3 files changed, 10 insertions, 5 deletions
diff --git a/numpy/distutils/fcompiler/__init__.py b/numpy/distutils/fcompiler/__init__.py
index ecba3e5d5..5160e2abf 100644
--- a/numpy/distutils/fcompiler/__init__.py
+++ b/numpy/distutils/fcompiler/__init__.py
@@ -19,6 +19,7 @@ __all__ = ['FCompiler', 'new_fcompiler', 'show_fcompilers',
 import os
 import sys
 import re
+from pathlib import Path
 
 from distutils.sysconfig import get_python_lib
 from distutils.fancy_getopt import FancyGetopt
@@ -37,6 +38,10 @@ from .environment import EnvironmentConfig
 
 __metaclass__ = type
 
+
+FORTRAN_COMMON_FIXED_EXTENSIONS = ['.for', '.ftn', '.f77', '.f']
+
+
 class CompilerNotFound(Exception):
     pass
 
@@ -571,7 +576,8 @@ class FCompiler(CCompiler):
     def _compile(self, obj, src, ext, cc_args, extra_postargs, pp_opts):
         """Compile 'src' to product 'obj'."""
         src_flags = {}
-        if is_f_file(src) and not has_f90_header(src):
+        if Path(src).suffix.lower() in FORTRAN_COMMON_FIXED_EXTENSIONS \
+           and not has_f90_header(src):
             flavor = ':f77'
             compiler = self.compiler_f77
             src_flags = get_f77flags(src)
@@ -970,7 +976,6 @@ def dummy_fortran_file():
     return name[:-2]
 
 
-is_f_file = re.compile(r'.*\.(for|ftn|f77|f)\Z', re.I).match
 _has_f_header = re.compile(r'-\*-\s*fortran\s*-\*-', re.I).search
 _has_f90_header = re.compile(r'-\*-\s*f90\s*-\*-', re.I).search
 _has_fix_header = re.compile(r'-\*-\s*fix\s*-\*-', re.I).search
diff --git a/numpy/distutils/fcompiler/absoft.py b/numpy/distutils/fcompiler/absoft.py
index efe3a4cb5..68f516b92 100644
--- a/numpy/distutils/fcompiler/absoft.py
+++ b/numpy/distutils/fcompiler/absoft.py
@@ -1,6 +1,6 @@
 
-# http://www.absoft.com/literature/osxuserguide.pdf
-# http://www.absoft.com/documentation.html
+# Absoft Corporation ceased operations on 12/31/2022.
+# Thus, all links to <http://www.absoft.com> are invalid.
 
 # Notes:
 # - when using -g77 then use -DUNDERSCORE_G77 to compile f2py
diff --git a/numpy/distutils/fcompiler/ibm.py b/numpy/distutils/fcompiler/ibm.py
index eff24401a..29927518c 100644
--- a/numpy/distutils/fcompiler/ibm.py
+++ b/numpy/distutils/fcompiler/ibm.py
@@ -76,7 +76,7 @@ class IBMFCompiler(FCompiler):
                 xlf_cfg = '/etc/opt/ibmcmp/xlf/%s/xlf.cfg' % version
             fo, new_cfg = make_temp_file(suffix='_xlf.cfg')
             log.info('Creating '+new_cfg)
-            with open(xlf_cfg, 'r') as fi:
+            with open(xlf_cfg) as fi:
                 crt1_match = re.compile(r'\s*crt\s*=\s*(?P<path>.*)/crt1.o').match
                 for line in fi:
                     m = crt1_match(line)