samples: add Terra samples

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

samples/Terra/cudaagg.t

@@ -0,0 +1,56 @@
+if not terralib.cudacompile then
+	print("CUDA not enabled, not performing test...")
+	return
+end
+
+local tid = cudalib.nvvm_read_ptx_sreg_tid_x--terralib.intrinsic("llvm.nvvm.read.ptx.sreg.tid.x",{} -> int)
+local ntid = cudalib.nvvm_read_ptx_sreg_ntid_x -- terralib.intrinsic("llvm.nvvm.read.ptx.sreg.ntid.x",{} -> int)
+
+
+struct OneFloat {
+    a : int;
+}
+
+fn = terra(result : &float, bar : int[5])
+	result[tid()] = bar[0] + bar[1] + bar[2] + bar[3] + bar[4]
+end
+fn:setinlined(false)
+
+--our very simple cuda kernel
+--more work needs to be done to expose the right CUDA intrinsics
+--to do more complicated things
+foo = terra(result : &float)
+    fn(result, array(tid(),tid()+1,tid()+2,tid()+3,tid()+4) )
+end
+
+terralib.includepath = terralib.includepath..";/usr/local/cuda/include"
+
+local C = terralib.includecstring [[
+#include "cuda_runtime.h"
+#include <stdlib.h>
+#include <stdio.h>
+]]
+local R = terralib.cudacompile({ bar = foo })
+
+terra doit(N : int)
+	var data : &float
+	C.cudaMalloc([&&opaque](&data),sizeof(float)*N)
+	var launch = terralib.CUDAParams { 1,1,1, N,1,1, 0, nil }
+	R.bar(&launch,data)
+	var results : &float = [&float](C.malloc(sizeof(float)*N))
+	C.cudaMemcpy(results,data,sizeof(float)*N,2)
+	var result = 0.f
+	for i = 0,N do
+		result = result + results[i]
+	end
+	return result
+end
+
+local test = require("test")
+local N = 16
+
+function s(n) return (n - 1) * n / 2 end
+function ex(i) return s(N+i) - s(i) end
+local expected = ex(0) + ex(1) + ex(2) + ex(3) + ex(4)
+test.eq(doit(N),expected)
+