; RUN: %ProtectFileCheckOutput not FileCheck -check-prefix=CHECK-BACKREF %s < /dev/null 2>&1 | FileCheck -check-prefix=ERR-CHECK-BACKREF %s

; ERR-CHECK-BACKREF: error: Can't back-reference more than 20 variables

r0 r1 r2 r3 r4 r5 r6 r7 r8 r9 r10 r11 r12 r13 r14 r15 r16 r17 r18 r19 r20 r21

; CHECK-BACKREF: [[REG1:r0]] [[REG2:r1]] [[REG3:r2]] [[REG4:r3]] [[REG5:r4]] [[REG6:r5]] [[REG7:r6]] [[REG8:r7]] [[REG9:r8]] [[REG10:r9]] [[REG11:r10]] [[REG12:r11]] [[REG13:r12]] [[REG14:r13]] [[REG15:r14]] [[REG16:r15]] [[REG17:r16]] [[REG18:r17]] [[REG19:r18]] [[REG20:r19]] [[REG21:r20]] [[REG21]]