vkd3d-shader/hlsl: Partially defer continue resolution.

We need 'for' iter blocks to be separate for loop unrolling.

libs/vkd3d-shader/hlsl.c

@@ -2064,7 +2064,7 @@ struct hlsl_ir_node *hlsl_new_jump(struct hlsl_ctx *ctx, enum hlsl_ir_jump_type
     return &jump->node;
 }
 
-struct hlsl_ir_node *hlsl_new_loop(struct hlsl_ctx *ctx,
+struct hlsl_ir_node *hlsl_new_loop(struct hlsl_ctx *ctx, struct hlsl_block *iter,
         struct hlsl_block *block, enum hlsl_ir_loop_unroll_type unroll_type,
         unsigned int unroll_limit, const struct vkd3d_shader_location *loc)
 {
@@ -2076,6 +2076,10 @@ struct hlsl_ir_node *hlsl_new_loop(struct hlsl_ctx *ctx,
     hlsl_block_init(&loop->body);
     hlsl_block_add_block(&loop->body, block);
 
+    hlsl_block_init(&loop->iter);
+    if (iter)
+        hlsl_block_add_block(&loop->iter, iter);
+
     loop->unroll_type = unroll_type;
     loop->unroll_limit = unroll_limit;
     return &loop->node;
@@ -2231,14 +2235,21 @@ static struct hlsl_ir_node *clone_load(struct hlsl_ctx *ctx, struct clone_instr_
 
 static struct hlsl_ir_node *clone_loop(struct hlsl_ctx *ctx, struct clone_instr_map *map, struct hlsl_ir_loop *src)
 {
+    struct hlsl_block iter, body;
     struct hlsl_ir_node *dst;
-    struct hlsl_block body;
 
-    if (!clone_block(ctx, &body, &src->body, map))
+    if (!clone_block(ctx, &iter, &src->iter, map))
         return NULL;
 
-    if (!(dst = hlsl_new_loop(ctx, &body, src->unroll_type, src->unroll_limit, &src->node.loc)))
+    if (!clone_block(ctx, &body, &src->body, map))
     {
+        hlsl_block_cleanup(&iter);
+        return NULL;
+    }
+
+    if (!(dst = hlsl_new_loop(ctx, &iter, &body, src->unroll_type, src->unroll_limit, &src->node.loc)))
+    {
+        hlsl_block_cleanup(&iter);
         hlsl_block_cleanup(&body);
         return NULL;
     }
@@ -3713,6 +3724,7 @@ static void free_ir_load(struct hlsl_ir_load *load)
 static void free_ir_loop(struct hlsl_ir_loop *loop)
 {
     hlsl_block_cleanup(&loop->body);
+    hlsl_block_cleanup(&loop->iter);
     vkd3d_free(loop);
 }
 

libs/vkd3d-shader/hlsl.h

@@ -666,11 +666,20 @@ enum hlsl_ir_loop_unroll_type
     HLSL_IR_LOOP_FORCE_LOOP
 };
 
+enum hlsl_loop_type
+{
+    HLSL_LOOP_FOR,
+    HLSL_LOOP_WHILE,
+    HLSL_LOOP_DO_WHILE
+};
+
 struct hlsl_ir_loop
 {
     struct hlsl_ir_node node;
+    struct hlsl_block iter;
     /* loop condition is stored in the body (as "if (!condition) break;") */
     struct hlsl_block body;
+    enum hlsl_loop_type type;
     unsigned int next_index; /* liveness index of the end of the loop */
     unsigned int unroll_limit;
     enum hlsl_ir_loop_unroll_type unroll_type;
@@ -1550,8 +1559,9 @@ struct hlsl_ir_node *hlsl_new_compile(struct hlsl_ctx *ctx, enum hlsl_compile_ty
         struct hlsl_block *args_instrs, const struct vkd3d_shader_location *loc);
 struct hlsl_ir_node *hlsl_new_index(struct hlsl_ctx *ctx, struct hlsl_ir_node *val,
         struct hlsl_ir_node *idx, const struct vkd3d_shader_location *loc);
-struct hlsl_ir_node *hlsl_new_loop(struct hlsl_ctx *ctx,
-        struct hlsl_block *block, enum hlsl_ir_loop_unroll_type unroll_type, unsigned int unroll_limit, const struct vkd3d_shader_location *loc);
+struct hlsl_ir_node *hlsl_new_loop(struct hlsl_ctx *ctx, struct hlsl_block *iter,
+        struct hlsl_block *block, enum hlsl_ir_loop_unroll_type unroll_type,
+        unsigned int unroll_limit, const struct vkd3d_shader_location *loc);
 struct hlsl_ir_node *hlsl_new_resource_load(struct hlsl_ctx *ctx,
         const struct hlsl_resource_load_params *params, const struct vkd3d_shader_location *loc);
 struct hlsl_ir_node *hlsl_new_resource_store(struct hlsl_ctx *ctx, const struct hlsl_deref *resource,

libs/vkd3d-shader/hlsl.y

@@ -555,13 +555,6 @@ static bool append_conditional_break(struct hlsl_ctx *ctx, struct hlsl_block *co
     return true;
 }
 
-enum loop_type
-{
-    LOOP_FOR,
-    LOOP_WHILE,
-    LOOP_DO_WHILE
-};
-
 static void check_attribute_list_for_duplicates(struct hlsl_ctx *ctx, const struct parse_attribute_list *attrs)
 {
     unsigned int i, j;
@@ -577,8 +570,8 @@ static void check_attribute_list_for_duplicates(struct hlsl_ctx *ctx, const stru
     }
 }
 
-static void resolve_loop_continue(struct hlsl_ctx *ctx, struct hlsl_block *block, enum loop_type type,
-        struct hlsl_block *cond, struct hlsl_block *iter)
+static void resolve_loop_continue(struct hlsl_ctx *ctx, struct hlsl_block *block,
+        enum hlsl_loop_type type, struct hlsl_block *cond)
 {
     struct hlsl_ir_node *instr, *next;
 
@@ -588,8 +581,8 @@ static void resolve_loop_continue(struct hlsl_ctx *ctx, struct hlsl_block *block
         {
             struct hlsl_ir_if *iff = hlsl_ir_if(instr);
 
-            resolve_loop_continue(ctx, &iff->then_block, type, cond, iter);
-            resolve_loop_continue(ctx, &iff->else_block, type, cond, iter);
+            resolve_loop_continue(ctx, &iff->then_block, type, cond);
+            resolve_loop_continue(ctx, &iff->else_block, type, cond);
         }
         else if (instr->type == HLSL_IR_JUMP)
         {
@@ -599,7 +592,7 @@ static void resolve_loop_continue(struct hlsl_ctx *ctx, struct hlsl_block *block
             if (jump->type != HLSL_IR_JUMP_UNRESOLVED_CONTINUE)
                 continue;
 
-            if (type == LOOP_DO_WHILE)
+            if (type == HLSL_LOOP_DO_WHILE)
             {
                 if (!hlsl_clone_block(ctx, &cond_block, cond))
                     return;
@@ -610,13 +603,6 @@ static void resolve_loop_continue(struct hlsl_ctx *ctx, struct hlsl_block *block
                 }
                 list_move_before(&instr->entry, &cond_block.instrs);
             }
-            else if (type == LOOP_FOR)
-            {
-                if (!hlsl_clone_block(ctx, &cond_block, iter))
-                    return;
-                list_move_before(&instr->entry, &cond_block.instrs);
-            }
-            jump->type = HLSL_IR_JUMP_CONTINUE;
         }
     }
 }
@@ -740,7 +726,7 @@ static unsigned int evaluate_static_expression_as_uint(struct hlsl_ctx *ctx, str
     return res.number.u;
 }
 
-static struct hlsl_block *create_loop(struct hlsl_ctx *ctx, enum loop_type type,
+static struct hlsl_block *create_loop(struct hlsl_ctx *ctx, enum hlsl_loop_type type,
         const struct parse_attribute_list *attributes, struct hlsl_block *init, struct hlsl_block *cond,
         struct hlsl_block *iter, struct hlsl_block *body, const struct vkd3d_shader_location *loc)
 {
@@ -792,7 +778,7 @@ static struct hlsl_block *create_loop(struct hlsl_ctx *ctx, enum loop_type type,
         }
     }
 
-    resolve_loop_continue(ctx, body, type, cond, iter);
+    resolve_loop_continue(ctx, body, type, cond);
 
     if (!init && !(init = make_empty_block(ctx)))
         goto oom;
@@ -800,15 +786,12 @@ static struct hlsl_block *create_loop(struct hlsl_ctx *ctx, enum loop_type type,
     if (!append_conditional_break(ctx, cond))
         goto oom;
 
-    if (iter)
-        hlsl_block_add_block(body, iter);
-
-    if (type == LOOP_DO_WHILE)
+    if (type == HLSL_LOOP_DO_WHILE)
         list_move_tail(&body->instrs, &cond->instrs);
     else
         list_move_head(&body->instrs, &cond->instrs);
 
-    if (!(loop = hlsl_new_loop(ctx, body, unroll_type, unroll_limit, loc)))
+    if (!(loop = hlsl_new_loop(ctx, iter, body, unroll_type, unroll_limit, loc)))
         goto oom;
     hlsl_block_add_instr(init, loop);
 
@@ -8831,25 +8814,25 @@ if_body:
 loop_statement:
       attribute_list_optional loop_scope_start KW_WHILE '(' expr ')' statement
         {
-            $$ = create_loop(ctx, LOOP_WHILE, &$1, NULL, $5, NULL, $7, &@3);
+            $$ = create_loop(ctx, HLSL_LOOP_WHILE, &$1, NULL, $5, NULL, $7, &@3);
             hlsl_pop_scope(ctx);
             cleanup_parse_attribute_list(&$1);
         }
     | attribute_list_optional loop_scope_start KW_DO statement KW_WHILE '(' expr ')' ';'
         {
-            $$ = create_loop(ctx, LOOP_DO_WHILE, &$1, NULL, $7, NULL, $4, &@3);
+            $$ = create_loop(ctx, HLSL_LOOP_DO_WHILE, &$1, NULL, $7, NULL, $4, &@3);
             hlsl_pop_scope(ctx);
             cleanup_parse_attribute_list(&$1);
         }
     | attribute_list_optional loop_scope_start KW_FOR '(' expr_statement expr_statement expr_optional ')' statement
         {
-            $$ = create_loop(ctx, LOOP_FOR, &$1, $5, $6, $7, $9, &@3);
+            $$ = create_loop(ctx, HLSL_LOOP_FOR, &$1, $5, $6, $7, $9, &@3);
             hlsl_pop_scope(ctx);
             cleanup_parse_attribute_list(&$1);
         }
     | attribute_list_optional loop_scope_start KW_FOR '(' declaration expr_statement expr_optional ')' statement
         {
-            $$ = create_loop(ctx, LOOP_FOR, &$1, $5, $6, $7, $9, &@3);
+            $$ = create_loop(ctx, HLSL_LOOP_FOR, &$1, $5, $6, $7, $9, &@3);
             hlsl_pop_scope(ctx);
             cleanup_parse_attribute_list(&$1);
         }

libs/vkd3d-shader/hlsl_codegen.c

@@ -1954,6 +1954,7 @@ static bool copy_propagation_process_loop(struct hlsl_ctx *ctx, struct hlsl_ir_l
     bool progress = false;
 
     copy_propagation_invalidate_from_block(ctx, state, &loop->body, loop->node.index);
+    copy_propagation_invalidate_from_block(ctx, state, &loop->iter, loop->node.index);
 
     copy_propagation_push_scope(state, ctx);
     progress |= copy_propagation_transform_block(ctx, &loop->body, state);
@@ -10177,6 +10178,101 @@ static bool unroll_loops(struct hlsl_ctx *ctx, struct hlsl_ir_node *node, void *
     return true;
 }
 
+/* We could handle this at parse time. However, loop unrolling often needs to
+ * know the value of variables modified in the "iter" block. It is possible to
+ * detect that all exit paths of a loop body modify such variables in the same
+ * way, but difficult, and d3dcompiler does not attempt to do so.
+ * In fact, d3dcompiler is capable of unrolling the following loop:
+ * for (int i = 0; i < 10; ++i)
+ * {
+ *     if (some_uniform > 4)
+ *         continue;
+ * }
+ * but cannot unroll the same loop with "++i" moved to each exit path:
+ * for (int i = 0; i < 10;)
+ * {
+ *     if (some_uniform > 4)
+ *     {
+ *         ++i;
+ *         continue;
+ *     }
+ *     ++i;
+ * }
+ */
+static bool resolve_loops(struct hlsl_ctx *ctx, struct hlsl_ir_node *node, void *context)
+{
+    struct hlsl_ir_loop *loop;
+
+    if (node->type != HLSL_IR_LOOP)
+        return true;
+
+    loop = hlsl_ir_loop(node);
+
+    hlsl_block_add_block(&loop->body, &loop->iter);
+    return true;
+}
+
+static void resolve_continues(struct hlsl_ctx *ctx, struct hlsl_block *block, struct hlsl_ir_loop *last_loop)
+{
+    struct hlsl_ir_node *node;
+
+    LIST_FOR_EACH_ENTRY(node, &block->instrs, struct hlsl_ir_node, entry)
+    {
+        switch (node->type)
+        {
+            case HLSL_IR_LOOP:
+            {
+                struct hlsl_ir_loop *loop = hlsl_ir_loop(node);
+
+                resolve_continues(ctx, &loop->body, loop);
+                break;
+            }
+            case HLSL_IR_IF:
+            {
+                struct hlsl_ir_if *iff = hlsl_ir_if(node);
+                resolve_continues(ctx, &iff->then_block, last_loop);
+                resolve_continues(ctx, &iff->else_block, last_loop);
+                break;
+            }
+            case HLSL_IR_SWITCH:
+            {
+                struct hlsl_ir_switch *s = hlsl_ir_switch(node);
+                struct hlsl_ir_switch_case *c;
+
+                LIST_FOR_EACH_ENTRY(c, &s->cases, struct hlsl_ir_switch_case, entry)
+                {
+                    resolve_continues(ctx, &c->body, last_loop);
+                }
+
+                break;
+            }
+            case HLSL_IR_JUMP:
+            {
+                struct hlsl_ir_jump *jump = hlsl_ir_jump(node);
+
+                if (jump->type != HLSL_IR_JUMP_UNRESOLVED_CONTINUE)
+                    break;
+
+                if (last_loop->type == HLSL_LOOP_FOR)
+                {
+                    struct hlsl_block draft;
+
+                    if (!hlsl_clone_block(ctx, &draft, &last_loop->iter))
+                        return;
+
+                    list_move_before(&node->entry, &draft.instrs);
+                    hlsl_block_cleanup(&draft);
+                }
+
+                jump->type = HLSL_IR_JUMP_CONTINUE;
+                break;
+            }
+            default:
+                break;
+        }
+    }
+}
+
 static void loop_unrolling_execute(struct hlsl_ctx *ctx, struct hlsl_block *block)
 {
     bool progress;
@@ -10190,6 +10286,8 @@ static void loop_unrolling_execute(struct hlsl_ctx *ctx, struct hlsl_block *bloc
     } while (progress);
     hlsl_transform_ir(ctx, split_matrix_copies, block, NULL);
 
+    resolve_continues(ctx, block, NULL);
+    hlsl_transform_ir(ctx, resolve_loops, block, NULL);
     hlsl_transform_ir(ctx, unroll_loops, block, block);
 }