diff mbox series

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

Message ID 20190111223538.22509-1-jason@redhat.com
State New
Headers show
Series [C++] PR c++/88613 - ICE with use of const var in lambda. | expand

Commit Message

Jason Merrill Jan. 11, 2019, 10:35 p.m. UTC 
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.

Tested x86_64-cp-linux-gnu, applying to trunk.

	* expr.c (mark_use): Fix location wrapper handling.
	* cp-gimplify.c (cp_fold_maybe_rvalue): Call mark_rvalue_use.
---
 gcc/cp/cp-gimplify.c                            |  2 ++
 gcc/cp/expr.c                                   | 17 +++++++++++++++--
 .../g++.dg/cpp0x/lambda/lambda-const10.C        | 11 +++++++++++
 gcc/cp/ChangeLog                                |  6 ++++++
 4 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-const10.C


base-commit: ead1f4b6412011a79e84db928f6a98dd7cf09a3d
diff mbox series

Patch

diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c
index 726adac4f4e..121dfa41d8d 100644
--- 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 071c6fb9205..9160043ed11 100644
--- 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
index 00000000000..3112f08f5c2
--- /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)
+      ;
+  }();
+}
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 4b9fa821d74..74e4dff494e 100644
--- 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  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* decl.c (start_decl): Improve error location.