diff --git a/examples/matrix.cpp b/examples/matrix.cpp
index 0baf844dc..1a7484ab0 100644
--- a/examples/matrix.cpp
+++ b/examples/matrix.cpp
@@ -38,61 +38,47 @@ extern translation_unit *ast_root;
 
 const char src[] =
 "\
-__constant__ int32* delta = alloc_const int32[16];\
-__constant__ int32* masks = alloc_const int32[16];\
-\
 const tunable int32 TM;\
 const tunable int32 TN;\
 const tunable int32 TK;\
 \
-void matmul(restrict readonly fp32 *a, restrict readonly fp32 *b, fp32 *c, int32 M, int32 N, int32 K, int32 bound){\
+void matmul(restrict read_only fp32 *a, restrict read_only fp32 *b, fp32 *c,\
+           int32 M, int32 N, int32 K, int32 bound){\
   int32 rxa[TM] = get_global_range[TM](0);\
   int32 ryb[TN] = get_global_range[TN](1);\
   int32 rka[TK] = 0 ... TK;\
   int32 rkb[TK] = 0 ... TK;\
-  int32 rxc[TM];\
-  int32 ryc[TN];\
   fp32 C[TM, TN] = 0;\
-  int32 k;\
   fp32* pa[TM, TK] = a + rka[newaxis, :]*M + rxa[:, newaxis];\
   fp32* pb[TN, TK] = b + rkb[newaxis, :]*K + ryb[:, newaxis];\
-  fp32* pc[TM, TN];\
   fp32 a[TM, TK] = *pa;\
   fp32 b[TN, TK] = *pb;\
-  int1 checkc0[TM];\
-  int1 checkc1[TN];\
-  int1 checkc[TM, TN];\
-   for(k = K; k > 0; k = k - TK){\
-     int1 checka[TM, TK];\
-     int1 checkb[TN, TK];\
-     int1 checka0[TM];\
-     int1 checka1[TK];\
-     int1 checkb0[TN];\
-     int1 checkb1[TK];\
-     C = dot(a, b, C);\
-     pa = pa + TK*M;\
-     pb = pb + TK*K;\
-     checka = k > bound;\
-     checkb = k > bound;\
-     @checka a = *pa;\
-     @checkb b = *pb;\
-     if(k > bound)\
-       continue;\
-     checka0 = rxa < M;\
-     checka1 = rka < k;\
-     checkb0 = ryb < N;\
-     checkb1 = rkb < k;\
-     checka = checka0[:, newaxis] && checka1[newaxis, :];\
-     checkb = checkb0[:, newaxis] && checkb1[newaxis, :];\
-     a = checka ? *pa : 0;\
-     b = checkb ? *pb : 0;\
-   }\
-  rxc = get_global_range[TM](0);\
-  ryc = get_global_range[TN](1);\
-  pc = c + ryc[newaxis, :]*M + rxc[:, newaxis];\
-  checkc0 = rxc < M;\
-  checkc1 = ryc < N;\
-  checkc = checkc0[:, newaxis] && checkc1[newaxis, :];\
+  for(int32 k = K; k > 0;){\
+    C = dot(a, b, C);\
+    pa = pa + TK*M;\
+    pb = pb + TK*K;\
+    k = k - TK;\
+    int1 checka[TM, TK] = k > bound;\
+    int1 checkb[TN, TK] = k > bound;\
+    @checka a = *pa;\
+    @checkb b = *pb;\
+    if(k > bound)\
+      continue;\
+    int1 checka0[TM] = rxa < M;\
+    int1 checka1[TK] = rka < k;\
+    int1 checkb0[TN] = ryb < N;\
+    int1 checkb1[TK] = rkb < k;\
+    checka = checka0[:, newaxis] && checka1[newaxis, :];\
+    checkb = checkb0[:, newaxis] && checkb1[newaxis, :];\
+    a = checka ? *pa : 0;\
+    b = checkb ? *pb : 0;\
+  }\
+  int32 rxc[TM] = get_global_range[TM](0);\
+  int32 ryc[TN] = get_global_range[TN](1);\
+  fp32* pc[TM, TN] = c + ryc[newaxis, :]*M + rxc[:, newaxis];\
+  int1 checkc0[TM] = rxc < M;\
+  int1 checkc1[TN] = ryc < N;\
+  int1 checkc[TM, TN] = checkc0[:, newaxis] && checkc1[newaxis, :];\
   @checkc *pc = C;\
 }\
 ";
diff --git a/include/triton/ast/ast.h b/include/triton/ast/ast.h
index f511ac132..cc77f66b5 100644
--- a/include/triton/ast/ast.h
+++ b/include/triton/ast/ast.h
@@ -323,7 +323,10 @@ public:
 class initializer;
 class declaration_specifier;
 
-class declaration: public node{
+class block_item: public node{
+};
+
+class declaration: public block_item{
 public:
   declaration(node *spec, node *init)
     : spec_((declaration_specifier*)spec), init_((list<initializer*>*)init) { }
@@ -335,10 +338,7 @@ public:
   const list<initializer*> *init_;
 };
 
-class statement: public node{
-
-private:
-  expression *pred_;
+class statement: public block_item{
 };
 
 class expression_statement: public statement{
@@ -353,19 +353,19 @@ private:
   expression *mask_;
 };
 
+
 class compound_statement: public statement{
   typedef list<declaration*>* declarations_t;
   typedef list<statement*>* statements_t;
 
 public:
-  compound_statement(node* decls, node* statements)
-    : decls_((declarations_t)decls), statements_((statements_t)statements) {}
+  compound_statement(node* items)
+    : items_((list<block_item*>*)items){}
 
   ir::value* codegen(ir::module * mod) const;
 
 private:
-  declarations_t decls_;
-  statements_t statements_;
+  list<block_item*>* items_;
 };
 
 class selection_statement: public statement{
@@ -413,7 +413,6 @@ class no_op: public statement { };
 // Types
 class declaration_specifier: public node{
 public:
-  using node::node;
   virtual ir::type* type(ir::module *mod) const = 0;
   virtual std::vector<STORAGE_SPEC_T> storage() const = 0;
 };
diff --git a/include/triton/ast/parser.y b/include/triton/ast/parser.y
index acd31d995..724f4240b 100644
--- a/include/triton/ast/parser.y
+++ b/include/triton/ast/parser.y
@@ -275,21 +275,16 @@ statement
 	;
 
 compound_statement
-  : '{' '}' { $$ = new compound_statement(nullptr, nullptr); }
-  | '{' statement_list '}' { $$ = new compound_statement(nullptr, $2); }
-  | '{' declaration_list '}' { $$ = new compound_statement($2, nullptr); }
-  | '{' declaration_list statement_list '}' { $$ = new compound_statement($2, $3);}
-	;
+    : '{' '}' { $$ = new compound_statement(nullptr); }
+    | '{' block_item_list '}' { $$ = new compound_statement($2); }
 
+block_item_list
+  : block_item { $$ = new list<block_item*>((block_item*)$1); }
+  | block_item_list block_item { $$ = append_ptr_list<block_item>($1, $2); }
 
-declaration_list
-  : declaration { $$ = new list<declaration*>((declaration*)$1); }
-  | declaration_list declaration { $$ = append_ptr_list<declaration>($1, $2); }
-
-statement_list
-  : statement { $$ = new list<statement*>((statement*)$1); }
-  | statement_list statement { $$ = append_ptr_list<statement>($1, $2); }
-	;
+block_item
+  : declaration { $$ = $1; }
+  | statement { $$ = $1; }
 
 expression_statement
 	: ';' { $$ = new no_op(); }
@@ -304,6 +299,8 @@ selection_statement
 
 iteration_statement
   : FOR '(' expression_statement expression_statement expression ')' statement { $$ = new iteration_statement($3, $4, $5, $7); }
+  | FOR '(' declaration expression_statement ')' statement { $$ = new iteration_statement($3, $4, nullptr, $6); }
+  | FOR '(' declaration expression_statement expression ')' statement { $$ = new iteration_statement($3, $4, $5, $7); }
 	;
 
 jump_statement
diff --git a/include/triton/ast/scanner.l b/include/triton/ast/scanner.l
index 56cc777a7..e3bf32be0 100644
--- a/include/triton/ast/scanner.l
+++ b/include/triton/ast/scanner.l
@@ -16,8 +16,8 @@ IS			(u|U|l|L)*
 "tunable"          { return(TUNABLE); }
 "kernel"           { return(KERNEL); }
 "restrict"         { return(RESTRICT); }
-"readonly"         { return(READONLY); }
-"writeonly"        { return(WRITEONLY); }
+"read_only"         { return(READONLY); }
+"write_only"        { return(WRITEONLY); }
 "@"                { return(AT); }
 "newaxis"		       { return(NEWAXIS); }
 "if"			         { return(IF); }
diff --git a/lib/ast/lowering.cpp b/lib/ast/lowering.cpp
index 49fe03206..db9c9ed2a 100644
--- a/lib/ast/lowering.cpp
+++ b/lib/ast/lowering.cpp
@@ -287,15 +287,8 @@ ir::value* function_definition::codegen(ir::module *mod) const{
 /* Statements */
 ir::value* compound_statement::codegen(ir::module* mod) const{
   mod->add_new_scope();
-  if(decls_)
-    decls_->codegen(mod);
-  if(statements_){
-    for(statement *stmt: statements_->values()){
-      ir::value *current = stmt->codegen(mod);
-      if(is_terminator(current))
-        return current;
-    }
-  }
+  if(items_)
+    items_->codegen(mod);
   mod->pop_scope();
   return nullptr;
 }
@@ -333,7 +326,8 @@ ir::value* iteration_statement::codegen(ir::module *mod) const{
   ir::basic_block *loop_bb = ir::basic_block::create(ctx, "loop", fn);
   ir::basic_block *next_bb = ir::basic_block::create(ctx, "postloop", fn);
   mod->set_continue_fn([&](){
-    exec_->codegen(mod);
+    if(exec_)
+      exec_->codegen(mod);
     ir::value *cond = stop_->codegen(mod);
     return builder.create_cond_br(cond, loop_bb, next_bb);
   });