New tests for parallel compilation feature

Adds new tests for testing the parallel compilation engine.
They mainly test issues with regard to symbol promotion clash and
incorrect early assembler output.

2020-08-20  Giuliano Belinassi  <giuliano.belinassi@usp.br>

	* gcc.dg/parallel-early-constant.c: New test.
	* gcc.dg/parallel-static-1.c: New test.
	* gcc.dg/parallel-static-2.c: New test.
	* gcc.dg/parallel-static-clash-1.c: New test.
	* gcc.dg/parallel-static-clash-aux.c: New test.

gcc/testsuite/gcc.dg/parallel-early-constant.c

@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-fparallel-jobs=2 --param=balance-partitions=0" } */
+
+#define A "This is a long test that tests the structure initialization"
+#define B A,A
+#define C B,B,B,B
+#define D C,C,C,C
+
+const char *foo1 ()
+{
+  return A;
+}
+
+int foo2 ()
+{
+  return 42;
+}
+
+int main()
+{
+  char *subs[]={ D, D, D, D, D, D, D, D, D, D, D, D, D, D, D};
+}

gcc/testsuite/gcc.dg/parallel-static-1.c

@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-fparallel-jobs=2 --param=balance-partitions=0" } */
+
+static int global_var;
+
+int foo1(void)
+{
+  global_var = 1;
+}
+
+int foo2(void)
+{
+  global_var = 2;
+}
+
+int main ()
+{
+  foo1 ();
+  foo2 ();
+  return 0;
+}

gcc/testsuite/gcc.dg/parallel-static-2.c

@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-fparallel-jobs=2 --param=balance-partitions=0" } */
+
+int foo1(void)
+{
+  static int var;
+  var = 1;
+}
+
+int foo2(void)
+{
+  static int var;
+  var = 2;
+}
+
+int main ()
+{
+  foo1 ();
+  foo2 ();
+  return 0;
+}

gcc/testsuite/gcc.dg/parallel-static-clash-1.c

@@ -0,0 +1,23 @@
+/* { dg-do run } */
+/* { dg-options "-fparallel-jobs=2 --param=balance-partitions=0 --param=promote-statics=1" } */
+/* { dg-additional-sources "parallel-static-clash-aux.c" } */
+
+int file2_c ();
+
+static int __attribute__ ((noinline))
+private ()
+{
+  return 42;
+}
+
+int
+file1_c ()
+{
+  return private ();
+}
+
+int
+main ()
+{
+  return file1_c () + file2_c ();
+}

gcc/testsuite/gcc.dg/parallel-static-clash-aux.c

@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-fparallel-jobs=2 --param=balance-partitions=0" } */
+
+static int __attribute__ ((noinline))
+private ()
+{
+  return -42;
+}
+
+int
+file2_c ()
+{
+  return private ();
+}