samples: add Terra samples

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

samples/Terra/cudaatomic.t

@@ -0,0 +1,39 @@
+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)
+
+foo = terra(result : &int)
+    var t = tid()
+    terralib.asm(terralib.types.unit,"red.global.max.u32 [$0], $1;","l,r",true,result,t)
+end
+
+terralib.includepath = terralib.includepath..";/usr/local/cuda/include"
+
+
+local C = terralib.includecstring [[
+#include "cuda_runtime.h"
+#include <stdlib.h>
+#include <stdio.h>
+]]
+
+sync = terralib.externfunction("cudaThreadSynchronize", {} -> int)
+
+local R = terralib.cudacompile({ bar = foo },true)
+
+terra doit(N : int)
+    var data = 0
+    var location : &int
+    C.cudaMalloc([&&opaque](&location),sizeof(int))
+    C.cudaMemcpy(location,&data,sizeof(int),1)
+    
+	var launch = terralib.CUDAParams { 1,1,1, N,1,1, 0, nil }
+	R.bar(&launch,location)
+	var data2 = -1
+	C.cudaMemcpy(&data2,location,sizeof(int),2)
+    return data2
+end
+
+assert(doit(32) == 31)