https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108552
--- Comment #13 from Uroš Bizjak <ubizjak at gmail dot com> --- -fverbose-asm annotated assembly: prep_compound_page: pushl %ebp # movl %esp, %ebp #, pushl %edi # movl %eax, %edi # tmp356, page pushl %esi # pushl %ebx # subl $20, %esp #, cmpl $31, %edx #, order movl %edx, -28(%ebp) # order, %sfp ja .L1483 #, .L1464: movzbl -28(%ebp), %ecx # %sfp, tmp365 movl $1, %ebx #, tmp182 sall %cl, %ebx # tmp365, nr_pages cmpl $-1, (%edi) #, MEM[(const struct page *)page_12(D)].flags je .L1486 #, addl $1, __gcov0.prep_compound_page+16 #, __gcov0.prep_compound_page[2] adcl $0, __gcov0.prep_compound_page+20 #, __gcov0.prep_compound_page[2] #APP # 68 "./arch/x86/include/asm/bitops.h" 1 btsl $16,(%edi) #, MEM[(volatile long int *)_19] # 0 "" 2 #NO_APP addl $1, __gcov0.prep_compound_page+48 #, __gcov0.prep_compound_page[6] adcl $0, __gcov0.prep_compound_page+52 #, __gcov0.prep_compound_page[6] cmpl $1, %ebx #, nr_pages jle .L1470 #, leal 1(%edi), %eax #, _159 movl __gcov0.prep_compound_page+60, %edx # __gcov0.prep_compound_page[7], ivtmp.1714 movl %eax, -24(%ebp) # _159, %sfp movl __gcov0.prep_compound_page+56, %eax # __gcov0.prep_compound_page[7], ivtmp.1714 leal 40(%edi), %ecx #, ivtmp.1720 movl %edi, -32(%ebp) # page, %sfp addl $1, %eax #, ivtmp.1714 movl %eax, -20(%ebp) # ivtmp.1714, %sfp adcl $0, %edx #, ivtmp.1714 movl __gcov0.prep_compound_page+56, %eax # __gcov0.prep_compound_page[7], tmp228 movl %edx, -16(%ebp) # ivtmp.1714, %sfp movl __gcov0.prep_compound_page+60, %edx # __gcov0.prep_compound_page[7], subl $2, %ebx #, tmp226 xorl %esi, %esi # addl $2, %eax #, tmp228 adcl $0, %edx #, addl %eax, %ebx # tmp228, tmp227 movl -20(%ebp), %eax # %sfp, ivtmp.1714 adcl %edx, %esi #, movl -16(%ebp), %edx # %sfp, ivtmp.1714 movl %esi, %edi # _45, _45 movl %ebx, %esi # _45, _45 .p2align 4 .p2align 3 .L1469: movl %eax, __gcov0.prep_compound_page+56 # ivtmp.1714, __gcov0.prep_compound_page[7] movl -24(%ebp), %ebx # %sfp, _159 addl $1, %eax #, ivtmp.1714 movl %edx, __gcov0.prep_compound_page+60 # ivtmp.1714, __gcov0.prep_compound_page[7] adcl $0, %edx #, ivtmp.1714 addl $40, %ecx #, ivtmp.1720 movl $1024, -28(%ecx) #, MEM <struct address_space *> [(union *)p_15 + 12B] movl %ebx, -36(%ecx) # _159, MEM[(volatile long unsigned int *)p_15 + 4B] movl %edi, %ebx # _45, tmp230 xorl %edx, %ebx # ivtmp.1714, tmp230 movl %ebx, -20(%ebp) # tmp230, %sfp movl %esi, %ebx # _45, tmp231 xorl %eax, %ebx # ivtmp.1714, tmp231 orl -20(%ebp), %ebx # %sfp, tmp358 jne .L1469 #, movl -32(%ebp), %edi # %sfp, page .L1470: movb $1, 48(%edi) #, MEM[(struct page *)page_12(D) + 40B].D.13727.D.13705.compound_dtor ...