PR target/83100

	* varasm.c (bss_initializer_p): Return true for DECL_COMMON
	TREE_READONLY decls.

	* gcc.dg/pr83100-1.c: New test.
	* gcc.dg/pr83100-2.c: New test.
	* gcc.dg/pr83100-3.c: New test.
	* gcc.dg/pr83100-4.c: New test.


git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@255160 138bc75d-0d04-0410-961f-82ee72b054a4

7 files changed, 52 insertions, 3 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index dc980a96a0d..7189a66ed83 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-11-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/83100
+	* varasm.c (bss_initializer_p): Return true for DECL_COMMON
+	TREE_READONLY decls.
+
 2017-11-27  Markus Trippelsdorf  <markus@trippelsdorf.de>
 
 	PR rtl-optimization/82488
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f750ad7b333..ff40f3657e3 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2017-11-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/83100
+	* gcc.dg/pr83100-1.c: New test.
+	* gcc.dg/pr83100-2.c: New test.
+	* gcc.dg/pr83100-3.c: New test.
+	* gcc.dg/pr83100-4.c: New test.
+
 2017-11-26  Julia Koval  <julia.koval@intel.com>
 
 	* gcc.target/i386/funcspec-56.inc: Handle new march.
diff --git a/gcc/testsuite/gcc.dg/pr83100-1.c b/gcc/testsuite/gcc.dg/pr83100-1.c
new file mode 100644
index 00000000000..233c1f687b0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr83100-1.c
@@ -0,0 +1,7 @@
+/* PR target/83100 */
+/* { dg-do compile { target *-*-linux* *-*-gnu* } } */
+/* { dg-options "-O2 -fcommon -fdata-sections" } */
+
+const int a;
+
+/* { dg-final { scan-assembler "comm" } } */
diff --git a/gcc/testsuite/gcc.dg/pr83100-2.c b/gcc/testsuite/gcc.dg/pr83100-2.c
new file mode 100644
index 00000000000..6dbe93dcd16
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr83100-2.c
@@ -0,0 +1,15 @@
+/* PR target/83100 */
+/* { dg-do run } */
+/* { dg-options "-O2 -fcommon -fdata-sections" } */
+/* { dg-additional-sources pr83100-3.c } */
+/* { dg-skip-if "-fdata-sections not supported" { hppa*-*-hpux* nvptx-*-* } } */
+
+const int a;
+
+int
+main ()
+{
+  if (a != 7)
+    __builtin_abort ();
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/pr83100-3.c b/gcc/testsuite/gcc.dg/pr83100-3.c
new file mode 100644
index 00000000000..a28e852695f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr83100-3.c
@@ -0,0 +1,6 @@
+/* PR target/83100 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fcommon -fdata-sections" } */
+/* { dg-skip-if "-fdata-sections not supported" { hppa*-*-hpux* nvptx-*-* } } */
+
+const int a = 7;
diff --git a/gcc/testsuite/gcc.dg/pr83100-4.c b/gcc/testsuite/gcc.dg/pr83100-4.c
new file mode 100644
index 00000000000..bb26735dd1b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr83100-4.c
@@ -0,0 +1,7 @@
+/* PR target/83100 */
+/* { dg-do compile { target *-*-linux* *-*-gnu* } } */
+/* { dg-options "-O2 -fno-common -fdata-sections" } */
+
+const int a;
+
+/* { dg-final { scan-assembler "rodata.a" { target i?86-*-* x86_64-*-* } } } */
diff --git a/gcc/varasm.c b/gcc/varasm.c
index 923399d71a4..ff912b7fa57 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -986,9 +986,9 @@ decode_reg_name (const char *name)
 bool
 bss_initializer_p (const_tree decl)
 {
-  /* Do not put constants into the .bss section, they belong in a readonly
-     section.  */
-  return (!TREE_READONLY (decl)
+  /* Do not put non-common constants into the .bss section, they belong in
+     a readonly section.  */
+  return ((!TREE_READONLY (decl) || DECL_COMMON (decl))
 	  && (DECL_INITIAL (decl) == NULL
 	      /* In LTO we have no errors in program; error_mark_node is used
 	         to mark offlined constructors.  */