[gcc/devel/gccgo] recog: Use parameter packs for operator()

[Ian Lance Taylor]

https://gcc.gnu.org/g:3a179232a743b2b1987b21034cd5bb3bc660ee85

commit 3a179232a743b2b1987b21034cd5bb3bc660ee85
Author: Richard Sandiford <richard.sandiford@arm.com>
Date:   Fri Jun 12 08:16:48 2020 +0100

    recog: Use parameter packs for operator()
    
    This patch uses parameter packs to define insn_gen_fn::operator().
    I guess in some ways it's C++-ification for its own sake, but it does
    make things simpler and removes the current artificial limit of 16
    arguments.
    
    Note that the call is still strongly typed: all arguments have to have
    implicit conversions to rtx.  Error messages for bad arguments look
    reasonable.
    
    I'm sure there are more elegant ways of getting the function type,
    but this version at least fits on one line, so I didn't try too
    hard to find an alternative.
    
    2020-06-12  Richard Sandiford  <richard.sandiford@arm.com>
    
    gcc/
            * recog.h (insn_gen_fn::f0, insn_gen_fn::f1, insn_gen_fn::f2)
            (insn_gen_fn::f3, insn_gen_fn::f4, insn_gen_fn::f5, insn_gen_fn::f6)
            (insn_gen_fn::f7, insn_gen_fn::f8, insn_gen_fn::f9, insn_gen_fn::f10)
            (insn_gen_fn::f11, insn_gen_fn::f12, insn_gen_fn::f13)
            (insn_gen_fn::f14, insn_gen_fn::f15, insn_gen_fn::f16): Delete.
            (insn_gen_fn::operator()): Replace overloaded definitions with
            a parameter-pack version.

Diff:
---
 gcc/recog.h | 40 +++++-----------------------------------
 1 file changed, 5 insertions(+), 35 deletions(-)

diff --git a/gcc/recog.h b/gcc/recog.h
index 17c09fdba3b..0a71a02c4a9 100644
--- a/gcc/recog.h
+++ b/gcc/recog.h
@@ -292,43 +292,13 @@ typedef const char * (*insn_output_fn) (rtx *, rtx_insn *);
 
 struct insn_gen_fn
 {
-  typedef rtx_insn * (*f0) (void);
-  typedef rtx_insn * (*f1) (rtx);
-  typedef rtx_insn * (*f2) (rtx, rtx);
-  typedef rtx_insn * (*f3) (rtx, rtx, rtx);
-  typedef rtx_insn * (*f4) (rtx, rtx, rtx, rtx);
-  typedef rtx_insn * (*f5) (rtx, rtx, rtx, rtx, rtx);
-  typedef rtx_insn * (*f6) (rtx, rtx, rtx, rtx, rtx, rtx);
-  typedef rtx_insn * (*f7) (rtx, rtx, rtx, rtx, rtx, rtx, rtx);
-  typedef rtx_insn * (*f8) (rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx);
-  typedef rtx_insn * (*f9) (rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx);
-  typedef rtx_insn * (*f10) (rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx);
-  typedef rtx_insn * (*f11) (rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx);
-  typedef rtx_insn * (*f12) (rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx);
-  typedef rtx_insn * (*f13) (rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx);
-  typedef rtx_insn * (*f14) (rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx);
-  typedef rtx_insn * (*f15) (rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx);
-  typedef rtx_insn * (*f16) (rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx);
-
   typedef void (*stored_funcptr) (void);
 
-  rtx_insn * operator () (void) const { return ((f0)func) (); }
-  rtx_insn * operator () (rtx a0) const { return ((f1)func) (a0); }
-  rtx_insn * operator () (rtx a0, rtx a1) const { return ((f2)func) (a0, a1); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2) const { return ((f3)func) (a0, a1, a2); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3) const { return ((f4)func) (a0, a1, a2, a3); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3, rtx a4) const { return ((f5)func) (a0, a1, a2, a3, a4); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3, rtx a4, rtx a5) const { return ((f6)func) (a0, a1, a2, a3, a4, a5); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3, rtx a4, rtx a5, rtx a6) const { return ((f7)func) (a0, a1, a2, a3, a4, a5, a6); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3, rtx a4, rtx a5, rtx a6, rtx a7) const { return ((f8)func) (a0, a1, a2, a3, a4, a5, a6, a7); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3, rtx a4, rtx a5, rtx a6, rtx a7, rtx a8) const { return ((f9)func) (a0, a1, a2, a3, a4, a5, a6, a7, a8); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3, rtx a4, rtx a5, rtx a6, rtx a7, rtx a8, rtx a9) const { return ((f10)func) (a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3, rtx a4, rtx a5, rtx a6, rtx a7, rtx a8, rtx a9, rtx a10) const { return ((f11)func) (a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3, rtx a4, rtx a5, rtx a6, rtx a7, rtx a8, rtx a9, rtx a10, rtx a11) const { return ((f12)func) (a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3, rtx a4, rtx a5, rtx a6, rtx a7, rtx a8, rtx a9, rtx a10, rtx a11, rtx a12) const { return ((f13)func) (a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3, rtx a4, rtx a5, rtx a6, rtx a7, rtx a8, rtx a9, rtx a10, rtx a11, rtx a12, rtx a13) const { return ((f14)func) (a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3, rtx a4, rtx a5, rtx a6, rtx a7, rtx a8, rtx a9, rtx a10, rtx a11, rtx a12, rtx a13, rtx a14) const { return ((f15)func) (a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14); }
-  rtx_insn * operator () (rtx a0, rtx a1, rtx a2, rtx a3, rtx a4, rtx a5, rtx a6, rtx a7, rtx a8, rtx a9, rtx a10, rtx a11, rtx a12, rtx a13, rtx a14, rtx a15) const { return ((f16)func) (a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15); }
+  template<typename ...Ts>
+  rtx_insn *operator() (Ts... args...) const
+  {
+    return ((rtx_insn *(*) (decltype(args, NULL_RTX)...)) func) (args...);
+  }
 
   // This is for compatibility of code that invokes functions like
   //   (*funcptr) (arg)