From 517fb1a78102df43f052c6934c27dd51d786aff7 Mon Sep 17 00:00:00 2001
From: Steve Kargl <kargl@gcc.gnu.org>
Date: Fri, 15 Jul 2022 22:07:15 +0200
Subject: [PATCH] Fortran: do not generate conflicting results under -ff2c
 [PR104313]

gcc/fortran/ChangeLog:

	PR fortran/104313
	* trans-decl.cc (gfc_generate_return): Do not generate conflicting
	fake results for functions with no result variable under -ff2c.

gcc/testsuite/ChangeLog:

	PR fortran/104313
	* gfortran.dg/pr104313.f: New test.
---
 gcc/fortran/trans-decl.cc            |  2 +-
 gcc/testsuite/gfortran.dg/pr104313.f | 11 +++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gfortran.dg/pr104313.f

diff --git a/gcc/fortran/trans-decl.cc b/gcc/fortran/trans-decl.cc
index 6493cc2f6b1..908a4c6d42e 100644
--- a/gcc/fortran/trans-decl.cc
+++ b/gcc/fortran/trans-decl.cc
@@ -6474,7 +6474,7 @@ gfc_generate_return (void)
 	     NULL_TREE, and a 'return' is generated without a variable.
 	     The following generates a 'return __result_XXX' where XXX is
 	     the function name.  */
-	  if (sym == sym->result && sym->attr.function)
+	  if (sym == sym->result && sym->attr.function && !flag_f2c)
 	    {
 	      result = gfc_get_fake_result_decl (sym, 0);
 	      result = fold_build2_loc (input_location, MODIFY_EXPR,
diff --git a/gcc/testsuite/gfortran.dg/pr104313.f b/gcc/testsuite/gfortran.dg/pr104313.f
new file mode 100644
index 00000000000..89c8947cb0a
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr104313.f
@@ -0,0 +1,11 @@
+! { dg-do compile }
+! { dg-additional-options "-ff2c -fdump-tree-original" }
+!
+! PR fortran/104313 - ICE verify_gimple failed with -ff2c
+! Contributed by G.Steinmetz
+
+      function f(a)
+      return
+      end
+
+! { dg-final { scan-tree-dump-times "return" 1 "original" } }
--
2.35.3