https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97445
Bug ID: 97445 Summary: Some fonctions marked static inline in Linux kernel are not inlined Product: gcc Version: 10.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: christophe.leroy at csgroup dot eu Target Milestone: --- Some functions declared 'static inline' in Linux kernel sources are not inlined and are seen multiple times in the vmlinux binary. Two exemple: get_order() and csum_partial(): static inline __attribute_const__ int get_order(unsigned long size) { if (__builtin_constant_p(size)) { if (!size) return BITS_PER_LONG - PAGE_SHIFT; if (size < (1UL << PAGE_SHIFT)) return 0; return ilog2((size) - 1) - PAGE_SHIFT + 1; } size--; size >>= PAGE_SHIFT; #if BITS_PER_LONG == 32 return fls(size); #else return fls64(size); #endif } I get 75 times the following code: c0016790 <get_order>: c0016790: 38 63 ff ff addi r3,r3,-1 c0016794: 54 63 a3 3e rlwinm r3,r3,20,12,31 c0016798: 7c 63 00 34 cntlzw r3,r3 c001679c: 20 63 00 20 subfic r3,r3,32 c00167a0: 4e 80 00 20 blr static inline __wsum csum_partial(const void *buff, int len, __wsum sum) { if (__builtin_constant_p(len) && len <= 16 && (len & 1) == 0) { if (len == 2) sum = csum_add(sum, (__force __wsum)*(const u16 *)buff); if (len >= 4) sum = csum_add(sum, (__force __wsum)*(const u32 *)buff); if (len == 6) sum = csum_add(sum, (__force __wsum) *(const u16 *)(buff + 4)); if (len >= 8) sum = csum_add(sum, (__force __wsum) *(const u32 *)(buff + 4)); if (len == 10) sum = csum_add(sum, (__force __wsum) *(const u16 *)(buff + 8)); if (len >= 12) sum = csum_add(sum, (__force __wsum) *(const u32 *)(buff + 8)); if (len == 14) sum = csum_add(sum, (__force __wsum) *(const u16 *)(buff + 12)); if (len >= 16) sum = csum_add(sum, (__force __wsum) *(const u32 *)(buff + 12)); } else if (__builtin_constant_p(len) && (len & 3) == 0) { sum = csum_add(sum, ip_fast_csum_nofold(buff, len >> 2)); } else { sum = __csum_partial(buff, len, sum); } return sum; } ppc-linux-objdump -d vmlinux | grep -e "<csum_partial>" -e "<__csum_partial>" With gcc9 I get: c0017ef8 <__csum_partial>: c00182fc: 4b ff fb fd bl c0017ef8 <__csum_partial> c0018478: 4b ff fa 80 b c0017ef8 <__csum_partial> c03e8458: 4b c2 fa a0 b c0017ef8 <__csum_partial> c03e8518: 4b c2 f9 e1 bl c0017ef8 <__csum_partial> c03ef410: 4b c2 8a e9 bl c0017ef8 <__csum_partial> c03f0b24: 4b c2 73 d5 bl c0017ef8 <__csum_partial> c04279a4: 4b bf 05 55 bl c0017ef8 <__csum_partial> c0429820: 4b be e6 d9 bl c0017ef8 <__csum_partial> c0429944: 4b be e5 b5 bl c0017ef8 <__csum_partial> c042b478: 4b be ca 81 bl c0017ef8 <__csum_partial> c042b554: 4b be c9 a5 bl c0017ef8 <__csum_partial> c045f15c: 4b bb 8d 9d bl c0017ef8 <__csum_partial> c0492190: 4b b8 5d 69 bl c0017ef8 <__csum_partial> c0492310: 4b b8 5b e9 bl c0017ef8 <__csum_partial> c0495594: 4b b8 29 65 bl c0017ef8 <__csum_partial> c049c420: 4b b7 ba d9 bl c0017ef8 <__csum_partial> c049c870: 4b b7 b6 89 bl c0017ef8 <__csum_partial> c049c930: 4b b7 b5 c9 bl c0017ef8 <__csum_partial> c04a9ca0: 4b b6 e2 59 bl c0017ef8 <__csum_partial> c04bdde4: 4b b5 a1 15 bl c0017ef8 <__csum_partial> c04be480: 4b b5 9a 79 bl c0017ef8 <__csum_partial> c04be710: 4b b5 97 e9 bl c0017ef8 <__csum_partial> c04c969c: 4b b4 e8 5d bl c0017ef8 <__csum_partial> c04ca2fc: 4b b4 db fd bl c0017ef8 <__csum_partial> c04cf5bc: 4b b4 89 3d bl c0017ef8 <__csum_partial> c04d0440: 4b b4 7a b9 bl c0017ef8 <__csum_partial> With gcc10 I get: c0018d08 <__csum_partial>: c0019020 <csum_partial>: c0019020: 4b ff fc e8 b c0018d08 <__csum_partial> c001914c: 4b ff fe d4 b c0019020 <csum_partial> c0019250: 4b ff fd d1 bl c0019020 <csum_partial> c03e404c <csum_partial>: c03e404c: 4b c3 4c bc b c0018d08 <__csum_partial> c03e4050: 4b ff ff fc b c03e404c <csum_partial> c03e40fc: 4b ff ff 51 bl c03e404c <csum_partial> c03e6680: 4b ff d9 cd bl c03e404c <csum_partial> c03e68c4: 4b ff d7 89 bl c03e404c <csum_partial> c03e7934: 4b ff c7 19 bl c03e404c <csum_partial> c03e7bf8: 4b ff c4 55 bl c03e404c <csum_partial> c03eb148: 4b ff 8f 05 bl c03e404c <csum_partial> c03ecf68: 4b c2 bd a1 bl c0018d08 <__csum_partial> c04275b8 <csum_partial>: c04275b8: 4b bf 17 50 b c0018d08 <__csum_partial> c0427884: 4b ff fd 35 bl c04275b8 <csum_partial> c0427b18: 4b ff fa a1 bl c04275b8 <csum_partial> c0427bd8: 4b ff f9 e1 bl c04275b8 <csum_partial> c0427cd4: 4b ff f8 e5 bl c04275b8 <csum_partial> c0427e34: 4b ff f7 85 bl c04275b8 <csum_partial> c045a1c0: 4b bb eb 49 bl c0018d08 <__csum_partial> c0489464 <csum_partial>: c0489464: 4b b8 f8 a4 b c0018d08 <__csum_partial> c04896b0: 4b ff fd b5 bl c0489464 <csum_partial> c048982c: 4b ff fc 39 bl c0489464 <csum_partial> c0490158: 4b b8 8b b1 bl c0018d08 <__csum_partial> c0492f0c <csum_partial>: c0492f0c: 4b b8 5d fc b c0018d08 <__csum_partial> c049326c: 4b ff fc a1 bl c0492f0c <csum_partial> c049333c: 4b ff fb d1 bl c0492f0c <csum_partial> c0493b18: 4b ff f3 f5 bl c0492f0c <csum_partial> c0493f50: 4b ff ef bd bl c0492f0c <csum_partial> c0493ffc: 4b ff ef 11 bl c0492f0c <csum_partial> c04a0f78: 4b b7 7d 91 bl c0018d08 <__csum_partial> c04b3e3c: 4b b6 4e cd bl c0018d08 <__csum_partial> c04b40d0 <csum_partial>: c04b40d0: 4b b6 4c 38 b c0018d08 <__csum_partial> c04b4448: 4b ff fc 89 bl c04b40d0 <csum_partial> c04b46f4: 4b ff f9 dd bl c04b40d0 <csum_partial> c04bf448: 4b b5 98 c0 b c0018d08 <__csum_partial> c04c5264: 4b b5 3a a5 bl c0018d08 <__csum_partial> c04c61e4: 4b b5 2b 25 bl c0018d08 <__csum_partial> gcc10 defines multiple versions of csum_partial() which are just an unconditionnal branch to __csum_partial().