In StructAssign: be careful not to duplicate accesses to a volatile variable.

git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1551 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e

3 files changed, 24 insertions, 9 deletions

diff --git a/cparser/StructAssign.ml b/cparser/StructAssign.ml
index 51cb4896..925170bf 100644
--- a/cparser/StructAssign.ml
+++ b/cparser/StructAssign.ml
@@ -133,21 +133,23 @@ let transf_assign env lhs rhs =
 
 (* Detect invariant l-values *)
 
-let rec invariant_lvalue e =
+let not_volatile env ty = not (List.mem AVolatile (attributes_of_type env ty))
+
+let rec invariant_lvalue env e =
   match e.edesc with
   | EVar _ -> true
-  | EUnop(Oderef, {edesc = EVar _}) -> true   (* to check *)
-  | EUnop(Odot _, e1) -> invariant_lvalue e1
+  | EUnop(Oderef, {edesc = EVar _; etyp = ty}) -> not_volatile env ty
+  | EUnop(Odot _, e1) -> invariant_lvalue env e1
   | _ -> false
 
 (* Bind a l-value to a temporary variable if it is not invariant. *)
 
-let rec bind_lvalue e fn =
+let rec bind_lvalue env e fn =
   match e.edesc with
   | EBinop(Ocomma, e1, e2, _) ->
-      ecomma e1 (bind_lvalue e2 fn)
+      ecomma e1 (bind_lvalue env e2 fn)
   | _ ->
-      if invariant_lvalue e then
+      if invariant_lvalue env e then
         fn e
       else begin
         let tmp = new_temp (TPtr(e.etyp, [])) in
@@ -162,8 +164,8 @@ type context = Val | Effects
 let rec transf_expr env ctx e =
   match e.edesc with
   | EBinop(Oassign, lhs, rhs, _) when is_composite_type env lhs.etyp ->
-      bind_lvalue (transf_expr env Val lhs) (fun l ->
-      bind_lvalue (transf_expr env Val rhs) (fun r ->
+      bind_lvalue env (transf_expr env Val lhs) (fun l ->
+      bind_lvalue env (transf_expr env Val rhs) (fun r ->
         let e' = transf_assign env l r in
         if ctx = Val then ecomma e' l else e'))
   | EConst c -> e
diff --git a/test/regression/Makefile b/test/regression/Makefile
index c1925c79..a385cc48 100644
--- a/test/regression/Makefile
+++ b/test/regression/Makefile
@@ -16,7 +16,7 @@ TESTS=bitfields1 bitfields2 bitfields3 bitfields4 \
 # Other tests: should compile to .s without errors (but expect warnings)
 EXTRAS=annot1 commaprec expr2 expr3 expr4 extern1 funct2 funptr1 init1 \
   init2 init3 init4 pragmas ptrs1 ptrs2 sizeof1 struct1 struct2 struct3 \
-  struct4 struct5 struct6 types1 volatile1
+  struct4 struct5 struct6 struct9 types1 volatile1
 
 # Test known to fail
 FAILURES=funct1 varargs1
diff --git a/test/regression/struct9.c b/test/regression/struct9.c
new file mode 100644
index 00000000..fae137ce
--- /dev/null
+++ b/test/regression/struct9.c
@@ -0,0 +1,13 @@
+struct S1 {
+  unsigned char  f0;
+  short  f1;
+};
+
+struct S1 g_77 = {0x73,9};
+struct S1 * volatile g_85 = &g_77;
+struct S1 g_204 = {0xAD,0x9086};
+
+void func_1(void)
+{
+   *g_85 = g_204;
+}