Add complex-norm benchmark

ChangeLog:

	* benchtests/Makefile:
	* benchtests/complex-norm.cpp: New file.

Author: mattkretz

benchtests/Makefile

@@ -4,12 +4,15 @@
 
 benchmarks=$(patsubst %.cpp,%,$(wildcard *.cpp))
 archs=native ivybridge westmere x86-64
-CXXFLAGS=-g0 -O2 -std=gnu++26 -Wall -Wextra -Wno-psabi -fmax-errors=2 -DVIR_NEXT_PATCH -DVIR_EXTENSIONS
+CXXFLAGS=-g0 -O2 -std=gnu++26 -Wall -Wextra -Wno-psabi -fmax-errors=2 -D VIR_PATCH_MATH -DVIR_EXTENSIONS
 
 fastmath=-ffast-math
 default=
+improve_cx1=-DVIR_PATCH_IMPROVE_CX=1
+improve_cx2=-DVIR_PATCH_IMPROVE_CX=2
+improve_cx3=-DVIR_PATCH_IMPROVE_CX=3
 
-variants=default fastmath
+variants=default fastmath improve_cx1 improve_cx2 improve_cx3
 
 all: all-targets
 

benchtests/complex-norm.cpp

@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/* Copyright © 2019–2026 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH
+ *                       Matthias Kretz <m.kretz@gsi.de>
+ */
+
+#include "bench.h"
+#include <climits>
+#include <complex>
+
+template <int Special>
+  struct Benchmark<Special>
+  {
+    template <typename T>
+      static constexpr bool accept
+	= complex_like<T>
+	    or (simd_vec_type<T> and requires { requires T::abi_type::_S_is_cx_ileav; });
+
+    static constexpr Info<2> info = {"Latency", "Throughput"};
+
+    template <simd_vec_type T>
+      [[gnu::always_inline]]
+      static void
+      d_from_r(T& d, simd_vec_type auto& r)
+      {
+	vir::fake_modify(r);
+	d = std::bit_cast<T>(cat(r, r));
+	vir::fake_modify(d);
+      }
+
+    template <complex_like T>
+      [[gnu::always_inline]]
+      static void
+      d_from_r(T& d, typename T::value_type& r)
+      {
+	vir::fake_modify(r);
+	d = {r, r};
+	vir::fake_modify(d);
+      }
+
+
+    template <class T>
+      [[gnu::flatten]]
+      static Times<info.size()>
+      run()
+      {
+	using TT = value_type_t<T>;
+	using TTT = typename TT::value_type;
+
+	constexpr TT init = TT(1, 0);
+
+	T zerov = T();
+	T b = zerov + TT(TTT(0), TTT(1));
+	vir::fake_modify(zerov, b);
+
+	T data[6];
+	for (T& a : data)
+	  {
+	    a = zerov + init;
+	    vir::fake_modify(a);
+	  }
+
+	return {
+	  0.25 * time_median([&] [[gnu::always_inline]] {
+		   auto d = b;
+		   using std::norm;
+		   auto r = norm(d); d_from_r(d, r);
+		   r = norm(d); d_from_r(d, r);
+		   r = norm(d); d_from_r(d, r);
+		   r = norm(d); d_from_r(b, r);
+		 }),
+	  1./6. * time_median([&] [[gnu::always_inline]] {
+		    auto d0 = data[0]; vir::fake_modify(d0); auto r0 = std::norm(d0);
+		    auto d1 = data[1]; vir::fake_modify(d1); auto r1 = std::norm(d1);
+		    auto d2 = data[2]; vir::fake_modify(d2); auto r2 = std::norm(d2);
+		    auto d3 = data[3]; vir::fake_modify(d3); auto r3 = std::norm(d3);
+		    auto d4 = data[4]; vir::fake_modify(d4); auto r4 = std::norm(d4);
+		    auto d5 = data[5]; vir::fake_modify(d5); auto r5 = std::norm(d5);
+		    vir::fake_read(r0, r1, r2, r3, r4, r5);
+		  })
+	};
+      }
+  };
+
+void
+bench_main()
+{
+  //bench_all<std::complex<std::float16_t>>();
+  bench_all<std::complex<float>>();
+  bench_all<std::complex<double>>();
+}