diff --git a/examples/cpp/shift.cpp b/examples/cpp/shift.cpp
index fa7714782..90aeaa595 100644
--- a/examples/cpp/shift.cpp
+++ b/examples/cpp/shift.cpp
@@ -68,7 +68,7 @@ int main() {
 
   // shift
   std::vector<unsigned> params = {
-    4, 2, 32, 8, 2, 32, 8, 4, 2, 2, 8, 8, 4
+    4, 2, 16, 8, 2, 64, 4, 8, 2, 2, 4, 8, 8
   };
   std::ostringstream oss;
   shift.src(oss);
diff --git a/lib/dnn/shift.cpp b/lib/dnn/shift.cpp
index 87b158648..0eae63ddc 100644
--- a/lib/dnn/shift.cpp
+++ b/lib/dnn/shift.cpp
@@ -43,34 +43,24 @@ shift::shift(int B, int NC,
   set_ld(shapes_a_, ld_a_);
   // build LUTs
   build_deltas();
-  build_masks();
 }
 
 void shift::build_deltas() {
+  // compute offset
+  auto offset = [&](unsigned c) {
+    return c*ld_a_[0] + shift_h_[c]*ld_a_[1] + shift_w_[c]*ld_a_[2];
+  };
+  // allocate look-up table
+  size_t TK = 8;
   h_deltas_ = std::vector<int32_t>(512, 0);
-  for(unsigned c = 0; c < NC_; c++){
-    h_deltas_[c] = c*ld_a_[0];
-    h_deltas_[c] += shift_h_[c]*ld_a_[1];
-    h_deltas_[c] += shift_w_[c]*ld_a_[2];
+  // populate look-up table
+  for(unsigned c = 0; c < TK; c++){
+    h_deltas_[c] =  offset(c); // init (shift)
+    h_deltas_[c + 256] = c*ld_a_[0]; // init (no shift)
   }
   for(unsigned c = 0; c < NC_; c++){
-    h_deltas_[c + 256] = c*ld_a_[0];
-  }
-}
-
-void shift::build_masks() {
-  size_t S0 = NC_;
-  size_t S1 = BH_;
-  size_t S2 = BW_;
-  h_masks_.resize(S0*S1*S2);
-  for(size_t ph = 0; ph < S1; ++ph)
-  for(size_t pw = 0; pw < S2; ++pw){
-    int32_t* ptr = &h_masks_[ph*S0 + pw*S0*S1];
-    for(size_t i = 0; i < S0; ++i){
-      bool in_bounds_h = shift_h_[i] + ph >= 0 && shift_h_[i] + ph < BH_;
-      bool in_bounds_w = shift_w_[i] + pw >= 0 && shift_w_[i] + pw < BW_;
-      ptr[i] = in_bounds_h && in_bounds_w;
-    }
+    h_deltas_[TK + c] = offset(c + TK) - offset(c); // deltas (shift)
+    h_deltas_[TK + c + 256] = TK*ld_a_[0]; // deltas (shift)
   }
 }
 
@@ -100,9 +90,7 @@ size_t shift::get_nflops() {
 
 void shift::init(driver::stream *stream, driver::cu_module *module) {
   triton::driver::buffer* delta = ((triton::driver::cu_module*)module)->symbol("delta");
-  triton::driver::buffer* masks = ((triton::driver::cu_module*)module)->symbol("masks");
   stream->write(delta, false, 0, h_deltas_.size()*4, h_deltas_.data());
-  stream->write(masks, false, 0, h_masks_.size()*4, h_masks_.data());
 }
 
 void shift::enqueue(driver::stream *stream, driver::kernel *kernel,
@@ -132,9 +120,10 @@ const tunable int32 TN = {16, 32, 64, 128};
 const tunable int32 TK = {8};
 
 __constant__ int32* delta = alloc_const int32[512];
-__constant__ int32* masks = alloc_const int32[8192];
 
-void shift(restrict read_only fp32 *a, restrict read_only fp32 *b, fp32 *c,
+void shift(restrict read_only align(16) fp32 *a,
+           restrict read_only align(16) fp32 *b,
+           fp32 *c,
            int32 M, int32 N, int32 K,
            int32 ABS, int32 AH, int32 AW, int32 AR, int32 AS) {
   int32 rxa[TM] = get_global_range[TM](0);
@@ -142,7 +131,6 @@ void shift(restrict read_only fp32 *a, restrict read_only fp32 *b, fp32 *c,
   int32 rka[TK] = 0 ... TK;
   int32 rkb[TK] = 0 ... TK;
   fp32 C[TM, TN] = 0;
-  fp32* pxa[TM, TK] = a + rxa[:, newaxis];
   fp32* pb[TN, TK] = b + rkb[newaxis, :]*N + ryb[:, newaxis];
   int32 pad_h = AR/2;
   int32 pad_w = AS/2;
@@ -152,16 +140,17 @@ void shift(restrict read_only fp32 *a, restrict read_only fp32 *b, fp32 *c,
   int32 rah[TM] = rahc % AH;
   int1 maskh[TM] = (rah >= pad_h) && (rah < (AH - pad_h));
   int1 maskw[TM] = (raw >= pad_w) && (raw < (AW - pad_w));
-  int32 offd[TM] = (maskh && maskw) ? 0 : 256;
+  int1 mask[TM] = maskh && maskw;
+  int32 offd[TM] = mask ? 0 : 256;
   __constant__ int32* pd[TM, TK] = delta + rka[newaxis, :] + offd[:, newaxis];
+  fp32* pa[TM, TK] = a + rxa[:, newaxis] + (*pd);
   for(int32 k = K; k > 0; k = k - TK){
-    int32 delta[TM, TK] = *pd;
-    fp32 *pa[TM, TK] = pxa + delta;
     fp32 a[TM, TK] = *pa;
     fp32 b[TN, TK] = *pb;
     C = dot(a, trans(b), C);
     pb = pb + TK*N;
     pd = pd + TK;
+    pa = pa + (*pd);
   }
   int32 rxc[TM] = get_global_range[TM](0);
   int32 ryc[TN] = get_global_range[TN](1);