diff --git a/examples/matrix.cpp b/examples/matrix.cpp
index a6fb5c168..03d206ba0 100644
--- a/examples/matrix.cpp
+++ b/examples/matrix.cpp
@@ -31,19 +31,21 @@ extern translation_unit *ast_root;
 const char src[] =
 "\
 void test(fp32 *a, fp32 *b, fp32 *c, int32 M, int32 N, int32 K){\
-  int32 rx[16] = get_global_range[16](0);\
-  int32 ry[16] = get_global_range[16](1);\
+  int32 rxa[16] = get_global_range[16](0);\
+  int32 ryb[16] = get_global_range[16](1);\
   int32 rka[8] = 0 ... 8;\
   int32 rkb[8] = 0 ... 8;\
+  int32 rxc[16] = get_global_range[16](0);\
+  int32 ryc[16] = get_global_range[16](1);\
   fp32 C[16, 16] = 0;\
   int32 k;\
-  fp32* pa[16, 8] = a + rx[:, newaxis] + rka[newaxis, :]*M;\
-  fp32* pb[16, 8] = b + ry[:, newaxis] + rkb[newaxis, :]*K;\
-  fp32* pc[16, 16] = c + rx[:, newaxis] + ry[newaxis, :]*M;\
+  fp32* pa[16, 8] = a + rxa[:, newaxis] + rka[newaxis, :]*M;\
+  fp32* pb[16, 8] = b + ryb[:, newaxis] + rkb[newaxis, :]*K;\
+  fp32* pc[16, 16] = c + rxc[:, newaxis] + ryc[newaxis, :]*M;\
   for(k = K; k > 0; k = k - 8){\
     fp32 a[16, 8] = *pa;\
     fp32 b[16, 8] = *pb;\
-    C = C + 1;\
+    C = dot(a, b, C);\
     pa = pa + 8*M;\
     pb = pb + 8*K;\
   }\
@@ -127,6 +129,17 @@ static void compile_machine_code(CUdevice &device, CUcontext &context, CUmodule
   checkCudaErrors(cuModuleGetFunction(&function, module, name.c_str()));
 }
 
+template<class T>
+void simple_gemm(std::vector<T> &c, const std::vector<T> &a, const std::vector<T> &b, size_t M, size_t N, size_t K){
+  for(size_t m = 0; m < M; m++)
+  for(size_t n = 0; n < N; n++){
+    T acc = 0;
+    for(size_t k = 0; k < K; k++)
+      acc += a[m + k*M] * b[n + k*N];
+    c[m + n*M] = acc;
+  }
+}
+
 int main() {
   // create AST from Triton-C source
   YY_BUFFER_STATE buffer = yy_scan_string(src);
@@ -151,14 +164,18 @@ int main() {
   // tuning parameters
   tune.run(module);
   std::vector<unsigned> params = {
-    // asm
+    // a0
     2, 8, 1,
-    // bsn
+    // b0
     4, 4, 1,
-    // pa
+    // c0
+    2, 8, 1,
+    // c1
+    4, 4, 1,
+    // a1
     2, 4, 1,
-    // pb
-    1, 8, 1,
+    // b1
+    1, 8, 1
   };
   std::map<tdl::ir::value*, std::vector<std::string>> errors;
   unsigned i = 0;
@@ -194,12 +211,14 @@ int main() {
   CUstream cu_stream;
   int major, minor;
   compile_machine_code(cu_device, cu_context, cu_module, cu_kernel, cu_stream, major, minor, src, "test");
+//  std::cout << src << std::endl;
 
   // execute machine code
   // Allocate buffers
   typedef float numeric_t;
-  size_t M = 256, N = 256, K = 256;
+  size_t M = 32, N = 32, K = 32;
   std::vector<numeric_t> c(M*N);
+  std::vector<numeric_t> rc(M*N);
   std::vector<numeric_t> a(M*K);
   std::vector<numeric_t> b(K*N);
   for(size_t i = 0; i < a.size(); i++)
@@ -222,14 +241,13 @@ int main() {
   cuFuncGetAttribute(&num_regs, CU_FUNC_ATTRIBUTE_NUM_REGS, cu_kernel);
   unsigned TM = 16;
   unsigned TN = 16;
-  unsigned nthreads = params[1]*params[2]*params[7]*params[8];
+  unsigned nthreads = 32;
   checkCudaErrors(cuLaunchKernel(cu_kernel, M/TM, N/TN, 1, nthreads, 1, 1, 0, cu_stream, args, NULL));
   checkCudaErrors(cuStreamSynchronize(cu_stream));
   // Write back
   checkCudaErrors(cuMemcpyDtoH(c.data(), d_c, sizeof(numeric_t) * c.size()));
-
-  std::cout << c[0] << " " << c[1] << " " << c[2] << " " << c[3] << std::endl;
-//  for(size_t i = 0; i < M*N; i++)
-//    if(c[i] != 32)
-//      std::cout << i << " " << "success" << std::endl;
+  simple_gemm(rc, a, b, M, N, K);
+  for(size_t i = 0; i < M*N; i++)
+    if(std::abs(c[i] - rc[i])/std::max(c[i], rc[i]) > 1e-4)
+      std::cout << i << " " << c[i] << " " << rc[i] << std::endl;
 }
diff --git a/lib/codegen/selection.cpp b/lib/codegen/selection.cpp
index d4d6394a1..1f29275f9 100644
--- a/lib/codegen/selection.cpp
+++ b/lib/codegen/selection.cpp
@@ -317,6 +317,7 @@ void selection::create_tile(ir::value *v, IRBuilder<> &builder,
   if(is_shared){
     size_t offset = alloc_->get_offset(v);
     Value *ptr = builder.CreateGEP(sh_mem_ptr, builder.getInt32(offset));
+    ptr = builder.CreateBitCast(ptr, ty->getPointerTo(ptr->getType()->getPointerAddressSpace()));
     tmap_.insert({v, new shared_tile(ty, shapes, ptr, builder)});
   }
   // create distributed tile
@@ -445,6 +446,7 @@ void selection::lower_tile_instruction(ir::instruction *ins, llvm::IRBuilder<> &
       ir::value *A = ins->get_operand(0);
       ir::value *B = ins->get_operand(1);
       ir::value *C = ins->get_operand(2);
+      Function *f_mul_add = Intrinsic::getDeclaration(module, Intrinsic::fmuladd, {llvm_type(C->get_type()->get_scalar_ty(), ctx)});
       result->for_each([&](indices_t idx){
         Value *res = tmap_.at(C)->get_value(idx);
         unsigned NK = A->get_type()->get_tile_shapes()[1];
@@ -453,7 +455,7 @@ void selection::lower_tile_instruction(ir::instruction *ins, llvm::IRBuilder<> &
           indices_t b_idx = {idx[1], builder.getInt32(K)};
           Value *a = tmap_.at(A)->get_value(a_idx);
           Value *b = tmap_.at(B)->get_value(b_idx);
-          res = builder.CreateAdd(res, builder.CreateMul(a, b));
+          res = builder.CreateCall(f_mul_add, {a, b, res});
         }
         result->set_value(idx, res);
       });