cmd/compile: optimize SIMD IsNaN.Or(IsNaN)

IsNaN's underlying instruction, VCMPPS (or VCMPPD), takes two
inputs, and computes either of them is NaN. Optimize the Or
pattern to generate two-operand form.

This implements the optimization mentioned in CL 733660.

Change-Id: I13943b377ee384864c913eed320763f333a03e41
Reviewed-on: https://go-review.googlesource.com/c/go/+/733680
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/src/simd/archsimd/internal/simd_test/compare_test.go b/src/simd/archsimd/internal/simd_test/compare_test.go
index e678676be0..ea8514ac93 100644
--- a/src/simd/archsimd/internal/simd_test/compare_test.go
+++ b/src/simd/archsimd/internal/simd_test/compare_test.go
@@ -309,4 +309,38 @@ func TestIsNaN(t *testing.T) {
 		testFloat32x16UnaryCompare(t, archsimd.Float32x16.IsNaN, isNaNSlice[float32])
 		testFloat64x8UnaryCompare(t, archsimd.Float64x8.IsNaN, isNaNSlice[float64])
 	}
+
+	// Test x.IsNaN().Or(y.IsNaN()), which is optimized to VCMPP(S|D) $3, x, y.
+	want32 := mapCompare(func(x, y float32) bool { return x != x || y != y })
+	want64 := mapCompare(func(x, y float64) bool { return x != x || y != y })
+	testFloat32x4Compare(t,
+		func(x, y archsimd.Float32x4) archsimd.Mask32x4 {
+			return x.IsNaN().Or(y.IsNaN())
+		}, want32)
+	testFloat64x2Compare(t,
+		func(x, y archsimd.Float64x2) archsimd.Mask64x2 {
+			return x.IsNaN().Or(y.IsNaN())
+		}, want64)
+
+	if archsimd.X86.AVX2() {
+		testFloat32x8Compare(t,
+			func(x, y archsimd.Float32x8) archsimd.Mask32x8 {
+				return x.IsNaN().Or(y.IsNaN())
+			}, want32)
+		testFloat64x4Compare(t,
+			func(x, y archsimd.Float64x4) archsimd.Mask64x4 {
+				return x.IsNaN().Or(y.IsNaN())
+			}, want64)
+	}
+
+	if archsimd.X86.AVX512() {
+		testFloat32x16Compare(t,
+			func(x, y archsimd.Float32x16) archsimd.Mask32x16 {
+				return x.IsNaN().Or(y.IsNaN())
+			}, want32)
+		testFloat64x8Compare(t,
+			func(x, y archsimd.Float64x8) archsimd.Mask64x8 {
+				return x.IsNaN().Or(y.IsNaN())
+			}, want64)
+	}
 }