Implement constant folding on ternary operations via fold_cond.

[xonotic/gmqcc.git] / fold.c

diff --git a/fold.c b/fold.c
index 74b9e4f77f436148b1be8c6ecfb7b77bb5d935bd..d51b7652dcc9b48efdd2bf42c0befe73d6c13503 100644 (file)
--- a/fold.c
+++ b/fold.c
@@ -163,6 +163,14 @@ static GMQCC_INLINE bool vec3_pbool(vec3_t a) {
     return (a.x && a.y && a.z);
 }
 
+static GMQCC_INLINE vec3_t vec3_cross(vec3_t a, vec3_t b) {
+    vec3_t out;
+    out.x = a.y * b.z - a.z * b.y;
+    out.y = a.z * b.x - a.x * b.z;
+    out.z = a.x * b.y - a.y * b.x;
+    return out;
+}
+
 static lex_ctx_t fold_ctx(fold_t *fold) {
     lex_ctx_t ctx;
     if (fold->parser->lex)
@@ -201,11 +209,25 @@ static GMQCC_INLINE bool fold_immediate_true(fold_t *fold, ast_value *v) {
                 ((ast_expression*)(X))->vtype != TYPE_FUNCTION)
 
 #define fold_can_2(X, Y) (fold_can_1(X) && fold_can_1(Y))
+#define fold_can_div(X) (fold_immvalue_float(X) != 0.0f)
 
 #define fold_immvalue_float(E)  ((E)->constval.vfloat)
 #define fold_immvalue_vector(E) ((E)->constval.vvec)
 #define fold_immvalue_string(E) ((E)->constval.vstring)
 
+#ifdef INFINITY
+#   define fold_infinity_float  INFINITY
+#else
+#   define fold_infinity_float  (1.0 / 0.0)
+#endif /*! INFINITY */
+
+#define fold_infinity_vector \
+    vec3_create(             \
+        fold_infinity_float, \
+        fold_infinity_float, \
+        fold_infinity_float  \
+    )
+
 fold_t *fold_init(parser_t *parser) {
     fold_t *fold                 = (fold_t*)mem_a(sizeof(fold_t));
     fold->parser                 = parser;
@@ -222,9 +244,11 @@ fold_t *fold_init(parser_t *parser) {
     (void)fold_constgen_float (fold,  0.0f);
     (void)fold_constgen_float (fold,  1.0f);
     (void)fold_constgen_float (fold, -1.0f);
+    (void)fold_constgen_float (fold,  fold_infinity_float); /* +inf */
 
     (void)fold_constgen_vector(fold, vec3_create(0.0f, 0.0f, 0.0f));
     (void)fold_constgen_vector(fold, vec3_create(-1.0f, -1.0f, -1.0f));
+    (void)fold_constgen_vector(fold, fold_infinity_vector); /* +inf */
 
     return fold;
 }
@@ -362,7 +386,7 @@ static GMQCC_INLINE ast_expression *fold_op_mul_vec(fold_t *fold, vec3_t vec, as
         out                        = (ast_expression*)ast_member_new(fold_ctx(fold), (ast_expression*)sel, set[0]-'x', NULL);
         out->node.keep             = false;
         ((ast_member*)out)->rvalue = true;
-        if (x != -1)
+        if (x != -1.0f)
             return (ast_expression*)ast_binary_new(fold_ctx(fold), INSTR_MUL_F, fold_constgen_float(fold, x), out);
     }
     return NULL;
@@ -454,12 +478,28 @@ static GMQCC_INLINE ast_expression *fold_op_mul(fold_t *fold, ast_value *a, ast_
 
 static GMQCC_INLINE ast_expression *fold_op_div(fold_t *fold, ast_value *a, ast_value *b) {
     if (isfloat(a)) {
-        if (fold_can_2(a, b))
-            return fold_constgen_float(fold, fold_immvalue_float(a) / fold_immvalue_float(b));
+        if (fold_can_2(a, b)) {
+            if (fold_can_div(b))
+                return fold_constgen_float(fold, fold_immvalue_float(a) / fold_immvalue_float(b));
+            else
+                return (ast_expression*)fold->imm_float[3]; /* inf */
+        } else if (fold_can_1(b)) {
+            return (ast_expression*)ast_binary_new(
+                fold_ctx(fold),
+                INSTR_MUL_F,
+                (ast_expression*)a,
+                fold_constgen_float(fold, 1.0f / fold_immvalue_float(b))
+            );
+        }
     } else if (isvector(a)) {
-        if (fold_can_2(a, b))
-            return fold_constgen_vector(fold, vec3_mulvf(fold_immvalue_vector(a), 1.0f / fold_immvalue_float(b)));
-        else {
+        if (fold_can_2(a, b)) {
+            if (fold_can_div(b)) {
+                return fold_constgen_vector(fold, vec3_mulvf(fold_immvalue_vector(a), 1.0f / fold_immvalue_float(b)));
+            }
+            else {
+                return (ast_expression*)fold->imm_vector[2]; /* inf */
+            }
+        } else {
             return (ast_expression*)ast_binary_new(
                 fold_ctx(fold),
                 INSTR_MUL_VF,
@@ -479,8 +519,12 @@ static GMQCC_INLINE ast_expression *fold_op_div(fold_t *fold, ast_value *a, ast_
 }
 
 static GMQCC_INLINE ast_expression *fold_op_mod(fold_t *fold, ast_value *a, ast_value *b) {
-    if (fold_can_2(a, b))
-        return fold_constgen_float(fold, (qcfloat_t)(((qcint_t)fold_immvalue_float(a)) % ((qcint_t)fold_immvalue_float(b))));
+    if (fold_can_2(a, b)) {
+        if (fold_can_div(b))
+            return fold_constgen_float(fold, (qcfloat_t)(((qcint_t)fold_immvalue_float(a)) % ((qcint_t)fold_immvalue_float(b))));
+        else
+            return (ast_expression*)fold->imm_float[3]; /* inf */
+    }
     return NULL;
 }
 
@@ -610,6 +654,12 @@ static GMQCC_INLINE ast_expression *fold_op_bnot(fold_t *fold, ast_value *a) {
     return NULL;
 }
 
+static GMQCC_INLINE ast_expression *fold_op_cross(fold_t *fold, ast_value *a, ast_value *b) {
+    if (fold_can_2(a, b))
+        return fold_constgen_vector(fold, vec3_cross(fold_immvalue_vector(a), fold_immvalue_vector(b)));
+    return NULL;
+}
+
 ast_expression *fold_op(fold_t *fold, const oper_info *info, ast_expression **opexprs) {
     ast_value      *a = (ast_value*)opexprs[0];
     ast_value      *b = (ast_value*)opexprs[1];
@@ -667,6 +717,7 @@ ast_expression *fold_op(fold_t *fold, const oper_info *info, ast_expression **op
         fold_op_case(2, ('!', '='),    cmp,    (fold, a, b, true));
         fold_op_case(2, ('=', '='),    cmp,    (fold, a, b, false));
         fold_op_case(2, ('~', 'P'),    bnot,   (fold, a));
+        fold_op_case(2, ('>', '<'),    cross,  (fold, a, b));
     }
     #undef fold_op_case
     compile_error(fold_ctx(fold), "internal error: attempted to constant-fold for unsupported operator");
@@ -746,7 +797,7 @@ ast_expression *fold_intrin(fold_t *fold, const char *intrin, ast_expression **a
 /*#define fold_can_2(X,Y)         (fold_can_1(X) && fold_can_1(Y))*/
 
 
-int fold_cond(ir_value *condval, ast_function *func, ast_ifthen *branch) {
+static GMQCC_INLINE int fold_cond(ir_value *condval, ast_function *func, ast_ifthen *branch) {
     if (isfloat(condval) && fold_can_1(condval) && OPTS_OPTIMIZATION(OPTIM_CONST_FOLD_DCE)) {
         ast_expression_codegen *cgen;
         ir_block               *elide;
@@ -780,3 +831,11 @@ int fold_cond(ir_value *condval, ast_function *func, ast_ifthen *branch) {
     }
     return -1; /* nothing done */
 }
+
+int fold_cond_ternary(ir_value *condval, ast_function *func, ast_ternary *branch) {
+    return fold_cond(condval, func, (ast_ifthen*)branch);
+}
+
+int fold_cond_ifthen(ir_value *condval, ast_function *func, ast_ifthen *branch) {
+    return fold_cond(condval, func, branch);
+}