analyzer: fix ICE with equiv_class constant (PR 93649)

gcc/analyzer/ChangeLog:
	PR analyzer/93649
	* constraint-manager.cc (constraint_manager::add_constraint): When
	merging equivalence classes and updating m_constant, also update
	m_cst_sid.
	(constraint_manager::validate): If m_constant is non-NULL assert
	that m_cst_sid is non-null and is valid.

gcc/testsuite/ChangeLog:
	PR analyzer/93649
	* gcc.dg/analyzer/torture/pr93649.c: New test.

4 files changed, 86 insertions, 2 deletions

diff --git a/gcc/analyzer/ChangeLog b/gcc/analyzer/ChangeLog
index df04b02..38afa69 100644
--- a/gcc/analyzer/ChangeLog
+++ b/gcc/analyzer/ChangeLog
@@ -1,5 +1,14 @@
 2020-02-11  David Malcolm  <dmalcolm@redhat.com>
 
+	PR analyzer/93649
+	* constraint-manager.cc (constraint_manager::add_constraint): When
+	merging equivalence classes and updating m_constant, also update
+	m_cst_sid.
+	(constraint_manager::validate): If m_constant is non-NULL assert
+	that m_cst_sid is non-null and is valid.
+
+2020-02-11  David Malcolm  <dmalcolm@redhat.com>
+
 	PR analyzer/93657
 	* analyzer.opt (fdump-analyzer): Reword description.
 	(fdump-analyzer-stderr): Likewise.
diff --git a/gcc/analyzer/constraint-manager.cc b/gcc/analyzer/constraint-manager.cc
index d5a6939..a623543 100644
--- a/gcc/analyzer/constraint-manager.cc
+++ b/gcc/analyzer/constraint-manager.cc
@@ -686,8 +686,8 @@ constraint_manager::add_constraint (equiv_class_id lhs_ec_id,
 
 	if (rhs_ec_obj.m_constant)
 	  {
-	    //gcc_assert (lhs_ec_obj.m_constant == NULL);
 	    lhs_ec_obj.m_constant = rhs_ec_obj.m_constant;
+	    lhs_ec_obj.m_cst_sid = rhs_ec_obj.m_cst_sid;
 	  }
 
 	/* Drop rhs equivalence class, overwriting it with the
@@ -1516,7 +1516,11 @@ constraint_manager::validate () const
 	  gcc_assert (sid->as_int () < get_num_svalues ());
 	}
       if (ec->m_constant)
-	gcc_assert (CONSTANT_CLASS_P (ec->m_constant));
+	{
+	  gcc_assert (CONSTANT_CLASS_P (ec->m_constant));
+	  gcc_assert (!ec->m_cst_sid.null_p ());
+	  gcc_assert (ec->m_cst_sid.as_int () < get_num_svalues ());
+	}
 #if 0
       else
 	gcc_assert (ec->m_vars.length () > 0);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 27aa4ac..2ca519c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-02-11  David Malcolm  <dmalcolm@redhat.com>
+
+	PR analyzer/93649
+	* gcc.dg/analyzer/torture/pr93649.c: New test.
+
 2020-02-11  Will Schmidt  <will_schmidt@vnet.ibm.com>
 
 	* gcc.target/powerpc/pr70010-2.c: Add -maltivec.
diff --git a/gcc/testsuite/gcc.dg/analyzer/torture/pr93649.c b/gcc/testsuite/gcc.dg/analyzer/torture/pr93649.c
new file mode 100644
index 0000000..9d92939
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/analyzer/torture/pr93649.c
@@ -0,0 +1,66 @@
+/* { dg-additional-options "-Wno-incompatible-pointer-types -Wno-analyzer-too-complex" } */
+/* TODO: ideally we shouldn't have -Wno-analyzer-too-complex above; it
+   appears to be needed due to the recursion.  */
+
+struct tz {
+  int qc;
+};
+
+struct wp {
+  struct tz *p2;
+} *ov;
+
+struct dz {
+  struct wp *r5;
+};
+
+void
+za (void);
+
+void
+h5 (struct dz *);
+
+int
+e7 (struct wp *f2)
+{
+  return f2 == ov;
+}
+
+void
+wr (struct wp *sw)
+{
+  if (sw != 0)
+    za ();
+}
+
+void
+m6 (const struct dz *gq)
+{
+  wr (gq->r5);
+
+  asm ("" : "+m" (gq));
+
+  if (0)
+    {
+      asm ("" : "+m" (gq->r5->p2->qc));
+      asm ("" : "+m" (gq->r5->p2->qc));
+    }
+
+  asm ("" : "+m" (gq->r5->p2->qc));
+
+  if (e7 (gq->r5))
+    za ();
+}
+
+void
+ts (struct dz *cx)
+{
+  struct dz nt;
+
+  if (nt.r5)
+    {
+      m6 (cx);
+      h5 (cx);
+      ts (&cx);
+    }
+}