Nsimd: New package (#14226)

* Nsimd: New package

* Various cleanups as suggested during review

var/spack/repos/builtin/packages/nsimd/package.py

@@ -0,0 +1,65 @@
+# Copyright 2013-2019 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class Nsimd(CMakePackage):
+    """NSIMD is a vectorization library that abstracts SIMD programming.
+    It was designed to exploit the maximum power of processors
+    at a low development cost."""
+
+    homepage = "https://agenium-scale.github.io/nsimd/"
+    url      = "https://github.com/agenium-scale/nsimd/archive/v1.0.tar.gz"
+
+    maintainers = ['eschnett']
+
+    version('1.0', sha256='523dae83f1d93eab30114321f1c9a67e2006a52595da4c51f121ca139abe0857')
+
+    variant('simd',
+            default='none',
+            description='SIMD instruction set',
+            values=(
+                'none',
+                'CPU',
+                'SSE2', 'SSE42', 'AVX', 'AVX2', 'AVX512_KNL', 'AVX512_SKYLAKE',
+                'NEON128', 'AARCH64', 'SVE',
+            ),
+            multi=False)
+    variant('optionals',
+            default=(),
+            description='Optional SIMD features',
+            values=('FMA', 'FP16'),
+            multi=True)
+
+    conflicts('simd=none', msg="SIMD instruction set not defined")
+
+    # Requires a C++14 compiler for building.
+    # The C++ interface requires a C++11 compiler to use.
+    depends_on('cmake@2.8.7:', type='build')
+    depends_on('python@3:', type='build')
+
+    # Add a 'generate_code' phase in the beginning
+    phases = ['generate_code'] + CMakePackage.phases
+
+    def generate_code(self, spec, prefix):
+        """Auto-generates code in the build directory"""
+        options = [
+            'egg/hatch.py',
+            '--all',
+            '--force',
+            '--disable-clang-format',
+        ]
+        python = spec['python'].command
+        python(*options)
+
+    def cmake_args(self):
+        simd = self.spec.variants['simd'].value
+        optionals = ';'.join(self.spec.variants['optionals'].value)
+        cmake_args = [
+            "-DSIMD={0}".format(simd),
+            "-DSIMD_OPTIONALS={0}".format(optionals),
+        ]
+        return cmake_args