fold_binary now used instead of ast_binary_new, which calls fold_superfluous
[xonotic/gmqcc.git] / fold.c
diff --git a/fold.c b/fold.c
index c7abaeb..c9f1a06 100644 (file)
--- a/fold.c
+++ b/fold.c
  * stage constant folding, where, witht he help of the AST, operator
  * usages can be constant folded. Then there is the constant folding
  * in the IR for things like eliding if statements, can occur.
- * 
+ *
  * This file is thus, split into two parts.
  */
-ast_expression **fold_const_values = NULL;
-
-static GMQCC_INLINE bool fold_possible(const ast_value *val) {
-    return  ast_istype((ast_expression*)val, ast_value) &&
-            val->hasvalue && (val->cvq == CV_CONST)     &&
-            ((ast_expression*)val)->vtype != TYPE_FUNCTION; /* why not for functions? */
-}
 
-#define isfloatonly(X)  (((ast_expression*)(X))->vtype == TYPE_FLOAT)
-#define isvectoronly(X) (((ast_expression*)(X))->vtype == TYPE_VECTOR)
-#define isstringonly(X) (((ast_expression*)(X))->vtype == TYPE_STRING)
-#define isfloat(X)      (isfloatonly (X) && fold_possible(X))
-#define isvector(X)     (isvectoronly(X) && fold_possible(X))
-#define isstring(X)     (isstringonly(X) && fold_possible(X))
-#define isfloats(X,Y)   (isfloat     (X) && isfloat (Y))
-#define isvectors(X,Y)  (isvector    (X) && isvector(Y))
-#define isstrings(X,Y)  (isstring    (X) && isstring(Y))
+#define isfloat(X)      (((ast_expression*)(X))->vtype == TYPE_FLOAT)
+#define isvector(X)     (((ast_expression*)(X))->vtype == TYPE_VECTOR)
+#define isstring(X)     (((ast_expression*)(X))->vtype == TYPE_STRING)
+#define isfloats(X,Y)   (isfloat  (X) && isfloat (Y))
 
 /*
  * Implementation of basic vector math for vec3_t, for trivial constant
  * folding.
- * 
+ *
  * TODO: gcc/clang hinting for autovectorization
  */
 static GMQCC_INLINE vec3_t vec3_add(vec3_t a, vec3_t b) {
@@ -77,14 +65,6 @@ static GMQCC_INLINE vec3_t vec3_sub(vec3_t a, vec3_t b) {
     return out;
 }
 
-static GMQCC_INLINE vec3_t vec3_not(vec3_t a) {
-    vec3_t out;
-    out.x = !a.x;
-    out.y = !a.y;
-    out.z = !a.z;
-    return out;
-}
-
 static GMQCC_INLINE vec3_t vec3_neg(vec3_t a) {
     vec3_t out;
     out.x = -a.x;
@@ -93,19 +73,59 @@ static GMQCC_INLINE vec3_t vec3_neg(vec3_t a) {
     return out;
 }
 
+static GMQCC_INLINE vec3_t vec3_or(vec3_t a, vec3_t b) {
+    vec3_t out;
+    out.x = (qcfloat_t)(((qcint_t)a.x) | ((qcint_t)b.x));
+    out.y = (qcfloat_t)(((qcint_t)a.y) | ((qcint_t)b.y));
+    out.z = (qcfloat_t)(((qcint_t)a.z) | ((qcint_t)b.z));
+    return out;
+}
+
+static GMQCC_INLINE vec3_t vec3_orvf(vec3_t a, qcfloat_t b) {
+    vec3_t out;
+    out.x = (qcfloat_t)(((qcint_t)a.x) | ((qcint_t)b));
+    out.y = (qcfloat_t)(((qcint_t)a.y) | ((qcint_t)b));
+    out.z = (qcfloat_t)(((qcint_t)a.z) | ((qcint_t)b));
+    return out;
+}
+
+static GMQCC_INLINE vec3_t vec3_and(vec3_t a, vec3_t b) {
+    vec3_t out;
+    out.x = (qcfloat_t)(((qcint_t)a.x) & ((qcint_t)b.x));
+    out.y = (qcfloat_t)(((qcint_t)a.y) & ((qcint_t)b.y));
+    out.z = (qcfloat_t)(((qcint_t)a.z) & ((qcint_t)b.z));
+    return out;
+}
+
+static GMQCC_INLINE vec3_t vec3_andvf(vec3_t a, qcfloat_t b) {
+    vec3_t out;
+    out.x = (qcfloat_t)(((qcint_t)a.x) & ((qcint_t)b));
+    out.y = (qcfloat_t)(((qcint_t)a.y) & ((qcint_t)b));
+    out.z = (qcfloat_t)(((qcint_t)a.z) & ((qcint_t)b));
+    return out;
+}
+
 static GMQCC_INLINE vec3_t vec3_xor(vec3_t a, vec3_t b) {
     vec3_t out;
-    out.x = (qcfloat_t)((qcint_t)a.x ^ (qcint_t)b.x);
-    out.y = (qcfloat_t)((qcint_t)a.y ^ (qcint_t)b.y);
-    out.z = (qcfloat_t)((qcint_t)a.z ^ (qcint_t)b.z);
+    out.x = (qcfloat_t)(((qcint_t)a.x) ^ ((qcint_t)b.x));
+    out.y = (qcfloat_t)(((qcint_t)a.y) ^ ((qcint_t)b.y));
+    out.z = (qcfloat_t)(((qcint_t)a.z) ^ ((qcint_t)b.z));
     return out;
 }
 
 static GMQCC_INLINE vec3_t vec3_xorvf(vec3_t a, qcfloat_t b) {
     vec3_t out;
-    out.x = (qcfloat_t)((qcint_t)a.x ^ (qcint_t)b);
-    out.y = (qcfloat_t)((qcint_t)a.y ^ (qcint_t)b);
-    out.z = (qcfloat_t)((qcint_t)a.z ^ (qcint_t)b);
+    out.x = (qcfloat_t)(((qcint_t)a.x) ^ ((qcint_t)b));
+    out.y = (qcfloat_t)(((qcint_t)a.y) ^ ((qcint_t)b));
+    out.z = (qcfloat_t)(((qcint_t)a.z) ^ ((qcint_t)b));
+    return out;
+}
+
+static GMQCC_INLINE vec3_t vec3_not(vec3_t a) {
+    vec3_t out;
+    out.x = (qcfloat_t)(~((qcint_t)a.x));
+    out.y = (qcfloat_t)(~((qcint_t)a.y));
+    out.z = (qcfloat_t)(~((qcint_t)a.z));
     return out;
 }
 
@@ -113,7 +133,6 @@ static GMQCC_INLINE qcfloat_t vec3_mulvv(vec3_t a, vec3_t b) {
     return (a.x * b.x + a.y * b.y + a.z * b.z);
 }
 
-
 static GMQCC_INLINE vec3_t vec3_mulvf(vec3_t a, qcfloat_t b) {
     vec3_t out;
     out.x = a.x * b;
@@ -136,17 +155,64 @@ static GMQCC_INLINE vec3_t vec3_create(float x, float y, float z) {
     return out;
 }
 
+static GMQCC_INLINE qcfloat_t vec3_notf(vec3_t a) {
+    return (!a.x && !a.y && !a.z);
+}
+
+static GMQCC_INLINE bool vec3_pbool(vec3_t a) {
+    return (a.x && a.y && a.z);
+}
 
-static GMQCC_INLINE float fold_immvalue_float(ast_value *expr) {
-    return expr->constval.vfloat;
+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 GMQCC_INLINE vec3_t fold_immvalue_vector(ast_value *expr) {
-    return expr->constval.vvec;
+
+static lex_ctx_t fold_ctx(fold_t *fold) {
+    lex_ctx_t ctx;
+    if (fold->parser->lex)
+        return parser_ctx(fold->parser);
+
+    memset(&ctx, 0, sizeof(ctx));
+    return ctx;
 }
-static GMQCC_INLINE const char *fold_immvalue_string(ast_value *expr) {
-    return expr->constval.vstring;
+
+static GMQCC_INLINE bool fold_immediate_true(fold_t *fold, ast_value *v) {
+    switch (v->expression.vtype) {
+        case TYPE_FLOAT:
+            return !!v->constval.vfloat;
+        case TYPE_INTEGER:
+            return !!v->constval.vint;
+        case TYPE_VECTOR:
+            if (OPTS_FLAG(CORRECT_LOGIC))
+                return vec3_pbool(v->constval.vvec);
+            return !!(v->constval.vvec.x);
+        case TYPE_STRING:
+            if (!v->constval.vstring)
+                return false;
+            if (OPTS_FLAG(TRUE_EMPTY_STRINGS))
+                return true;
+            return !!v->constval.vstring[0];
+        default:
+            compile_error(fold_ctx(fold), "internal error: fold_immediate_true on invalid type");
+            break;
+    }
+    return !!v->constval.vfunc;
 }
 
+/* Handy macros to determine if an ast_value can be constant folded. */
+#define fold_can_1(X)  \
+    (ast_istype(((ast_expression*)(X)), ast_value) && (X)->hasvalue && ((X)->cvq == CV_CONST) && \
+                ((ast_expression*)(X))->vtype != TYPE_FUNCTION)
+
+#define fold_can_2(X, Y) (fold_can_1(X) && fold_can_1(Y))
+
+#define fold_immvalue_float(E)  ((E)->constval.vfloat)
+#define fold_immvalue_vector(E) ((E)->constval.vvec)
+#define fold_immvalue_string(E) ((E)->constval.vstring)
 
 fold_t *fold_init(parser_t *parser) {
     fold_t *fold                 = (fold_t*)mem_a(sizeof(fold_t));
@@ -166,6 +232,7 @@ fold_t *fold_init(parser_t *parser) {
     (void)fold_constgen_float (fold, -1.0f);
 
     (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));
 
     return fold;
 }
@@ -207,21 +274,12 @@ void fold_cleanup(fold_t *fold) {
     mem_d(fold);
 }
 
-static lex_ctx_t fold_ctx(fold_t *fold) {
-    lex_ctx_t ctx;
-    if (fold->parser->lex)
-        return parser_ctx(fold->parser);
-
-    memset(&ctx, 0, sizeof(ctx));
-    return ctx;
-}
-
 ast_expression *fold_constgen_float(fold_t *fold, qcfloat_t value) {
     ast_value  *out = NULL;
     size_t      i;
 
     for (i = 0; i < vec_size(fold->imm_float); i++) {
-        if (fold->imm_float[i]->constval.vfloat == value)
+        if (!memcmp(&fold->imm_float[i]->constval.vfloat, &value, sizeof(qcfloat_t)))
             return (ast_expression*)fold->imm_float[i];
     }
 
@@ -281,29 +339,30 @@ ast_expression *fold_constgen_string(fold_t *fold, const char *str, bool transla
     return (ast_expression*)out;
 }
 
-static GMQCC_INLINE ast_expression *fold_op_mul_vec(fold_t *fold, vec3_t *vec, ast_value *sel, const char *set) {
+
+static GMQCC_INLINE ast_expression *fold_op_mul_vec(fold_t *fold, vec3_t vec, ast_value *sel, const char *set) {
     /*
      * vector-component constant folding works by matching the component sets
      * to eliminate expensive operations on whole-vectors (3 components at runtime).
-     * to achive this effect in a clean manner this function generalizes the 
+     * to achive this effect in a clean manner this function generalizes the
      * values through the use of a set paramater, which is used as an indexing method
      * for creating the elided ast binary expression.
      *
      * Consider 'n 0 0' where y, and z need to be tested for 0, and x is
-     * used as the value in a binary operation generating an INSTR_MUL instruction
+     * used as the value in a binary operation generating an INSTR_MUL instruction,
      * to acomplish the indexing of the correct component value we use set[0], set[1], set[2]
      * as x, y, z, where the values of those operations return 'x', 'y', 'z'. Because
      * of how ASCII works we can easily deliniate:
      * vec.z is the same as set[2]-'x' for when set[2] is 'z', 'z'-'x' results in a
      * literal value of 2, using this 2, we know that taking the address of vec->x (float)
      * and indxing it with this literal will yeild the immediate address of that component
-     * 
+     *
      * Of course more work needs to be done to generate the correct index for the ast_member_new
      * call, which is no problem: set[0]-'x' suffices that job.
      */
-    qcfloat_t x = (&vec->x)[set[0]-'x'];
-    qcfloat_t y = (&vec->x)[set[1]-'x'];
-    qcfloat_t z = (&vec->x)[set[2]-'x'];
+    qcfloat_t x = (&vec.x)[set[0]-'x'];
+    qcfloat_t y = (&vec.x)[set[1]-'x'];
+    qcfloat_t z = (&vec.x)[set[2]-'x'];
 
     if (!y && !z) {
         ast_expression *out;
@@ -311,56 +370,273 @@ static GMQCC_INLINE ast_expression *fold_op_mul_vec(fold_t *fold, vec3_t *vec, a
         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;
+}
+
 
+static GMQCC_INLINE ast_expression *fold_op_neg(fold_t *fold, ast_value *a) {
+    if (isfloat(a)) {
+        if (fold_can_1(a))
+            return fold_constgen_float(fold, -fold_immvalue_float(a));
+    } else if (isvector(a)) {
+        if (fold_can_1(a))
+            return fold_constgen_vector(fold, vec3_neg(fold_immvalue_vector(a)));
+    }
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_not(fold_t *fold, ast_value *a) {
+    if (isfloat(a)) {
+        if (fold_can_1(a))
+            return fold_constgen_float(fold, !fold_immvalue_float(a));
+    } else if (isvector(a)) {
+        if (fold_can_1(a))
+            return fold_constgen_float(fold, vec3_notf(fold_immvalue_vector(a)));
+    } else if (isstring(a)) {
+        if (fold_can_1(a)) {
+            if (OPTS_FLAG(TRUE_EMPTY_STRINGS))
+                return fold_constgen_float(fold, !fold_immvalue_string(a));
+            else
+                return fold_constgen_float(fold, !fold_immvalue_string(a) || !*fold_immvalue_string(a));
+        }
+    }
     return NULL;
 }
 
+static GMQCC_INLINE ast_expression *fold_op_add(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));
+    } else if (isvector(a)) {
+        if (fold_can_2(a, b))
+            return fold_constgen_vector(fold, vec3_add(fold_immvalue_vector(a), fold_immvalue_vector(b)));
+    }
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_sub(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));
+    } else if (isvector(a)) {
+        if (fold_can_2(a, b))
+            return fold_constgen_vector(fold, vec3_sub(fold_immvalue_vector(a), fold_immvalue_vector(b)));
+    }
+    return NULL;
+}
 
 static GMQCC_INLINE ast_expression *fold_op_mul(fold_t *fold, ast_value *a, ast_value *b) {
-    if (isfloatonly(a)) {
-        return (fold_possible(a) && fold_possible(b))
-                    ? fold_constgen_vector(fold, vec3_mulvf(fold_immvalue_vector(b), fold_immvalue_float(a))) /* a=float,  b=vector */
-                    : NULL;                                                                                   /* cannot fold them   */
-    } else if (isfloats(a, b)) {
-        return fold_constgen_float(fold, fold_immvalue_float(a) * fold_immvalue_float(b));                    /* a=float,  b=float  */
-    } else if (isvectoronly(a)) {
-        if (isfloat(b) && fold_possible(a))
-            return fold_constgen_vector(fold, vec3_mulvf(fold_immvalue_vector(a), fold_immvalue_float(b)));   /* a=vector, b=float  */
-        else if (isvector(b)) {
-            /*
-             * if we made it here the two ast values are both vectors. However because vectors are represented as
-             * three float values, constant folding can still occur within reason of the individual const-qualification
-             * of the components the vector is composed of.
-             */
-            if (fold_possible(a) && fold_possible(b))
+    if (isfloat(a)) {
+        if (isvector(b)) {
+            if (fold_can_2(a, b))
+                return fold_constgen_vector(fold, vec3_mulvf(fold_immvalue_vector(b), fold_immvalue_float(a)));
+        } else {
+            if (fold_can_2(a, b))
+                return fold_constgen_float(fold, fold_immvalue_float(a) * fold_immvalue_float(b));
+        }
+    } else if (isvector(a)) {
+        if (isfloat(b)) {
+            if (fold_can_2(a, b))
+                return fold_constgen_vector(fold, vec3_mulvf(fold_immvalue_vector(a), fold_immvalue_float(b)));
+        } else {
+            if (fold_can_2(a, b)) {
                 return fold_constgen_float(fold, vec3_mulvv(fold_immvalue_vector(a), fold_immvalue_vector(b)));
-            else if (OPTS_OPTIMIZATION(OPTIM_VECTOR_COMPONENTS) && fold_possible(a)) {
-                vec3_t          vec = fold_immvalue_vector(a);
+            } else if (OPTS_OPTIMIZATION(OPTIM_VECTOR_COMPONENTS) && fold_can_1(a)) {
                 ast_expression *out;
-                if ((out = fold_op_mul_vec(fold, &vec, b, "xyz"))) return out;
-                if ((out = fold_op_mul_vec(fold, &vec, b, "yxz"))) return out;
-                if ((out = fold_op_mul_vec(fold, &vec, b, "zxy"))) return out;
-                return NULL;
-            } else if (OPTS_OPTIMIZATION(OPTIM_VECTOR_COMPONENTS) && fold_possible(b)) {
-                vec3_t          vec = fold_immvalue_vector(b);
+                if ((out = fold_op_mul_vec(fold, fold_immvalue_vector(a), b, "xyz"))) return out;
+                if ((out = fold_op_mul_vec(fold, fold_immvalue_vector(a), b, "yxz"))) return out;
+                if ((out = fold_op_mul_vec(fold, fold_immvalue_vector(a), b, "zxy"))) return out;
+            } else if (OPTS_OPTIMIZATION(OPTIM_VECTOR_COMPONENTS) && fold_can_1(b)) {
                 ast_expression *out;
-                if ((out = fold_op_mul_vec(fold, &vec, a, "xyz"))) return out;
-                if ((out = fold_op_mul_vec(fold, &vec, a, "yxz"))) return out;
-                if ((out = fold_op_mul_vec(fold, &vec, a, "zxy"))) return out;
-                return NULL;
+                if ((out = fold_op_mul_vec(fold, fold_immvalue_vector(b), a, "xyz"))) return out;
+                if ((out = fold_op_mul_vec(fold, fold_immvalue_vector(b), a, "yxz"))) return out;
+                if ((out = fold_op_mul_vec(fold, fold_immvalue_vector(b), a, "zxy"))) return out;
             }
         }
     }
     return NULL;
 }
 
+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));
+        } 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 {
+            return (ast_expression*)ast_binary_new(
+                fold_ctx(fold),
+                INSTR_MUL_VF,
+                (ast_expression*)a,
+                (fold_can_1(b))
+                    ? (ast_expression*)fold_constgen_float(fold, 1.0f / fold_immvalue_float(b))
+                    : (ast_expression*)ast_binary_new(
+                                            fold_ctx(fold),
+                                            INSTR_DIV_F,
+                                            (ast_expression*)fold->imm_float[1],
+                                            (ast_expression*)b
+                    )
+            );
+        }
+    }
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_mod(fold_t *fold, ast_value *a, ast_value *b) {
+    return (fold_can_2(a, b))
+                ? fold_constgen_float(fold, fmod(fold_immvalue_float(a), fold_immvalue_float(b)))
+                : NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_bor(fold_t *fold, ast_value *a, ast_value *b) {
+    if (isfloat(a)) {
+        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))));
+    } else {
+        if (isvector(b)) {
+            if (fold_can_2(a, b))
+                return fold_constgen_vector(fold, vec3_or(fold_immvalue_vector(a), fold_immvalue_vector(b)));
+        } else {
+            if (fold_can_2(a, b))
+                return fold_constgen_vector(fold, vec3_orvf(fold_immvalue_vector(a), fold_immvalue_float(b)));
+        }
+    }
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_band(fold_t *fold, ast_value *a, ast_value *b) {
+    if (isfloat(a)) {
+        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))));
+    } else {
+        if (isvector(b)) {
+            if (fold_can_2(a, b))
+                return fold_constgen_vector(fold, vec3_and(fold_immvalue_vector(a), fold_immvalue_vector(b)));
+        } else {
+            if (fold_can_2(a, b))
+                return fold_constgen_vector(fold, vec3_andvf(fold_immvalue_vector(a), fold_immvalue_float(b)));
+        }
+    }
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_xor(fold_t *fold, ast_value *a, ast_value *b) {
+    if (isfloat(a)) {
+        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))));
+    } else {
+        if (isvector(b)) {
+            if (fold_can_2(a, b))
+                return fold_constgen_vector(fold, vec3_xor(fold_immvalue_vector(a), fold_immvalue_vector(b)));
+        } else {
+            if (fold_can_2(a, b))
+                return fold_constgen_vector(fold, vec3_xorvf(fold_immvalue_vector(a), fold_immvalue_float(b)));
+        }
+    }
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_lshift(fold_t *fold, ast_value *a, ast_value *b) {
+    if (fold_can_2(a, b) && isfloats(a, b))
+        return fold_constgen_float(fold, (qcfloat_t)((qcuint_t)(fold_immvalue_float(a)) << (qcuint_t)(fold_immvalue_float(b))));
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_rshift(fold_t *fold, ast_value *a, ast_value *b) {
+    if (fold_can_2(a, b) && isfloats(a, b))
+        return fold_constgen_float(fold, (qcfloat_t)((qcuint_t)(fold_immvalue_float(a)) >> (qcuint_t)(fold_immvalue_float(b))));
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_andor(fold_t *fold, ast_value *a, ast_value *b, float expr) {
+    if (fold_can_2(a, b)) {
+        if (OPTS_FLAG(PERL_LOGIC)) {
+            if (fold_immediate_true(fold, a))
+                return (ast_expression*)b;
+        } else {
+            return fold_constgen_float (
+                fold,
+                ((expr) ? (fold_immediate_true(fold, a) || fold_immediate_true(fold, b))
+                        : (fold_immediate_true(fold, a) && fold_immediate_true(fold, b)))
+                            ? 1
+                            : 0
+            );
+        }
+    }
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_tern(fold_t *fold, ast_value *a, ast_value *b, ast_value *c) {
+    if (fold_can_1(a)) {
+        return fold_immediate_true(fold, a)
+                    ? (ast_expression*)b
+                    : (ast_expression*)c;
+    }
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_exp(fold_t *fold, ast_value *a, ast_value *b) {
+    if (fold_can_2(a, b))
+        return fold_constgen_float(fold, (qcfloat_t)powf(fold_immvalue_float(a), fold_immvalue_float(b)));
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_lteqgt(fold_t *fold, ast_value *a, ast_value *b) {
+    if (fold_can_2(a,b)) {
+        if (fold_immvalue_float(a) <  fold_immvalue_float(b)) return (ast_expression*)fold->imm_float[2];
+        if (fold_immvalue_float(a) == fold_immvalue_float(b)) return (ast_expression*)fold->imm_float[0];
+        if (fold_immvalue_float(a) >  fold_immvalue_float(b)) return (ast_expression*)fold->imm_float[1];
+    }
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_cmp(fold_t *fold, ast_value *a, ast_value *b, bool ne) {
+    if (fold_can_2(a, b)) {
+        return fold_constgen_float(
+                    fold,
+                    (ne) ? (fold_immvalue_float(a) != fold_immvalue_float(b))
+                         : (fold_immvalue_float(a) == fold_immvalue_float(b))
+                );
+    }
+    return NULL;
+}
+
+static GMQCC_INLINE ast_expression *fold_op_bnot(fold_t *fold, ast_value *a) {
+    if (isfloat(a)) {
+        if (fold_can_1(a))
+            return fold_constgen_float(fold, ~((qcint_t)fold_immvalue_float(a)));
+    } else {
+        if (isvector(a)) {
+            if (fold_can_1(a))
+                return fold_constgen_vector(fold, vec3_not(fold_immvalue_vector(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];
-    ast_value *c = (ast_value*)opexprs[2];
+    ast_value      *a = (ast_value*)opexprs[0];
+    ast_value      *b = (ast_value*)opexprs[1];
+    ast_value      *c = (ast_value*)opexprs[2];
+    ast_expression *e = NULL;
 
     /* can a fold operation be applied to this operator usage? */
     if (!info->folds)
@@ -369,75 +645,236 @@ ast_expression *fold_op(fold_t *fold, const oper_info *info, ast_expression **op
     switch(info->operands) {
         case 3: if(!c) return NULL;
         case 2: if(!b) return NULL;
+        case 1:
+        if(!a) {
+            compile_error(fold_ctx(fold), "internal error: fold_op no operands to fold\n");
+            return NULL;
+        }
     }
 
+    /*
+     * we could use a boolean and default case but ironically gcc produces
+     * invalid broken assembly from that operation. clang/tcc get it right,
+     * but interestingly ignore compiling this to a jump-table when I do that,
+     * this happens to be the most efficent method, since you have per-level
+     * granularity on the pointer check happening only for the case you check
+     * it in. Opposed to the default method which would involve a boolean and
+     * pointer check after wards.
+     */
+    #define fold_op_case(ARGS, ARGS_OPID, OP, ARGS_FOLD)    \
+        case opid##ARGS ARGS_OPID:                          \
+            if ((e = fold_op_##OP ARGS_FOLD)) {             \
+                ++opts_optimizationcount[OPTIM_CONST_FOLD]; \
+            }                                               \
+            return e
+
     switch(info->id) {
-        case opid2('-', 'P'):
-            return isfloat (a)             ? fold_constgen_float (fold, fold_immvalue_float(a))
-                 : isvector(a)             ? fold_constgen_vector(fold, vec3_neg(fold_immvalue_vector(a)))
-                 : NULL;
-        case opid2('!', 'P'):
-            return isfloat (a)             ? fold_constgen_float (fold, !fold_immvalue_float(a))
-                 : isvector(a)             ? fold_constgen_vector(fold, vec3_not(fold_immvalue_vector(a)))
-                 : isstring(a)             ? fold_constgen_float (fold, !fold_immvalue_string(a) || OPTS_FLAG(TRUE_EMPTY_STRINGS) ? 0 : !*fold_immvalue_string(a))
-                 : NULL;
-        case opid1('+'):
-            return isfloats(a,b)           ? fold_constgen_float (fold, fold_immvalue_float(a) + fold_immvalue_float(b))
-                 : isvectors(a,b)          ? fold_constgen_vector(fold, vec3_add(fold_immvalue_vector(a), fold_immvalue_vector(b)))
-                 : NULL;
-        case opid1('-'):
-            return isfloats(a,b)           ? fold_constgen_float (fold, fold_immvalue_float(a) - fold_immvalue_float(b))
-                 : isvectors(a,b)          ? fold_constgen_vector(fold, vec3_sub(fold_immvalue_vector(a), fold_immvalue_vector(b)))
-                 : NULL;
-        case opid1('%'):
-            return isfloats(a,b)           ? fold_constgen_float (fold, (qcfloat_t)(((qcint_t)fold_immvalue_float(a)) % ((qcint_t)fold_immvalue_float(b))))
-                 : NULL;
-        case opid1('|'):
-            return isfloats(a,b)           ? fold_constgen_float (fold, (qcfloat_t)(((qcint_t)fold_immvalue_float(a)) | ((qcint_t)fold_immvalue_float(b))))
-                 : NULL;
-        case opid1('&'):
-            return isfloats(a,b)           ? fold_constgen_float (fold, (qcfloat_t)(((qcint_t)fold_immvalue_float(a)) & ((qcint_t)fold_immvalue_float(b))))
-                 : NULL;
-        case opid1('^'):
-            return isfloats(a,b)           ? fold_constgen_float (fold, (qcfloat_t)(((qcint_t)fold_immvalue_float(a)) ^ ((qcint_t)fold_immvalue_float(b))))
-                 : isvectors(a,b)          ? fold_constgen_vector(fold, vec3_xor  (fold_immvalue_vector(a), fold_immvalue_vector(b)))
-                 : isvector(a)&&isfloat(b) ? fold_constgen_vector(fold, vec3_xorvf(fold_immvalue_vector(a), fold_immvalue_float (b)))
-                 : NULL;
-        case opid2('<','<'):
-            return isfloats(a,b)           ? fold_constgen_float (fold, (qcfloat_t)(((qcuint_t)(fold_immvalue_float(a)) << ((qcuint_t)fold_immvalue_float(b)))))
-                 : NULL;
-        case opid2('>','>'):
-            return isfloats(a,b)           ? fold_constgen_float (fold, (qcfloat_t)(((qcuint_t)(fold_immvalue_float(a)) >> ((qcuint_t)fold_immvalue_float(b)))))
-                 : NULL;
-        case opid2('*','*'):
-            return isfloats(a,b)           ? fold_constgen_float (fold, (qcfloat_t)powf(fold_immvalue_float(a), fold_immvalue_float(b)))
-                 : NULL;
-        case opid2('!','='):
-            return isfloats(a,b)           ? fold_constgen_float (fold, fold_immvalue_float(a) != fold_immvalue_float(b))
-                 : NULL;
-        case opid2('=','='):
-            return isfloats(a,b)           ? fold_constgen_float (fold, fold_immvalue_float(a) == fold_immvalue_float(b))
-                 : NULL;
-        case opid2('~','P'):
-            return isfloat(a)              ? fold_constgen_float (fold, ~(qcint_t)fold_immvalue_float(a))
-                 : NULL;
-
-        case opid1('*'): return fold_op_mul(fold, a, b);
-        case opid1('/'):
-            /* TODO: seperate function for this case */
-            return NULL;
-        case opid2('|','|'):
-            /* TODO: seperate function for this case */
-            return NULL;
-        case opid2('&','&'):
-            /* TODO: seperate function for this case */
-            return NULL;
-        case opid2('?',':'):
-            /* TODO: seperate function for this case */
-            return NULL;
-        case opid3('<','=','>'):
-            /* TODO: seperate function for this case */
-            return NULL;
+        fold_op_case(2, ('-', 'P'),    neg,    (fold, a));
+        fold_op_case(2, ('!', 'P'),    not,    (fold, a));
+        fold_op_case(1, ('+'),         add,    (fold, a, b));
+        fold_op_case(1, ('-'),         sub,    (fold, a, b));
+        fold_op_case(1, ('*'),         mul,    (fold, a, b));
+        fold_op_case(1, ('/'),         div,    (fold, a, b));
+        fold_op_case(1, ('%'),         mod,    (fold, a, b));
+        fold_op_case(1, ('|'),         bor,    (fold, a, b));
+        fold_op_case(1, ('&'),         band,   (fold, a, b));
+        fold_op_case(1, ('^'),         xor,    (fold, a, b));
+        fold_op_case(2, ('<', '<'),    lshift, (fold, a, b));
+        fold_op_case(2, ('>', '>'),    rshift, (fold, a, b));
+        fold_op_case(2, ('|', '|'),    andor,  (fold, a, b, true));
+        fold_op_case(2, ('&', '&'),    andor,  (fold, a, b, false));
+        fold_op_case(2, ('?', ':'),    tern,   (fold, a, b, c));
+        fold_op_case(2, ('*', '*'),    exp,    (fold, a, b));
+        fold_op_case(3, ('<','=','>'), lteqgt, (fold, a, b));
+        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");
     return NULL;
 }
+
+/*
+ * Constant folding for compiler intrinsics, simaler approach to operator
+ * folding, primarly: individual functions for each intrinsics to fold,
+ * and a generic selection function.
+ */
+static GMQCC_INLINE ast_expression *fold_intrin_mod(fold_t *fold, ast_value *lhs, ast_value *rhs) {
+    return fold_constgen_float(
+                fold,
+                fmodf(
+                    fold_immvalue_float(lhs),
+                    fold_immvalue_float(rhs)
+                )
+            );
+}
+
+static GMQCC_INLINE ast_expression *fold_intrin_pow(fold_t *fold, ast_value *lhs, ast_value *rhs) {
+    return fold_constgen_float(
+                fold,
+                powf(
+                    fold_immvalue_float(lhs),
+                    fold_immvalue_float(rhs)
+                )
+            );
+}
+
+static GMQCC_INLINE ast_expression *fold_intrin_exp(fold_t *fold, ast_value *value) {
+    return fold_constgen_float(fold, exp(fold_immvalue_float(value)));
+}
+
+static GMQCC_INLINE ast_expression *fold_intrin_isnan(fold_t *fold, ast_value *value) {
+    return fold_constgen_float(fold, isnan(fold_immvalue_float(value)) != 0.0f);
+}
+
+static GMQCC_INLINE ast_expression *fold_intrin_fabs(fold_t *fold, ast_value *value) {
+    return fold_constgen_float(fold, fabs(fold_immvalue_float(value)));
+}
+
+ast_expression *fold_intrin(fold_t *fold, const char *intrin, ast_expression **arg) {
+    ast_expression *ret = NULL;
+
+    if (!strcmp(intrin, "mod"))   ret = fold_intrin_mod  (fold, (ast_value*)arg[0], (ast_value*)arg[1]);
+    if (!strcmp(intrin, "pow"))   ret = fold_intrin_pow  (fold, (ast_value*)arg[0], (ast_value*)arg[1]);
+    if (!strcmp(intrin, "exp"))   ret = fold_intrin_exp  (fold, (ast_value*)arg[0]);
+    if (!strcmp(intrin, "isnan")) ret = fold_intrin_isnan(fold, (ast_value*)arg[0]);
+    if (!strcmp(intrin, "fabs"))  ret = fold_intrin_fabs (fold, (ast_value*)arg[0]);
+
+    if (ret)
+        ++opts_optimizationcount[OPTIM_CONST_FOLD];
+
+    return ret;
+}
+
+/*
+ * These are all the actual constant folding methods that happen in between
+ * the AST/IR stage of the compiler , i.e eliminating branches for const
+ * expressions, which is the only supported thing so far. We undefine the
+ * testing macros here because an ir_value is differant than an ast_value.
+ */
+#undef expect
+#undef isfloat
+#undef isstring
+#undef isvector
+#undef fold_immvalue_float
+#undef fold_immvalue_string
+#undef fold_immvalue_vector
+#undef fold_can_1
+#undef fold_can_2
+
+#define isfloat(X)              ((X)->vtype == TYPE_FLOAT)
+/*#define isstring(X)             ((X)->vtype == TYPE_STRING)*/
+/*#define isvector(X)             ((X)->vtype == TYPE_VECTOR)*/
+#define fold_immvalue_float(X)  ((X)->constval.vfloat)
+#define fold_immvalue_vector(X) ((X)->constval.vvec)
+/*#define fold_immvalue_string(X) ((X)->constval.vstring)*/
+#define fold_can_1(X)           ((X)->hasvalue && (X)->cvq == CV_CONST)
+/*#define fold_can_2(X,Y)         (fold_can_1(X) && fold_can_1(Y))*/
+
+static ast_expression *fold_superfluous(ast_expression *left, ast_expression *right, int op) {
+    ast_expression *swapped = NULL; /* using this as bool */
+    ast_value *load;
+
+    if (!ast_istype(right, ast_value) || !fold_can_1((load = (ast_value*)right))) {
+        swapped = left;
+        left    = right;
+        right   = swapped;
+    }
+
+    if (!ast_istype(right, ast_value) || !fold_can_1((load = (ast_value*)right)))
+        return NULL;
+
+    switch (op) {
+        case INSTR_DIV_F:
+            if (swapped)
+                return NULL;
+        case INSTR_MUL_F:
+            if (fold_immvalue_float(load) == 1.0f) {
+                ++opts_optimizationcount[OPTIM_PEEPHOLE];
+                ast_unref(right);
+                return left;
+            }
+            break;
+
+
+        case INSTR_ADD_F:
+        case INSTR_SUB_F:
+            if (fold_immvalue_float(load) == 0.0f) {
+                ++opts_optimizationcount[OPTIM_PEEPHOLE];
+                ast_unref(right);
+                return left;
+            }
+            break;
+
+        case INSTR_MUL_V:
+            if (vec3_cmp(fold_immvalue_vector(load), vec3_create(1, 1, 1))) {
+                ++opts_optimizationcount[OPTIM_PEEPHOLE];
+                ast_unref(right);
+                return left;
+            }
+            break;
+
+        case INSTR_ADD_V:
+        case INSTR_SUB_V:
+            if (vec3_cmp(fold_immvalue_vector(load), vec3_create(0, 0, 0))) {
+                ++opts_optimizationcount[OPTIM_PEEPHOLE];
+                ast_unref(right);
+                return left;
+            }
+            break;
+    }
+
+    return NULL;
+}
+
+ast_expression *fold_binary(lex_ctx_t ctx, int op, ast_expression *left, ast_expression *right) {
+    ast_expression *ret = fold_superfluous(left, right, op);
+    if (ret)
+        return ret;
+    return (ast_expression*)ast_binary_new(ctx, op, left, right);
+}
+
+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;
+        ir_value               *dummy;
+        bool                    istrue  = (fold_immvalue_float(condval) != 0.0f && branch->on_true);
+        bool                    isfalse = (fold_immvalue_float(condval) == 0.0f && branch->on_false);
+        ast_expression         *path    = (istrue)  ? branch->on_true  :
+                                          (isfalse) ? branch->on_false : NULL;
+        if (!path) {
+            /*
+             * no path to take implies that the evaluation is if(0) and there
+             * is no else block. so eliminate all the code.
+             */
+            ++opts_optimizationcount[OPTIM_CONST_FOLD_DCE];
+            return true;
+        }
+
+        if (!(elide = ir_function_create_block(ast_ctx(branch), func->ir_func, ast_function_label(func, ((istrue) ? "ontrue" : "onfalse")))))
+            return false;
+        if (!(*(cgen = path->codegen))((ast_expression*)path, func, false, &dummy))
+            return false;
+        if (!ir_block_create_jump(func->curblock, ast_ctx(branch), elide))
+            return false;
+        /*
+         * now the branch has been eliminated and the correct block for the constant evaluation
+         * is expanded into the current block for the function.
+         */
+        func->curblock = elide;
+        ++opts_optimizationcount[OPTIM_CONST_FOLD_DCE];
+        return true;
+    }
+    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);
+}