[PATCH vkd3d 2/5] vkd3d-shader: Lower preincrement and predecrement to assignment operations at parse time.

[Zebediah Figura]

Signed-off-by: Zebediah Figura 
---
 libs/vkd3d-shader/hlsl.c |  2 --
 libs/vkd3d-shader/hlsl.h |  2 --
 libs/vkd3d-shader/hlsl.y | 28 ++++++++++++++++++++++------
 3 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/libs/vkd3d-shader/hlsl.c b/libs/vkd3d-shader/hlsl.c
index e78f05c3..2312b9d3 100644
--- a/libs/vkd3d-shader/hlsl.c
+++ b/libs/vkd3d-shader/hlsl.c
@@ -983,8 +983,6 @@ static const char *debug_expr_op(const struct hlsl_ir_expr *expr)

"sat",

-        "pre++",
-        "pre--",
         "post++",
         "post--",

diff --git a/libs/vkd3d-shader/hlsl.h b/libs/vkd3d-shader/hlsl.h
index 76734401..b64ce2d5 100644
--- a/libs/vkd3d-shader/hlsl.h
+++ b/libs/vkd3d-shader/hlsl.h
@@ -276,8 +276,6 @@ enum hlsl_ir_expr_op

HLSL_IR_UNOP_SAT,

-    HLSL_IR_UNOP_PREINC,
-    HLSL_IR_UNOP_PREDEC,
     HLSL_IR_UNOP_POSTINC,
     HLSL_IR_UNOP_POSTDEC,

diff --git a/libs/vkd3d-shader/hlsl.y b/libs/vkd3d-shader/hlsl.y
index a9c9dd02..95a2ed69 100644
--- a/libs/vkd3d-shader/hlsl.y
+++ b/libs/vkd3d-shader/hlsl.y
@@ -1348,6 +1348,22 @@ static struct hlsl_ir_node *add_assignment(struct hlsl_ctx *ctx, struct list *in
     return &copy->node;
 }

+static bool add_increment(struct hlsl_ctx *ctx, struct list *instrs, bool decrement, struct vkd3d_shader_location loc)
+{
+    struct hlsl_ir_node *lhs = node_from_list(instrs);
+    struct hlsl_ir_constant *one;
+
+    if (lhs->data_type->modifiers & HLSL_MODIFIER_CONST)
+        hlsl_error(ctx, loc, VKD3D_SHADER_ERROR_HLSL_MODIFIES_CONST,
+                "Argument to pre%screment operator is const.", decrement ? "de" : "in");
+
+    if (!(one = hlsl_new_uint_constant(ctx, 1, loc)))
+        return false;
+    list_add_tail(instrs, &one->node.entry);
+
+    return !!add_assignment(ctx, instrs, lhs, decrement ? ASSIGN_OP_SUB : ASSIGN_OP_ADD, &one->node);
+}
+
 static void struct_var_initializer(struct hlsl_ctx *ctx, struct list *list, struct hlsl_ir_var *var,
         struct parse_initializer *initializer)
 {
@@ -2785,21 +2801,21 @@ unary_expr:
       postfix_expr
     | OP_INC unary_expr
         {
-            if (node_from_list($2)->data_type->modifiers & HLSL_MODIFIER_CONST)
+            if (!add_increment(ctx, $2, false, @1))
             {
-                hlsl_error(ctx, @1, VKD3D_SHADER_ERROR_HLSL_MODIFIES_CONST, "Statement modifies a const expression.");
+                hlsl_free_instr_list($2);
                 YYABORT;
             }
-            $$ = append_unop($2, hlsl_new_unary_expr(HLSL_IR_UNOP_PREINC, node_from_list($2), @1));
+            $$ = $2;
         }
     | OP_DEC unary_expr
         {
-            if (node_from_list($2)->data_type->modifiers & HLSL_MODIFIER_CONST)
+            if (!add_increment(ctx, $2, true, @1))
             {
-                hlsl_error(ctx, @1, VKD3D_SHADER_ERROR_HLSL_MODIFIES_CONST, "Statement modifies a const expression.");
+                hlsl_free_instr_list($2);
                 YYABORT;
             }
-            $$ = append_unop($2, hlsl_new_unary_expr(HLSL_IR_UNOP_PREDEC, node_from_list($2), @1));
+            $$ = $2;
         }
     | unary_op unary_expr
         {