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.

1 files changed, 5 insertions, 35 deletions

diff --git a/gcc/recog.h b/gcc/recog.h
index 17c09fd..0a71a02 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)