[gcc r14-4040] analyzer: handle volatile ops

[David Malcolm <dmalcolm@gcc.gnu.org>]

https://gcc.gnu.org/g:6319b5b2d4669077e4ddf1e249eeb5602394693c

commit r14-4040-g6319b5b2d4669077e4ddf1e249eeb5602394693c
Author: David Malcolm <dmalcolm@redhat.com>
Date:   Fri Sep 15 13:47:42 2023 -0400

    analyzer: handle volatile ops
    
    gcc/analyzer/ChangeLog:
            * region-model.cc (region_model::get_gassign_result): Handle
            volatile ops by using a conjured_svalue.
    
    gcc/testsuite/ChangeLog:
            * c-c++-common/analyzer/volatile-1.c: New test.
    
    Signed-off-by: David Malcolm <dmalcolm@redhat.com>

Diff:
---
 gcc/analyzer/region-model.cc                     | 11 +++++++++++
 gcc/testsuite/c-c++-common/analyzer/volatile-1.c | 18 ++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-model.cc
index 2e774c2824e..c4e68661ef1 100644
--- a/gcc/analyzer/region-model.cc
+++ b/gcc/analyzer/region-model.cc
@@ -729,6 +729,17 @@ region_model::get_gassign_result (const gassign *assign,
 				   region_model_context *ctxt)
 {
   tree lhs = gimple_assign_lhs (assign);
+
+  if (gimple_has_volatile_ops (assign)
+      && !gimple_clobber_p (assign))
+    {
+      conjured_purge p (this, ctxt);
+      return m_mgr->get_or_create_conjured_svalue (TREE_TYPE (lhs),
+						   assign,
+						   get_lvalue (lhs, ctxt),
+						   p);
+    }
+
   tree rhs1 = gimple_assign_rhs1 (assign);
   enum tree_code op = gimple_assign_rhs_code (assign);
   switch (op)
diff --git a/gcc/testsuite/c-c++-common/analyzer/volatile-1.c b/gcc/testsuite/c-c++-common/analyzer/volatile-1.c
new file mode 100644
index 00000000000..f8440d41220
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/analyzer/volatile-1.c
@@ -0,0 +1,18 @@
+#include "../../gcc.dg/analyzer/analyzer-decls.h"
+
+volatile int g;
+
+void test_global (void)
+{
+  int v1 = g;
+  int v2 = g;
+  __analyzer_eval (v1 == v2); /* { dg-warning "UNKNOWN" } */
+}
+
+void test_local (void)
+{
+  volatile int x = 0;
+  int v1 = x;
+  int v2 = x;
+  __analyzer_eval (v1 == v2); /* { dg-warning "UNKNOWN" } */
+}