diff --git a/lib/spack/spack/compilers/xl.py b/lib/spack/spack/compilers/xl.py
index 77a5ed7acd..686807ae33 100644
--- a/lib/spack/spack/compilers/xl.py
+++ b/lib/spack/spack/compilers/xl.py
@@ -67,13 +67,7 @@ def fflags(self):
         # compilers and allows the use of zero size objects.
         # For Fortran 90 and beyond, it is set by default and has not impact.
         # Its use has no negative side effects.
-        # The -qstrict flag allows the Fortran 90+ compilers to parse the
-        # source files using fixed form rule. As a result, if -qfixed is in
-        # effect, free form files (that are not also fixed form files) will
-        # fail to compile regardless of the compiler invocation command.
-        # Use the -qfree flag in the packages' configuration file to undo the
-        #  -qfixed flag, as the last one wins.
-        return "-qzerosize -qfixed"
+        return "-qzerosize"
 
     @classmethod
     def default_version(cls, comp):
diff --git a/lib/spack/spack/compilers/xl_r.py b/lib/spack/spack/compilers/xl_r.py
index ca76f219ce..d08e700f42 100644
--- a/lib/spack/spack/compilers/xl_r.py
+++ b/lib/spack/spack/compilers/xl_r.py
@@ -68,13 +68,7 @@ def fflags(self):
         # compilers and allows the use of zero size objects.
         # For Fortran 90 and beyond, it is set by default and has not impact.
         # Its use has no negative side effects.
-        # The -qstrict flag allows the Fortran 90+ compilers to parse the
-        # source files using fixed form rule. As a result, if -qfixed is in
-        # effect, free form files (that are not also fixed form files) will
-        # fail to compile regardless of the compiler invocation command.
-        # Use the -qfree flag in the packages' configuration file to undo the
-        #  -qfixed flag, as the last one wins.
-        return "-qzerosize -qfixed"
+        return "-qzerosize"
 
     @classmethod
     def default_version(self, comp):