re PR target/49551 (tentative declaration after definition and -fdata-sections…

re PR target/49551 (tentative declaration after definition and -fdata-sections cause ICE in C front-end.)

2015-06-02  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>

        PR c/49551
        * c-decl.c (merge_decls): Merge DECL_COMMON.
        * gcc.dg/pr49551.c: New test-case.

From-SVN: r224033

gcc/c/ChangeLog

+2015-06-02  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
+
+	PR c/49551
+	* c-decl.c (merge_decls): Merge DECL_COMMON.
+
 2015-05-22  Jim Wilson  <jim.wilson@linaro.org>
 
 	* Make-lang.in (check_gcc_pallelize): Define.

gcc/c/c-decl.c

@@ -2631,6 +2631,12 @@ merge_decls (tree newdecl, tree olddecl, tree newtype, tree oldtype)
   else if (DECL_PRESERVE_P (newdecl))
     DECL_PRESERVE_P (olddecl) = 1;
 
+  /* Merge DECL_COMMON */
+  if (VAR_P (olddecl) && VAR_P (newdecl)
+      && !lookup_attribute ("common", DECL_ATTRIBUTES (newdecl))
+      && !lookup_attribute ("nocommon", DECL_ATTRIBUTES (newdecl)))
+    DECL_COMMON (newdecl) = DECL_COMMON (newdecl) && DECL_COMMON (olddecl);
+
   /* Copy most of the decl-specific fields of NEWDECL into OLDDECL.
      But preserve OLDDECL's DECL_UID, DECL_CONTEXT and
      DECL_ARGUMENTS (if appropriate).  */

gcc/testsuite/ChangeLog

+2015-06-02  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
+
+	PR c/49551
+	* gcc.dg/pr49551.c: New testcase.
+
 2015-06-02  Richard Biener  <rguenther@suse.de>
 
 	PR debug/65549

gcc/testsuite/gcc.dg/pr49551.c

+/* { dg-do compile } */
+/* { dg-options "-O -fdata-sections" } */
+
+int x = 1;
+int x;
+
+/* { dg-final { scan-assembler-not {comm[\t ]+x} } } */