From: Nikita Popov <nikita.ppv@gmail.com>
Date: Tue, 17 Nov 2020 09:20:23 +0000 (+0100)
Subject: Merge branch 'PHP-7.4' into PHP-8.0
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9cfb5261e4b48e0520fc7e085e6eb189eeb33b3d;p=php

Merge branch 'PHP-7.4' into PHP-8.0

* PHP-7.4:
  Fix incorrectly optimized out live range
---

9cfb5261e4b48e0520fc7e085e6eb189eeb33b3d
diff --cc ext/opcache/Optimizer/zend_optimizer.c
index b0efcc9026,7871fa3c8e..c80992ed8d
--- a/ext/opcache/Optimizer/zend_optimizer.c
+++ b/ext/opcache/Optimizer/zend_optimizer.c
@@@ -1350,14 -1312,25 +1350,24 @@@ static void zend_adjust_fcall_stack_siz
  static zend_bool needs_live_range(zend_op_array *op_array, zend_op *def_opline) {
  	zend_func_info *func_info = ZEND_FUNC_INFO(op_array);
  	zend_ssa_op *ssa_op = &func_info->ssa.ops[def_opline - op_array->opcodes];
- 	if (ssa_op->result_def >= 0) {
- 		uint32_t type = func_info->ssa.var_info[ssa_op->result_def].type;
- 		return (type & (MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_REF)) != 0;
+ 	int ssa_var = ssa_op->result_def;
+ 	if (ssa_var < 0) {
+ 		/* Be conservative. */
+ 		return 1;
  	}
- 	return 1;
+ 
+ 	/* If the variable is used by a PHI, this may be the assignment of the final branch of a
+ 	 * ternary/etc structure. While this is where the live range starts, the value from the other
+ 	 * branch may also be used. As such, use the type of the PHI node for the following check. */
+ 	if (func_info->ssa.vars[ssa_var].phi_use_chain) {
+ 		ssa_var = func_info->ssa.vars[ssa_var].phi_use_chain->ssa_var;
+ 	}
+ 
+ 	uint32_t type = func_info->ssa.var_info[ssa_var].type;
+ 	return (type & (MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_REF)) != 0;
  }
 -#endif
  
 -int zend_optimize_script(zend_script *script, zend_long optimization_level, zend_long debug_level)
 +void zend_foreach_op_array(zend_script *script, zend_op_array_func_t func, void *context)
  {
  	zend_class_entry *ce;
  	zend_string *key;