https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85923
--- Comment #7 from Sami Kantoluoto <sami.kantoluoto at embedtronics dot fi> ---
Yes, that seems to fix it:
.skipblk:
.LFB0:
movq _ctype_tab_ptr(%rip), %r8
xorl %eax, %eax
.L2:
movq (%rdi), %rdx
movq (%r8), %rsi
movzbl (%rdx), %ecx
testb $8, (%rsi,%rcx)
je .L5
incq %rdx
incl %eax
movq %rdx, (%rdi)
jmp .L2
.L5:
ret
