PR c++/88613 - ICE with use of const var in lambda.

The issue here was that we were cp_folding a location wrapper around a
lambda capture proxy before it had been mark_rvalue_used.  I considered
adding mark_rvalue_use calls to build_new_op_1, but it seems appropriate to
have them in cp_fold_maybe_rvalue when we know we're trying to produce an
rvalue.

The change to mark_use is for a related issue: when we change the operand of
the location wrapper from VAR_DECL to INTEGER_CST, we need the TREE_CODE of
the location wrapper to change as well, from VIEW_CONVERT_EXPR to
NON_LVALUE_EXPR.

	* expr.c (mark_use): Fix location wrapper handling.
	* cp-gimplify.c (cp_fold_maybe_rvalue): Call mark_rvalue_use.

From-SVN: r267859

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 5a5256f..9208f1e 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2019-01-11  Jason Merrill  <jason@redhat.com>
+
+       PR c++/88613 - ICE with use of const var in lambda.
+       * expr.c (mark_use): Fix location wrapper handling.
+       * cp-gimplify.c (cp_fold_maybe_rvalue): Call mark_rvalue_use.
+
 2019-01-11  Tobias Burnus  <burnus@net-b.de>
 
        PR C++/88114

diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c
index 726adac..121dfa4 100644 (file)
--- a/gcc/cp/cp-gimplify.c
+++ b/gcc/cp/cp-gimplify.c
@@ -2124,6 +2124,8 @@ cp_fold_maybe_rvalue (tree x, bool rval)
   while (true)
     {
       x = cp_fold (x);
+      if (rval)
+       x = mark_rvalue_use (x);
       if (rval && DECL_P (x)
          && !TYPE_REF_P (TREE_TYPE (x)))
        {

diff --git a/gcc/cp/expr.c b/gcc/cp/expr.c
index 071c6fb..9160043 100644 (file)
--- a/gcc/cp/expr.c
+++ b/gcc/cp/expr.c
@@ -187,10 +187,23 @@ mark_use (tree expr, bool rvalue_p, bool read_p,
        }
       break;
 
-    CASE_CONVERT:
     case VIEW_CONVERT_EXPR:
       if (location_wrapper_p (expr))
-       loc = EXPR_LOCATION (expr);
+       {
+         loc = EXPR_LOCATION (expr);
+         tree op = TREE_OPERAND (expr, 0);
+         tree nop = RECUR (op);
+         if (nop == error_mark_node)
+           return error_mark_node;
+         TREE_OPERAND (expr, 0) = nop;
+         /* If we're replacing a DECL with a constant, we also need to change
+            the TREE_CODE of the location wrapper.  */
+         if (op != nop && rvalue_p)
+           TREE_SET_CODE (expr, NON_LVALUE_EXPR);
+         return expr;
+       }
+      gcc_fallthrough();
+    CASE_CONVERT:
       recurse_op[0] = true;
       break;
 

diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-const10.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-const10.C
new file mode 100644 (file)
index 0000000..3112f08
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-const10.C
@@ -0,0 +1,11 @@
+// PR c++/88613
+// { dg-do compile { target c++11 } }
+// { dg-additional-options -Wtautological-compare }
+
+void a() {
+  const int b = 5;
+  [=] {
+    if (b != 5)
+      ;
+  }();
+}