JIT: eliminate check for undefined constant if there is a persistent constant

Author: dstogov

ext/opcache/jit/zend_jit.c

@@ -576,6 +576,25 @@ static bool zend_jit_may_avoid_refcounting(const zend_op *opline)
 	return 0;
 }
 
+static bool zend_jit_is_persistent_constant(zval *key, uint32_t flags)
+{
+	zval *zv;
+	zend_constant *c = NULL;
+
+	/* null/true/false are resolved during compilation, so don't check for them here. */
+	zv = zend_hash_find_known_hash(EG(zend_constants), Z_STR_P(key));
+	if (zv) {
+		c = (zend_constant*)Z_PTR_P(zv);
+	} else if (flags & IS_CONSTANT_UNQUALIFIED_IN_NAMESPACE) {
+		key++;
+		zv = zend_hash_find_known_hash(EG(zend_constants), Z_STR_P(key));
+		if (zv) {
+			c = (zend_constant*)Z_PTR_P(zv);
+		}
+	}
+	return c && (ZEND_CONSTANT_FLAGS(c) & CONST_PERSISTENT);
+}
+
 static zend_property_info* zend_get_known_property_info(const zend_op_array *op_array, zend_class_entry *ce, zend_string *member, bool on_this, zend_string *filename)
 {
 	zend_property_info *info = NULL;

ext/opcache/jit/zend_jit_arm64.dasc

@@ -13892,10 +13892,12 @@ static int zend_jit_fetch_constant(dasm_State          **Dst,
 	|	MEM_ACCESS_64_WITH_UOFFSET ldr, REG0, FCARG1x, opline->extended_value, TMP1
 	|	// if (c != NULL)
 	|	cbz REG0, >9
-	|	// if (!IS_SPECIAL_CACHE_VAL(c))
-	||	ZEND_ASSERT(CACHE_SPECIAL == 1);
-	|	TST_64_WITH_ONE REG0
-	|	bne >9
+	if (!zend_jit_is_persistent_constant(zv, opline->op1.num)) {
+		|	// if (!IS_SPECIAL_CACHE_VAL(c))
+		||	ZEND_ASSERT(CACHE_SPECIAL == 1);
+		|	TST_64_WITH_ONE REG0
+		|	bne >9
+	}
 	|8:
 
 	if ((res_info & MAY_BE_GUARD) && JIT_G(current_frame)) {

ext/opcache/jit/zend_jit_x86.dasc

@@ -14740,9 +14740,11 @@ static int zend_jit_fetch_constant(dasm_State          **Dst,
 	|	// if (c != NULL)
 	|	test r0, r0
 	|	jz >9
-	|	// if (!IS_SPECIAL_CACHE_VAL(c))
-	|	test r0, CACHE_SPECIAL
-	|	jnz >9
+	if (!zend_jit_is_persistent_constant(zv, opline->op1.num)) {
+		|	// if (!IS_SPECIAL_CACHE_VAL(c))
+		|	test r0, CACHE_SPECIAL
+		|	jnz >9
+	}
 	|8:
 
 	if ((res_info & MAY_BE_GUARD) && JIT_G(current_frame)) {