Respect RC_INFERENCE during DFG construction

To avoid inserting phis that are only relevant with rc inference enabled. Suprisingly, this affects only 0.8% of phis.

Author: nikic

ext/opcache/Optimizer/zend_dfg.c

@@ -20,7 +20,7 @@
 #include "zend_compile.h"
 #include "zend_dfg.h"
 
-int zend_build_dfg(const zend_op_array *op_array, const zend_cfg *cfg, zend_dfg *dfg) /* {{{ */
+int zend_build_dfg(const zend_op_array *op_array, const zend_cfg *cfg, zend_dfg *dfg, uint32_t build_flags) /* {{{ */
 {
 int set_size;
 zend_basic_block *blocks = cfg->blocks;
@@ -89,18 +89,33 @@ int zend_build_dfg(const zend_op_array *op_array, const zend_cfg *cfg, zend_dfg
 }
 if (opline->op1_type == IS_CV) {
 switch (opline->opcode) {
+case ZEND_ADD_ARRAY_ELEMENT:
+case ZEND_INIT_ARRAY:
+if ((build_flags & ZEND_SSA_RC_INFERENCE)
+|| (opline->extended_value & ZEND_ARRAY_ELEMENT_REF)) {
+goto op1_def;
+}
+goto op1_use;
+case ZEND_FE_RESET_R:
+if (build_flags & ZEND_SSA_RC_INFERENCE) {
+goto op1_def;
+}
+goto op1_use;
+case ZEND_YIELD:
+if ((build_flags & ZEND_SSA_RC_INFERENCE)
+|| (op_array->fn_flags & ZEND_ACC_RETURN_REFERENCE)) {
+goto op1_def;
+}
+goto op1_use;
 case ZEND_ASSIGN:
 case ZEND_ASSIGN_REF:
 case ZEND_BIND_GLOBAL:
 case ZEND_BIND_STATIC:
 case ZEND_SEND_VAR_EX:
 case ZEND_SEND_REF:
 case ZEND_SEND_VAR_NO_REF:
-case ZEND_FE_RESET_R:
 case ZEND_FE_RESET_RW:
-case ZEND_ADD_ARRAY_ELEMENT:
-case ZEND_INIT_ARRAY:
-case ZEND_YIELD:
+op1_def:
 if (!DFG_ISSET(use, set_size, j, EX_VAR_TO_NUM(opline->op1.var))) {
 // FIXME: include into "use" to ...?
 DFG_SET(use, set_size, j, EX_VAR_TO_NUM(opline->op1.var));
@@ -141,6 +156,7 @@ int zend_build_dfg(const zend_op_array *op_array, const zend_cfg *cfg, zend_dfg
 case ZEND_FETCH_OBJ_UNSET:
 DFG_SET(gen, set_size, j, EX_VAR_TO_NUM(opline->op1.var));
 default:
+op1_use:
 if (!DFG_ISSET(def, set_size, j, EX_VAR_TO_NUM(opline->op1.var))) {
 DFG_SET(use, set_size, j, EX_VAR_TO_NUM(opline->op1.var));
 }
@@ -154,10 +170,19 @@ int zend_build_dfg(const zend_op_array *op_array, const zend_cfg *cfg, zend_dfg
 if (opline->op2_type == IS_CV) {
 switch (opline->opcode) {
 case ZEND_ASSIGN:
+if (build_flags & ZEND_SSA_RC_INFERENCE) {
+goto op2_def;
+}
+goto op2_use;
+case ZEND_BIND_LEXICAL:
+if ((build_flags & ZEND_SSA_RC_INFERENCE) || opline->extended_value) {
+goto op2_def;
+}
+goto op2_use;
 case ZEND_ASSIGN_REF:
 case ZEND_FE_FETCH_R:
 case ZEND_FE_FETCH_RW:
-case ZEND_BIND_LEXICAL:
+op2_def:
 if (!DFG_ISSET(use, set_size, j, EX_VAR_TO_NUM(opline->op2.var))) {
 // FIXME: include into "use" to ...?
 DFG_SET(use, set_size, j, EX_VAR_TO_NUM(opline->op2.var));
@@ -166,6 +191,7 @@ int zend_build_dfg(const zend_op_array *op_array, const zend_cfg *cfg, zend_dfg
 DFG_SET(gen, set_size, j, EX_VAR_TO_NUM(opline->op2.var));
 break;
 default:
+op2_use:
 if (!DFG_ISSET(def, set_size, j, EX_VAR_TO_NUM(opline->op2.var))) {
 DFG_SET(use, set_size, j, EX_VAR_TO_NUM(opline->op2.var));
 }

ext/opcache/Optimizer/zend_dfg.h

@@ -44,7 +44,7 @@ typedef struct _zend_dfg {
 
 BEGIN_EXTERN_C()
 
-int zend_build_dfg(const zend_op_array *op_array, const zend_cfg *cfg, zend_dfg *dfg);
+int zend_build_dfg(const zend_op_array *op_array, const zend_cfg *cfg, zend_dfg *dfg, uint32_t build_flags);
 
 END_EXTERN_C()
 

ext/opcache/Optimizer/zend_ssa.c

@@ -532,7 +532,7 @@ int zend_build_ssa(zend_arena **arena, const zend_op_array *op_array, uint32_t b
 dfg.in = dfg.use + set_size * blocks_count;
 dfg.out = dfg.in + set_size * blocks_count;
 
-if (zend_build_dfg(op_array, &ssa->cfg, &dfg) != SUCCESS) {
+if (zend_build_dfg(op_array, &ssa->cfg, &dfg, build_flags) != SUCCESS) {
 free_alloca(dfg.tmp, dfg_use_heap);
 return FAILURE;
 }