On 18/06/20 08:55 +0100, Richard Sandiford wrote:
Sebastian Huber <sebastian.hu...@embedded-brains.de> writes:
On 18/06/2020 09:09, Richard Sandiford wrote:
Sebastian Huber <sebastian.hu...@embedded-brains.de> writes:
On 16/06/2020 12:42, Richard Sandiford wrote:
[...]
2020-06-16 Richard Sandiford <richard.sandif...@arm.com>
gcc/
* coretypes.h (first_type): New alias template.
* recog.h (insn_gen_fn::operator()): Use it instead of a decltype.
Remove spurious “...” and split the function type out into a typedef.
---
gcc/coretypes.h | 4 ++++
gcc/recog.h | 5 +++--
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/gcc/coretypes.h b/gcc/coretypes.h
index cda22697cc3..01ec2e23ce2 100644
--- a/gcc/coretypes.h
+++ b/gcc/coretypes.h
@@ -359,6 +359,10 @@ struct kv_pair
const ValueType value; /* the value of the name */
};
+/* Alias of the first type, ignoring the second. */
+template<typename T1, typename T2>
+using first_type = T1;
+
#else
struct _dont_use_rtx_here_;
diff --git a/gcc/recog.h b/gcc/recog.h
index 0a71a02c4a9..d674d384723 100644
--- a/gcc/recog.h
+++ b/gcc/recog.h
@@ -295,9 +295,10 @@ struct insn_gen_fn
typedef void (*stored_funcptr) (void);
template<typename ...Ts>
- rtx_insn *operator() (Ts... args...) const
+ rtx_insn *operator() (Ts... args) const
{
- return ((rtx_insn *(*) (decltype(args, NULL_RTX)...)) func) (args...);
+ typedef rtx_insn *(*funcptr) (first_type<rtx, Ts>...);
+ return ((funcptr) func) (args...);
}
// This is for compatibility of code that invokes functions like
I get this error on FreeBSD 12.1 with
c++ --version
FreeBSD clang version 8.0.1 (tags/RELEASE_801/final 366581) (based on
LLVM 8.0.1)
Target: x86_64-unknown-freebsd12.1
Thread model: posix
InstalledDir: /usr/bin
In file included from ../../gnu-mirror-gcc-aff95ee/gcc/function.c:51:
../../gnu-mirror-gcc-aff95ee/gcc/recog.h:301:30: error: too many
arguments to function call, expected 1, have 2
return ((funcptr) func) (args...);
~~~~~~~~~~~~~~~~ ^~~~
../../gnu-mirror-gcc-aff95ee/gcc/function.c:3315:29: note: in
instantiation of function template specialization
'insn_gen_fn::operator()<rtx_def *, rtx_def *>' requested here
emit_insn (GEN_FCN (icode) (parmreg, validated_mem));
Thanks for the report. Was clang OK with the earlier version
(i.e. before 4e49b994de060d4a6c9318d0ed52ef038153426e)?
Yes, the last version I built successfully was
b952c2cfcd74c284970e1b9bf1fca58f5f69ab23 on 10th of June. I build GCC
roughly once per week.
Hmm, yeah, can reproduce with a recentish build from clang master:
template<typename T> using int_t = int;
void (*f)();
template<typename ...Ts>
void g(Ts... args) {
#if A
((void (*)(int_t<Ts>...)) f)(args...);
#elif B
typedef void (*funcptr)(decltype((void)args, 0)...);
((funcptr) f)(args...);
#else
typedef void (*funcptr)(int_t<Ts>...);
((funcptr) f)(args...);
#endif
}
void h(int x, int y) { g(x, y); }
Works with -DA and -DB, but fails with the final version.
So it looks like the obvious choices are:
(1) Remove the typedef.
(2) Go back to using decltype.
(3) Revert the whole thing and go back to the overloads.
Not sure about (1), because it leads to awkward formatting, and would
need a comment to say “Don't use a typedef!”. The above error shows
that we're probably close to the edge of what compilers will support
reliably.
That's extremely surprising. It's basic C++11 and so Clang should have
been able to do it 10+ years ago. I'll look into it.
(2) seems to work more reliably, and gives nicer error messages,
but was unpopular for being unidiomatic C++.
I guess at this point, (3) is the way to go.
Yuck, (2) is better than (3).
I'm not massively fond of (2) but (3) is horrible and just unnecessary
with variadics.
