On Mon, Feb 1, 2016 at 10:28 AM, Nicolai Stange <nicstange@xxxxxxxxx> wrote:
> Here comes the greatly enhanced v3 of this series.
>
> Luc's suggestions about splitting some patches turned out to be very fruitful!
OK, I am taking a stab at his again. Sorry for the long hold off.
I will reply from this thread instead of finding the right patch email
to reply on.
+++ validation/constexpr-cast.c 2016-11-23 09:57:37.638646787 +0800
@@ -0,0 +1,25 @@
+static int a[] = {
+ [(int)0] = 0, // OK
+ [(int)(int)0] = 0, // OK
+ [(int)0.] = 0, // OK
+ [(int)(int)0.] = 0, // OK
+ [(int)__builtin_choose_expr(0, 0, 0)] = 0, // OK
+ [(int)__builtin_choose_expr(0, 0, 0.)] = 0, // OK
+
+ [(int)(float)0] = 0, // KO
Why is this one KO? It seems perfectly fine to force a floating
type into a integer constant expression.
per [6.6.6] quote: on integer constant expression:
" and floating constants that are the
immediate operands of casts. Cast operators in an integer constant
expression shall only
convert arithmetic types to integer types,"
+ [(int)(float)0.] = 0, // KO
+
+ [(int)(void*)0] = 0, // KO
Also this one should be fine?
[6.7.8.6] quote as
" If a designator has the form
[ constant-expression ]
then the current object (defined below) shall have array type and the
expression shall be
an *integer constant expression*."
So it seems the only requirement is *integer constant expression*.
why (int)(void*)0 is not integer constant expression? Sure there is
a warning about converting the (void*) into (int) for a different size.
But that is a separate issue.
Chris
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