Fix verifier ICE on CLOBBER of COMPONENT_REF

[Jan Hubicka <hubicka at ucw dot cz>]

Hi,
the testcase makes inliner to substitute RESULT_DECL by COMPONENT_REF
inside CLOBBER statement. This is not allowed and leads to ICE in
verifier (while I think we should fix code to support this).
This patch simply makes inliner to watch for this case and do not remap
the statement at all.

The testcase works for 32bit only which is bit unfortunate. For 64bit
build NRV does not happen, i did not look into why.

OK?
Honza

	* tree-inline.c (remap_gimple_stmt): Do not subtitute handled components
	to clobber of return value.
	* g++.dg/lto/pr90990_0.C: New testcase.
Index: tree-inline.c
===================================================================
--- tree-inline.c	(revision 272846)
+++ tree-inline.c	(working copy)
@@ -1757,6 +1757,18 @@ remap_gimple_stmt (gimple *stmt, copy_bo
 		return NULL;
 	    }
 	}
+     
+      /* We do not allow CLOBBERs of handled components.  In case
+	 returned value is stored via such handled component, remove
+	 the clobber so stmt verifier is happy.  */
+      if (gimple_clobber_p (stmt)
+	  && TREE_CODE (gimple_assign_lhs (stmt)) == RESULT_DECL)
+	{
+	  tree remapped = remap_decl (gimple_assign_lhs (stmt), id);
+	  if (!DECL_P (remapped)
+	      && TREE_CODE (remapped) != MEM_REF)
+	    return NULL;
+	}
 
       if (gimple_debug_bind_p (stmt))
 	{
Index: testsuite/g++.dg/lto/pr90990_0.C
===================================================================
--- testsuite/g++.dg/lto/pr90990_0.C	(nonexistent)
+++ testsuite/g++.dg/lto/pr90990_0.C	(working copy)
@@ -0,0 +1,31 @@
+// { dg-lto-do link }
+/* { dg-extra-ld-options {  -r -nostdlib } } */
+class A {
+public:
+  float m_floats;
+  A() {}
+};
+class B {
+public:
+  A operator[](int);
+};
+class C {
+  B m_basis;
+
+public:
+  A operator()(A) {
+    m_basis[1] = m_basis[2];
+    A a;
+    return a;
+  }
+};
+class D {
+public:
+  C m_fn1();
+};
+class F {
+  A m_pivotInB;
+  F(D &, const A &);
+};
+F::F(D &p1, const A &p2) : m_pivotInB(p1.m_fn1()(p2)) {}
+