[PATCH, testsuite] Reliably prune GCC notes in C++ compat suite

["Ulrich Weigand" <uweigand@de.ibm.com>]

Hello,

in testing the rs6000 ABI patches I noted a weird effect: usually, the
-Wpsabi warning notes are ignored in the compat test suites, so we get
a clean test run anyway.

However, when running the C++ version of the struct-layout-1.exp case
*alone* (using RUNTESTFLAGS=struct-layout-1.exp), suddenly tests are
failing because of those extra notes.  This does *not* happen with
the C version of that suite ...

It turns out that that pruning those notes is supposed to happen
from within gcc-defs.exp:${tool}_check_compile:
    if { [info proc ${tool}-dg-prune] != "" } {
        global target_triplet
        set gcc_output [${tool}-dg-prune $target_triplet $gcc_output]
    }

However, the g++-dg-prune routine is defined in g++-dg.exp, which
is never included from g++.dg/compat/struct-layout-1.exp (directly
or indirectly).  Now, when running the full suite, that file would
have been loaded by some earlier g++.dg .exp file, so everything
works out.  But when running struct-layout-1.exp stand-alone, the
g++-dg-prune routine is never defined and thus silently no pruning
takes place.

To fix this, the following patch simply loads g++-dg.exp directly
from g++.dg/compat/struct-layout-1.exp.

Tested on powerpc64-linux and powerpc64le-linux.

OK for mainline (and 4.8/4.9 once the rs6000 ABI patches are
backported there)?

Bye,
Ulrich


gcc/testsuite/ChangeLog:

	* g++.dg/compat/struct-layout-1.exp: Load g++-dg.exp


Index: gcc-4_9-branch/gcc/testsuite/g++.dg/compat/struct-layout-1.exp
===================================================================
--- gcc-4_9-branch.orig/gcc/testsuite/g++.dg/compat/struct-layout-1.exp
+++ gcc-4_9-branch/gcc/testsuite/g++.dg/compat/struct-layout-1.exp
@@ -89,6 +89,9 @@ proc compat-use-tst-compiler { } {
 # This must be done after the compat-use-*-compiler definitions.
 load_lib compat.exp
 
+# Provide the g++-dg-prune routine (gcc-dp.exp is loaded by compat.exp)
+load_lib g++-dg.exp
+
 g++_init
 
 # Save variables for the C++ compiler under test, which each test will

-- 
  Dr. Ulrich Weigand
  GNU/Linux compilers and toolchain
  Ulrich.Weigand@de.ibm.com