[Bug tree-optimization/113049] New: Compiles to strlen even with -fno-builtin-strlen -fno-optimize-strlen

[gjl at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113049

            Bug ID: 113049
           Summary: Compiles to strlen even with -fno-builtin-strlen
                    -fno-optimize-strlen
           Product: gcc
           Version: 12.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gjl at gcc dot gnu.org
  Target Milestone: ---

Compile with -S -Os -fno-builtin-strlen -fno-optimize-strlen

typedef __SIZE_TYPE__ size_t;

size_t strlen (const char *text)
{
  size_t len = 0;

  while (*text)
  {
    text++;
    len++;
  }
  return len;

}

Generated code:

strlen:
        b       strlen


Using built-in specs.
COLLECT_GCC=/opt/compiler-explorer/arm/gcc-12.2.0/arm-unknown-linux-gnueabihf/bin/arm-unknown-linux-gnueabihf-gcc
Target: arm-unknown-linux-gnueabihf
Configured with: /opt/.build/arm-unknown-linux-gnueabihf/src/gcc/configure
--build=x86_64-build_pc-linux-gnu --host=x86_64-build_pc-linux-gnu
--target=arm-unknown-linux-gnueabihf
--prefix=/opt/compiler-explorer/arm/gcc-12.2.0/arm-unknown-linux-gnueabihf
--exec_prefix=/opt/compiler-explorer/arm/gcc-12.2.0/arm-unknown-linux-gnueabihf
--with-sysroot=/opt/compiler-explorer/arm/gcc-12.2.0/arm-unknown-linux-gnueabihf/arm-unknown-linux-gnueabihf/sysroot
--enable-languages=c,c++,fortran,d,objc,obj-c++,go --with-arch=armv7-a
--with-fpu=neon --with-float=hard --enable-__cxa_atexit --disable-libmudflap
--enable-libgomp --enable-libssp --enable-libquadmath
--enable-libquadmath-support --enable-libsanitizer --disable-libmpx
--with-gmp=/opt/.build/arm-unknown-linux-gnueabihf/buildtools
--with-mpfr=/opt/.build/arm-unknown-linux-gnueabihf/buildtools
--with-mpc=/opt/.build/arm-unknown-linux-gnueabihf/buildtools
--with-isl=/opt/.build/arm-unknown-linux-gnueabihf/buildtools --enable-lto
--enable-threads=posix --enable-target-optspace --disable-plugin --disable-nls
--enable-tls --disable-multilib
--with-local-prefix=/opt/compiler-explorer/arm/gcc-12.2.0/arm-unknown-linux-gnueabihf/arm-unknown-linux-gnueabihf/sysroot
--enable-long-long --with-mode=thumb
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.2.0 (GCC) 

https://godbolt.org/z/En3j6Gvda

Maybe this is same / similar to PR102725.