[Bug c/77675] New: optimization level==number of -Wformat-length warnings

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77675

            Bug ID: 77675
           Summary: optimization level==number of -Wformat-length warnings
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: trippels at gcc dot gnu.org
  Target Milestone: ---

Created attachment 39666
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39666&action=edit
unreduced testcase

Consider the attached unreduced testcase. The number of redundant warnings
increases with the -O level due to inlining:

markus@x4 /tmp % gcc -O1 -c -Wformat-length algapi.i
crypto/algapi.c: In function ‘crypto_inst_setname’:
crypto/algapi.c:817:6: warning: output may be truncated at or before format
character ‘)’ at offset 5 [-Wformat-length=]
crypto/algapi.c:817:6: note: format output between 3 and 66 bytes into a
destination of size 64

markus@x4 /tmp % cc -O2 -c -Wformat-length algapi.i
crypto/algapi.c: In function ‘crypto_inst_setname’:
crypto/algapi.c:817:6: warning: output may be truncated at or before format
character ‘)’ at offset 5 [-Wformat-length=]
crypto/algapi.c:817:6: note: format output between 3 and 66 bytes into a
destination of size 64
crypto/algapi.c: In function ‘crypto_alloc_instance2’:
crypto/algapi.c:817:6: warning: output may be truncated at or before format
character ‘)’ at offset 5 [-Wformat-length=]
crypto/algapi.c:817:6: note: format output between 3 and 66 bytes into a
destination of size 64

markus@x4 /tmp % gcc -O3 -c -Wformat-length algapi.i
crypto/algapi.c: In function ‘crypto_inst_setname’:
crypto/algapi.c:817:6: warning: output may be truncated at or before format
character ‘)’ at offset 5 [-Wformat-length=]
crypto/algapi.c:817:6: note: format output between 3 and 66 bytes into a
destination of size 64
crypto/algapi.c: In function ‘crypto_alloc_instance2’:
crypto/algapi.c:817:6: warning: output may be truncated at or before format
character ‘)’ at offset 5 [-Wformat-length=]
crypto/algapi.c:817:6: note: format output between 3 and 66 bytes into a
destination of size 64
crypto/algapi.c: In function ‘crypto_alloc_instance’:
crypto/algapi.c:817:6: warning: output may be truncated at or before format
character ‘)’ at offset 5 [-Wformat-length=]
crypto/algapi.c:817:6: note: format output between 3 and 66 bytes into a
destination of size 64