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Re: [C++ Patch] PR 54170

From: Jason Merrill <jason at redhat dot com>
To: Paolo Carlini <paolo dot carlini at oracle dot com>
Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
Date: Sat, 01 Dec 2012 01:13:32 -0500
Subject: Re: [C++ Patch] PR 54170
References: <50B91F80.3080100@oracle.com>

On 11/30/2012 04:05 PM, Paolo Carlini wrote:

@@ -219,10 +219,15 @@ cp_convert_to_pointer (tree type, tree expr, tsubs
-	expr = build_int_cst (type, 0);
+	expr = (TREE_SIDE_EFFECTS (expr)
+		? build_nop (type, expr)
+		: build_int_cst (type, 0));

This seems to rely on a nop being sufficient to convert from any null pointer constant to the appropriate pointer type, which I don't think is safe if the integer is smaller than a pointer.

I'm also not sure if we want to rely on nullptr_t expressions actually having the value 0.

-      pfn = build_c_cast (input_location, type, nullptr_node);
+      pfn = (TREE_SIDE_EFFECTS (pfn)
+	     ? build_nop (type, pfn)
+	     : build_c_cast (input_location, type, nullptr_node));

Here we should be able to just convert pfn to the appropriate function pointer type so that we don't need to duplicate the logic.

Jason

Follow-Ups:
- Re: [C++ Patch] PR 54170
  - From: Paolo Carlini

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