samples: add Terra samples

source: https://github.com/zdevito/terra/tree/master/tests

samples/Terra/avxhadd.t

@@ -0,0 +1,32 @@
+local haddavx = terralib.intrinsic("llvm.x86.avx.hadd.ps.256", { vector(float,8), vector(float,8) } -> vector(float,8))
+
+terra hadd(v : vector(float,8))
+	var v1 = haddavx(v,v)
+	var v2 = haddavx(v1,v1)
+	return v2[0] + v2[4]
+end
+
+ffi = require("ffi")
+
+local stdio = terralib.includec("stdio.h")
+
+terra foobar(a : &float)
+	return hadd(@[&vector(float,8)](a))
+end
+
+dat = ffi.new("float[?] __attribute__((aligned(32)))",8)
+
+for i = 1,8 do
+	dat[i-1] = i
+end
+
+if terralib.llvmversion == 31 then
+	print("ignoring...")
+else
+	foobar:compile()
+	local test = require("test")
+	test.eq(foobar(dat),36)
+end
+
+--terralib.saveobj("avxhadd",{main = foobar})
+--os.execute("./avxhadd")