Re: [PATCH] recog: Use parameter packs for operator()

[Sebastian Huber]

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.