| From: |
| "Uecker, Martin" <Martin.Uecker-AT-med.uni-goettingen.de> |
| To: |
| "torvalds-AT-linux-foundation.org" <torvalds-AT-linux-foundation.org> |
| Subject: |
| detecting integer constant expressions in macros |
| Date: |
| Tue, 20 Mar 2018 22:13:35 +0000 |
| Message-ID: |
| <1521584015.31174.3.camel@med.uni-goettingen.de> |
| Cc: |
| "linux-kernel-AT-vger.kernel.org" <linux-kernel-AT-vger.kernel.org> |
Hi Linus,
here is an idea:
a test for integer constant expressions which returns an
integer constant expression itself which should be suitable
for passing to __builtin_choose_expr might be:
#define ICE_P(x) (sizeof(int) == sizeof(*(1 ? ((void*)((x) * 0l)) :
(int*)1)))
This also does not evaluate x itself on gcc although this is
not guaranteed by the standard. (And I haven't tried any older
gcc.)
Best,
Martin
