x1], x2
+// CHECK-NEXT:    3c000:        20 04 82 0d     st1 { v0.b }[1], [x1], x2
 // CHECK-FIX:     3c004:        1c 50 00 14     b       #82032
 // CHECK-NOFIX:   3c004:        f6 06 40 f9     ldr     x22, [x23, #8]
 // CHECK-NEXT:    3c008:        c0 03 5f d6     ret
         .section .text.14, "ax", %progbits
         .balign 4096
         .globl t3_ffc_st1singlepost
         .type t3_ffc_st1singlepost, %function
         .space 4096 - 4
 t3_ffc_st1singlepost:
         adrp x23, dat2
-        st1 { v0.16b }, [x1], x2
+        st1 { v0.b }[1], [x1], x2
         ldr x22, [x23, :lo12:dat2]
         ret
 
 // CHECK-PRINT: detected cortex-a53-843419 erratum sequence starting at 3DFF8 in unpatched output.
 // CHECK: t3_ff8_st1multiple:
 // CHECK-NEXT:    3dff8:        17 01 00 f0     adrp    x23, #143360
 // CHECK-NEXT:    3dffc:        20 a0 00 4c     st1     { v0.16b, v1.16b }, [x1]
 // CHECK-FIX:     3e000:        1f 48 00 14     b       #73852
t4_ffc_stnp:
         stnp x1,x2, [x3, #0]
         nop
         ldr x10, [x7, :got_lo12:dat1]
         ret
 
 // CHECK-PRINT: detected cortex-a53-843419 erratum sequence starting at 4DFFC in unpatched output.
 // CHECK: t4_ffc_st1:
 // CHECK-NEXT:    4dffc:        98 00 00 f0     adrp    x24, #77824
-// CHECK-NEXT:    4e000:        20 70 00 4c     st1     { v0.16b }, [x1]
+// CHECK-NEXT:    4e000:        20 80 00 4d     st1 { v0.s }[2], [x1]
 // CHECK-NEXT:    4e004:        f6 06 40 f9     ldr     x22, [x23, #8]
 // CHECK-FIX:     4e008:        2d 08 00 14     b       #8372
 // CHECK-NOFIX:   4e008:        18 ff 3f f9     str     x24, [x24, #32760]
 // CHECK-NEXT:    4e00c:        c0 03 5f d6     ret
         .section .text.23, "ax", %progbits
         .balign 4096
         .globl t4_ffc_st1
         .type t4_ffc_st1, %function
         .space 4096 - 4
 t4_ffc_st1:
         adrp x24, dat2
-        st1 { v0.16b }, [x1]
+        st1 { v0.s }[2], [x1]
         ldr x22, [x23, :got_lo12:dat2]
         str x24, [x24, #32760]
         ret
 
 // CHECK-PRINT: detected cortex-a53-843419 erratum sequence starting at 4FFF8 in unpatched output.
 // CHECK: t3_ff8_ldr_once:
 // CHECK-NEXT:    4fff8:        80 00 00 b0     adrp    x0, #69632
 // CHECK-NEXT:    4fffc:        20 70 82 4c     st1     { v0.16b }, [x1], x2