[Flang] how to link derf?

[ye-luo]

program ab
  implicit none
  real*8 a,b,derf
  b=2.d0
  a=derf(dsqrt(b))
end program

$ flang-new main.f90 
/usr/bin/ld: /tmp/main-3d7c8c.o: in function `_QQmain':
FIRModule:(.text+0x28): undefined reference to `derf_'
flang-new: error: linker command failed with exit code 1 (use -v to see invocation)

It seems to be a GNU extension but GNU/INTEL/NVFortran all work.

erf is available in libm so probably just need a wrapper?

[llvmbot]

@llvm/issue-subscribers-flang-runtime

Author: Ye Luo (ye-luo)

``` program ab implicit none real*8 a,b,derf b=2.d0 a=derf(dsqrt(b)) end program ``` ``` $ flang-new main.f90 /usr/bin/ld: /tmp/main-3d7c8c.o: in function `_QQmain': FIRModule:(.text+0x28): undefined reference to `derf_' flang-new: error: linker command failed with exit code 1 (use -v to see invocation) ``` It seems to be a GNU extension but GNU/INTEL/NVFortran all work.

erf is available in libm so probably just need a wrapper?

[jeffhammond]

Described as "archaic" in GCC 3.4.6 docs (https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/DErF-Intrinsic.html). I'm sure they'll fix the bug, but you should report this bug to the app and have them fix it too.

[ye-luo]

https://gcc.gnu.org/onlinedocs/gfortran/ERF.html
https://www.ibm.com/docs/en/xffbg/121.141?topic=procedures-erfx-fortran-2008
https://www.intel.com/content/www/us/en/docs/fortran-compiler/developer-guide-reference/2024-0/erf.html

@jeffhammond I don't get why you were talking about gcc 3.4.6 stuff.