sra: Only verify sizes of scalar accesses (PR 93845)

the testcase is another example - in addition to recent PR 93516 - where
the SRA access verifier is confused by the fact that get_ref_base_extent
can return different sizes for the same type, depending whether they are
COMPONENT_REF or not.  In the previous bug I decided to keep the
verifier check for aggregate type even though it is not really important
and instead avoid easily detectable type-within-the-same-type situation.
This testcase is however a result of a fairly random looking type cast
and so cannot be handled in the same way.

Because the check is not really important for aggregates, this patch
simply disables it for non-register types.

2020-02-21  Martin Jambor  <mjambor@suse.cz>

	PR tree-optimization/93845
	* tree-sra.c (verify_sra_access_forest): Only test access size of
	scalar types.

	testsuite/
	* g++.dg/tree-ssa/pr93845.C: New test.

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2020-02-21  Martin Jambor  <mjambor@suse.cz>
+
+	PR tree-optimization/93845
+	* tree-sra.c (verify_sra_access_forest): Only test access size of
+	scalar types.
+
 2020-02-21  Andrew Stubbs  <ams@codesourcery.com>
 
 	* config/gcn/gcn.c (gcn_hard_regno_mode_ok): Align VGPR pairs.

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2020-02-21  Martin Jambor  <mjambor@suse.cz>
+
+	PR tree-optimization/93845
+	* g++.dg/tree-ssa/pr93845.C: New test.
+
 2020-02-21  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* gcc.target/aarch64/sve/rsqrt_1.c: New test.

gcc/testsuite/g++.dg/tree-ssa/pr93845.C

@@ -0,0 +1,30 @@
+/* { dg-do compile } */
+/* { dg-options "-O1" } */
+
+struct g;
+struct h {
+  g *operator->();
+};
+class i {
+  void *a;
+  int b;
+
+public:
+  template <typename f> f j() { return *static_cast<f *>(this); }
+};
+struct k : i {};
+struct l : k {};
+struct m {
+  i n();
+  i o(l, l, int);
+};
+struct g {
+  void m_fn4(k);
+};
+h a;
+i b;
+i m::n() {
+  l c, d, e = o(d, c, 0).j<l>();
+  a->m_fn4(e);
+  return b;
+}

gcc/tree-sra.c

@@ -2355,7 +2355,8 @@ verify_sra_access_forest (struct access *root)
       gcc_assert (offset == access->offset);
       gcc_assert (access->grp_unscalarizable_region
 		  || size == max_size);
-      gcc_assert (max_size == access->size);
+      gcc_assert (!is_gimple_reg_type (access->type)
+		  || max_size == access->size);
       gcc_assert (reverse == access->reverse);
 
       if (access->first_child)