fortran: Fix invalid function decl clobber ICE [PR105012]

The fortran frontend, as result symbol for a function without
declared result symbol, uses the function symbol itself.  This caused
an invalid clobber of a function decl to be emitted, leading to an
ICE, whereas the intended behaviour was to clobber the function result
variable.  This change fixes the problem by getting the decl from the
just-retrieved variable reference after the call to
gfc_conv_expr_reference, instead of copying it from the frontend symbol.

	PR fortran/105012

gcc/fortran/ChangeLog:

	* trans-expr.cc (gfc_conv_procedure_call): Retrieve variable
	from the just calculated variable reference.

gcc/testsuite/ChangeLog:

	* gfortran.dg/intent_out_15.f90: New test.

(cherry picked from commit edaf1e005c90b311c39b46d85cea17befbece112)

diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
index 3cfde439cc0f092b75e79346d2c24de2e1b5c700..fe979ce852d10e486e0e8c002b1ff7682954f9c6 100644 (file)
--- a/gcc/fortran/trans-expr.cc
+++ b/gcc/fortran/trans-expr.cc
@@ -6534,7 +6534,8 @@ gfc_conv_procedure_call (gfc_se * se, gfc_symbol * sym,
                          tree var;
                          /* FIXME: This fails if var is passed by reference, see PR
                             41453.  */
-                         var = e->symtree->n.sym->backend_decl;
+                         var = build_fold_indirect_ref_loc (input_location,
+                                                            parmse.expr);
                          tree clobber = build_clobber (TREE_TYPE (var));
                          gfc_add_modify (&se->pre, var, clobber);
                        }

diff --git a/gcc/testsuite/gfortran.dg/intent_out_15.f90 b/gcc/testsuite/gfortran.dg/intent_out_15.f90
new file mode 100644 (file)
index 0000000..64334e6
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/intent_out_15.f90
@@ -0,0 +1,27 @@
+! { dg-do compile }
+! { dg-additional-options "-fdump-tree-original" }
+!
+! PR fortran/105012
+! The following case was triggering an ICE because of a clobber
+! on the DERFC function decl instead of its result.
+
+module error_function
+integer, parameter :: r8 = selected_real_kind(12) ! 8 byte real
+contains
+SUBROUTINE CALERF_r8(ARG, RESULT, JINT)
+   integer, parameter :: rk = r8
+   real(rk), intent(in)  :: arg
+   real(rk), intent(out) :: result
+   IF (Y .LE. THRESH) THEN
+   END IF
+end SUBROUTINE CALERF_r8
+FUNCTION DERFC(X)
+   integer, parameter :: rk = r8 ! 8 byte real
+   real(rk), intent(in) :: X
+   real(rk) :: DERFC
+   CALL CALERF_r8(X, DERFC, JINT)
+END FUNCTION DERFC
+end module error_function
+
+! { dg-final { scan-tree-dump-times "CLOBBER" 1 "original" } }
+! { dg-final { scan-tree-dump "__result_derfc = {CLOBBER};" "original" } }