samples: add Terra samples

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

samples/Terra/dgemmpaper.t

@@ -0,0 +1,75 @@
+
+function symmat(name,I,...)
+  if not I then return symbol(name) end
+  local r = {}
+  for i = 0,I-1 do
+    r[i] = symmat(name..tostring(i),...)
+  end
+  return r
+end
+prefetch = terralib.intrinsic("llvm.prefetch",{&opaque,int,int,int} -> {})
+
+
+function genkernel(NB, RM, RN, V,alpha)
+  local A,B,C = symbol("A"),symbol("B"),symbol("C")
+  local mm,nn = symbol("mn"),symbol("nn")
+  local lda,ldb,ldc = symbol("lda"),symbol("ldb"),symbol("ldc")
+  local a,b = symmat("a",RM), symmat("b",RN)
+  local c,caddr = symmat("c",RM,RN), symmat("caddr",RM,RN)
+  local k = symbol("k")
+  local loadc,storec = terralib.newlist(),terralib.newlist()
+  local VT = vector(double,V)
+  local VP = &VT
+  for m = 0, RM-1 do for n = 0, RN-1 do
+      loadc:insert(quote
+        var [caddr[m][n]] = C + m*ldc + n*V
+        var [c[m][n]] = 
+          alpha * @VP([caddr[m][n]])
+      end)
+      storec:insert(quote
+        @VP([caddr[m][n]]) = [c[m][n]]
+      end)
+  end end
+  local calcc = terralib.newlist()
+  for n = 0, RN-1 do
+    calcc:insert(quote
+      var [b[n]] = @VP(&B[n*V])
+    end)
+  end
+  for m = 0, RM-1 do
+    calcc:insert(quote
+      var [a[m]] = VT(A[m*lda])
+    end)
+  end
+  for m = 0, RM-1 do for n = 0, RN-1 do
+      calcc:insert(quote
+        [c[m][n]] = [c[m][n]] + [a[m]] * [b[n]]
+      end) 
+  end end
+  return terra([A] : &double, [B] : &double, [C] : &double,
+               [lda] : int64,[ldb] : int64,[ldc] : int64)
+    for [mm] = 0, NB, RM do
+      for [nn] = 0, NB, RN*V do
+        [loadc];
+        for [k] = 0, NB do
+          prefetch(B + 4*ldb,0,3,1);
+          [calcc];
+          B,A = B + ldb,A + 1
+        end
+        [storec];
+        A,B,C = A - NB,B - ldb*NB + RN*V,C + RN*V
+      end
+      A,B,C = A + lda*RM, B - NB, C + RM * ldb - NB
+    end
+  end
+end
+
+local a = genkernel(40,4,2,8,1)
+a:compile()
+a:printpretty()
+
+terra short_saxpy(a : float, 
+      x : vector(float,4), y : vector(float,4))
+    return a*x + y
+end
+short_saxpy:printpretty()