https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96266
Bug ID: 96266
Summary: Macro defined as enum in parens resolves to 1
Product: gcc
Version: 7.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ethouris at gmail dot com
Target Milestone: ---
Created attachment 48906
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48906&action=edit
Preprocessed C++ file with example.
I'm attaching a quite long preprocessed file, but all "simplified examples"
didn't reproduce it. I'm not even sure if this is a bug or a feature (maybe
something related to resolving into `defined()` pp function), but it definitely
works not according to the intention.
This can also be my mistake, but if so, I'm completely unable to find it
despite best efforts.
In short:
1. There's an enum defined, one value is, say, `UPDATE = 0x10`
2. There's a macro defined: `#define ETONLY (UPDATE)`
3. The variable is passed as `int x = 0x11`.
4. The expression `x & ETONLY` resolves to... 1 (not 0x10).
Workaround:
1. Define `ETONLY` as `(0 | UPDATE)`
2. Expression `x & int(ETONLY)` resolves correctly to 0x10.
Tested on gcc 7.5 and some older, including 4.4.
