I have committed the attached patch as obvious (Rev. 182497).
gfortran merged the symbol of a local label like:
label_name: block
end block label_name
with a later-declared procedure with the same name ("subroutine
label_name()") which lead to an ICE and interesting code paths.
Built, regtested and committed on x86-64-linux.
Tobias
Index: gcc/fortran/ChangeLog
===================================================================
--- gcc/fortran/ChangeLog (Revision 182496)
+++ gcc/fortran/ChangeLog (Arbeitskopie)
@@ -1,6 +1,12 @@
2011-12-19 Tobias Burnus <bur...@net-b.de>
PR fortran/51605
+ * parse.c (gfc_fixup_sibling_symbols): Regard FL_LABEL as
+ local symbol.
+
+2011-12-19 Tobias Burnus <bur...@net-b.de>
+
+ PR fortran/51605
* match.c (gfc_match_select_type): Handle
scalar polymophic coarrays.
(select_type_set_tmp, ): Ditto; avoid segfault if !class_ok.
Index: gcc/fortran/parse.c
===================================================================
--- gcc/fortran/parse.c (Revision 182496)
+++ gcc/fortran/parse.c (Arbeitskopie)
@@ -3908,6 +3908,7 @@
|| old_sym->attr.intrinsic
|| old_sym->attr.generic
|| old_sym->attr.flavor == FL_NAMELIST
+ || old_sym->attr.flavor == FL_LABEL
|| old_sym->attr.proc == PROC_ST_FUNCTION))
{
/* Replace it with the symbol from the parent namespace. */
Index: gcc/testsuite/gfortran.dg/block_10.f90
===================================================================
--- gcc/testsuite/gfortran.dg/block_10.f90 (Revision 0)
+++ gcc/testsuite/gfortran.dg/block_10.f90 (Arbeitskopie)
@@ -0,0 +1,34 @@
+! { dg-do compile }
+!
+! PR fortran/51605
+!
+
+contains
+ subroutine foo
+ BLOCK_NAME: block
+ end block BLOCK_NAME
+ end subroutine foo
+
+ subroutine BLOCK_NAME()
+ end subroutine BLOCK_NAME
+
+ subroutine bar()
+ end subroutine bar
+end
+
+subroutine test()
+contains
+ subroutine BLOCK_NAME()
+ end subroutine BLOCK_NAME
+
+ subroutine foobar()
+ end subroutine foobar
+
+ subroutine foo
+ BLOCK_NAME: block
+ end block BLOCK_NAME
+ end subroutine foo
+
+ subroutine bar()
+ end subroutine bar
+end
Index: gcc/testsuite/ChangeLog
===================================================================
--- gcc/testsuite/ChangeLog (Revision 182496)
+++ gcc/testsuite/ChangeLog (Arbeitskopie)
@@ -1,3 +1,8 @@
+2011-12-19 Tobias Burnus <bur...@net-b.de>
+
+ PR fortran/51605
+ * gfortran.dg/block_10.f90: New.
+
2011-12-19 Jason Merrill <ja...@redhat.com>
PR c++/51553
