[Bug c/54391] New: transparent_union typedef'ing inconsistent
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54391
Bug #: 54391
Summary: transparent_union typedef'ing inconsistent
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: de...@fresse.org
This works as expected:
union __attribute__((transparent_union)) m30_u {
uint32_t u;
};
typedef union m30_u m30_t;
static inline double
make_double(m30_t m)
{
return (double)m.u;
}
But typedef'ing upfront does not:
typedef union m30_u m30_t;
union __attribute__((transparent_union)) m30_u {
uint32_t u;
};
static inline double
make_double(m30_t m)
{
return (double)m.u;
}
...
uint32_t bar = 17;
make_double(bar);
transpu.c:27:2: error: incompatible type for argument 1 of 'make_double'
printf("%.6f\n", make_double());
transpu.c:11:1: note: expected 'm30_t' but argument is of type 'uint32_t'
This is very inconsistent.
[Bug c/54823] New: string literal characters not constant
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54823
Bug #: 54823
Summary: string literal characters not constant
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: de...@fresse.org
this:
int main(void)
{
int c = *" ";
printf("%x\n", c);
return 0;
}
results in (the constant expression):
movl$32, %eax
But this:
int main(void)
{
enum {foo = *" "};
printf("%x\n", foo);
return 0;
}
gives
error: enumerator value for 'foo' is not an integer constant.
Whereas icc for instance just accepts the second form as constant integer
expression.
[Bug c/54823] string literal characters not constant
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54823
--- Comment #3 from Sebastian Freundt 2012-10-05
11:46:20 UTC ---
I'm more or less referring to the internals, why is it a constant expression in
the first case, but not treated as an integer constant expression.
Also, according to the rules of indirection (6.5.3.2):
If [a string literal X] has type "pointer to TYPE" then *X should have type X.
Now if internally *" " is a integer (or char) internally, and taking the rules
of indirection literally, then
enum {foo = *" "};
should be (in my eyes) the same as
enum {foo = (char)32};
[Bug c/54823] string literal characters not constant
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54823 --- Comment #5 from Sebastian Freundt 2012-10-05 12:45:45 UTC --- Ok, I see. I assume, there's no plans on widening the allowed expressions for constant integers? It's autogenerated code a la: #define foo "bar" (foo)[1] * 0x55 + (foo)[2] * 0x30 where the indices are calculated. I was trying to port the generated code to gcc. Thanks anyway.
[Bug c/50422] New: -Wswitch warns about unhandled cases in nested switches
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50422 Bug #: 50422 Summary: -Wswitch warns about unhandled cases in nested switches Classification: Unclassified Product: gcc Version: 4.7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassig...@gcc.gnu.org ReportedBy: de...@fresse.org Linux plutos 2.6.37.6-0.7-desktop #1 SMP PREEMPT 2011-07-21 02:17:24 +0200 x86_64 x86_64 x86_64 GNU/Linux freundt@clyde:pts/10:~> gcc --version gcc (GCC) 4.7.0 20110811 (experimental) Copyright (C) 2011 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Recipe to reproduce: freundt@clyde:pts/10:~> gcc -x c -c -Wall -o /dev/null - <: In function 'test': :13:3: warning: enumeration value 'TWO' not handled in switch [-Wswitch] This is _similar_ to bug 23577 but not quite as nested switches should be easier to handle than separate fragments.
