From: Hongyu Wang <hongyu.wang@intel.com>
Date: Mon, 11 Dec 2023 01:15:02 +0000 (+0800)
Subject: i386: Sync move_max/store_max with prefer-vector-width [PR112824]
X-Git-Tag: basepoints/gcc-15~3564
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a52940cfee0908aed0d2a674a451f6d99844444d;p=thirdparty%2Fgcc.git

i386: Sync move_max/store_max with prefer-vector-width [PR112824]

Currently move_max follows the tuning feature first, but ideally it
should sync with prefer-vector-width when it is explicitly set to keep
vector move and operation with same vector size.

gcc/ChangeLog:

	PR target/112824
	* config/i386/i386-options.cc (ix86_option_override_internal):
	Sync ix86_move_max/ix86_store_max with prefer_vector_width when
	it is explicitly set.

gcc/testsuite/ChangeLog:

	PR target/112824
	* gcc.target/i386/pieces-memset-45.c: Remove
	-mprefer-vector-width=256.
	* g++.target/i386/pr112824-1.C: New test.
---

diff --git a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc
index 588a0878c0df..440ef59ffff3 100644
--- a/gcc/config/i386/i386-options.cc
+++ b/gcc/config/i386/i386-options.cc
@@ -3012,7 +3012,9 @@ ix86_option_override_internal (bool main_args_p,
     {
       /* Set the maximum number of bits can be moved from memory to
 	 memory efficiently.  */
-      if (ix86_tune_features[X86_TUNE_AVX512_MOVE_BY_PIECES])
+      if (opts_set->x_prefer_vector_width_type != PVW_NONE)
+	opts->x_ix86_move_max = opts->x_prefer_vector_width_type;
+      else if (ix86_tune_features[X86_TUNE_AVX512_MOVE_BY_PIECES])
 	opts->x_ix86_move_max = PVW_AVX512;
       else if (ix86_tune_features[X86_TUNE_AVX256_MOVE_BY_PIECES])
 	opts->x_ix86_move_max = PVW_AVX256;
@@ -3034,7 +3036,9 @@ ix86_option_override_internal (bool main_args_p,
     {
       /* Set the maximum number of bits can be stored to memory
 	 efficiently.  */
-      if (ix86_tune_features[X86_TUNE_AVX512_STORE_BY_PIECES])
+      if (opts_set->x_prefer_vector_width_type != PVW_NONE)
+	opts->x_ix86_store_max = opts->x_prefer_vector_width_type;
+      else if (ix86_tune_features[X86_TUNE_AVX512_STORE_BY_PIECES])
 	opts->x_ix86_store_max = PVW_AVX512;
       else if (ix86_tune_features[X86_TUNE_AVX256_STORE_BY_PIECES])
 	opts->x_ix86_store_max = PVW_AVX256;
diff --git a/gcc/testsuite/g++.target/i386/pr112824-1.C b/gcc/testsuite/g++.target/i386/pr112824-1.C
new file mode 100644
index 000000000000..159cafe208ba
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/pr112824-1.C
@@ -0,0 +1,110 @@
+/* PR target/112824 */
+/* { dg-do compile } */
+/* { dg-options "-std=c++23 -O3 -march=skylake-avx512 -mprefer-vector-width=512" } */
+/* { dg-final { scan-assembler-not "vmov(?:dqu|apd)\[ \\t\]+\[^\n\]*%ymm" } } */
+
+#include <bit>
+#include <concepts>
+#include <cstddef>
+#include <cstdint>
+
+template <ptrdiff_t W, typename T>
+using Vec [[gnu::vector_size(W * sizeof(T))]] = T;
+
+// Omitted: 16 without AVX, 32 without AVX512F,
+// or for forward compatibility some AVX10 may also mean 32-only
+static constexpr ptrdiff_t VectorBytes = 64;
+template<typename T>
+static constexpr ptrdiff_t VecWidth = 64 <= sizeof(T) ? 1 : 64/sizeof(T);
+
+template <typename T, ptrdiff_t N> struct Vector{
+    static constexpr ptrdiff_t L = N;
+    T data[L];
+    static constexpr auto size()->ptrdiff_t{return N;}
+};
+template <std::floating_point T, ptrdiff_t N> struct Vector<T,N>{
+    static constexpr ptrdiff_t W = N >= VecWidth<T> ? VecWidth<T> : ptrdiff_t(std::bit_ceil(size_t(N))); 
+    static constexpr ptrdiff_t L = (N/W) + ((N%W)!=0);
+    using V = Vec<W,T>;
+    V data[L];
+    static constexpr auto size()->ptrdiff_t{return N;}
+};
+/// should be trivially copyable
+/// codegen is worse when passing by value, even though it seems like it should make
+/// aliasing simpler to analyze?
+template<typename T, ptrdiff_t N>
+[[gnu::always_inline]] constexpr auto operator+(Vector<T,N> x, Vector<T,N> y) -> Vector<T,N> {
+    Vector<T,N> z;
+    for (ptrdiff_t n = 0; n < Vector<T,N>::L; ++n) z.data[n] = x.data[n] + y.data[n];
+    return z;
+}
+template<typename T, ptrdiff_t N>
+[[gnu::always_inline]] constexpr auto operator*(Vector<T,N> x, Vector<T,N> y) -> Vector<T,N> {
+    Vector<T,N> z;
+    for (ptrdiff_t n = 0; n < Vector<T,N>::L; ++n) z.data[n] = x.data[n] * y.data[n];
+    return z;
+}
+template<typename T, ptrdiff_t N>
+[[gnu::always_inline]] constexpr auto operator+(T x, Vector<T,N> y) -> Vector<T,N> {
+    Vector<T,N> z;
+    for (ptrdiff_t n = 0; n < Vector<T,N>::L; ++n) z.data[n] = x + y.data[n];
+    return z;
+}
+template<typename T, ptrdiff_t N>
+[[gnu::always_inline]] constexpr auto operator*(T x, Vector<T,N> y) -> Vector<T,N> {
+    Vector<T,N> z;
+    for (ptrdiff_t n = 0; n < Vector<T,N>::L; ++n) z.data[n] = x * y.data[n];
+    return z;
+}
+
+template <typename T, ptrdiff_t N> struct Dual {
+  T value;
+  Vector<T, N> partials;
+};
+// Here we have a specialization for non-power-of-2 `N`
+template <typename T, ptrdiff_t N> 
+requires(std::floating_point<T> && (std::popcount(size_t(N))>1))
+struct Dual<T,N> {
+  Vector<T, N+1> data;
+};
+
+template<ptrdiff_t W, typename T>
+consteval auto firstoff(){
+    static_assert(std::same_as<T,double>, "type not implemented");
+    if constexpr (W==2) return Vec<2,int64_t>{0,1} != 0;
+    else if constexpr (W == 4) return Vec<4,int64_t>{0,1,2,3} != 0;
+    else if constexpr (W == 8) return Vec<8,int64_t>{0,1,2,3,4,5,6,7} != 0;
+    else static_assert(false, "vector width not implemented");
+}
+
+template <typename T, ptrdiff_t N>
+[[gnu::always_inline]] constexpr auto operator+(Dual<T, N> a,
+                                                Dual<T, N> b)
+  -> Dual<T, N> {
+  if constexpr (std::floating_point<T> && (std::popcount(size_t(N))>1)){
+    Dual<T,N> c;
+    for (ptrdiff_t l = 0; l < Vector<T,N>::L; ++l)
+      c.data.data[l] = a.data.data[l] + b.data.data[l]; 
+    return c;
+  } else return {a.value + b.value, a.partials + b.partials};
+}
+
+template <typename T, ptrdiff_t N>
+[[gnu::always_inline]] constexpr auto operator*(Dual<T, N> a,
+                                                Dual<T, N> b)
+  -> Dual<T, N> {
+  if constexpr (std::floating_point<T> && (std::popcount(size_t(N))>1)){
+    using V = typename Vector<T,N>::V;
+    V va = V{}+a.data.data[0][0], vb = V{}+b.data.data[0][0];
+    V x = va * b.data.data[0];
+    Dual<T,N> c;
+    c.data.data[0] = firstoff<Vector<T,N>::W,T>() ? x + vb*a.data.data[0] : x;
+    for (ptrdiff_t l = 1; l < Vector<T,N>::L; ++l)
+      c.data.data[l] = va*b.data.data[l] + vb*a.data.data[l]; 
+    return c;
+  } else return {a.value * b.value, a.value * b.partials + b.value * a.partials};
+}
+
+void prod(Dual<Dual<double,7>,2> &c, const Dual<Dual<double,7>,2> &a, const Dual<Dual<double,7>,2>&b){
+    c = a*b;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pieces-memset-45.c b/gcc/testsuite/gcc.target/i386/pieces-memset-45.c
index 70c80e5064b7..e8ce7c23256f 100644
--- a/gcc/testsuite/gcc.target/i386/pieces-memset-45.c
+++ b/gcc/testsuite/gcc.target/i386/pieces-memset-45.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -march=x86-64 -mprefer-vector-width=256 -mavx512f -mtune-ctrl=avx512_store_by_pieces" } */
+/* { dg-options "-O2 -march=x86-64 -mavx512f -mtune-ctrl=avx512_store_by_pieces" } */
 
 extern char *dst;