From: Dmitry Stogov <dmitry@zend.com>
Date: Thu, 24 Dec 2015 08:06:02 +0000 (+0300)
Subject: Add another DFA optimization pattern (ASSIGN -> QM_ASSING)
X-Git-Tag: php-7.1.0alpha1~617^2~147
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=3d88a64e0ce3bc9ddb7a566f98b1bed2ba0ae4fd;p=php

Add another DFA optimization pattern (ASSIGN -> QM_ASSING)
---

diff --git a/ext/opcache/Optimizer/dfa_pass.c b/ext/opcache/Optimizer/dfa_pass.c
index 0e7a9329c7..ac7a193675 100644
--- a/ext/opcache/Optimizer/dfa_pass.c
+++ b/ext/opcache/Optimizer/dfa_pass.c
@@ -131,57 +131,98 @@ void optimize_dfa(zend_op_array *op_array, zend_optimizer_ctx *ctx)
 	//TODO: Add optimization patterns ???
 	if (ssa.var_info) {
 		int i;
-		// 1: #1.T  = OP_Y                                   |  #3.CV = OP_Y
-		// 2: ASSIGN #2.CV [undef,null,bool] -> #3.cv, #1.T  |  NOP
+		int remove_nops = 0;
+
+		// 1: #1.T  = OP_Y                                |  #3.CV = OP_Y
+		// 2: ASSIGN #2.CV [undef,scalar] -> #3.CV, #1.T  |  NOP
+		// --
+		// 2: ASSIGN #2.CV [undef,scalar] -> #3.CV, C     |  3.CV = QM_ASSIGN C
+		// --
+		// 2: ASSIGN #2.CV [undef,scalar] -> #3.CV, #1.CV |  3.CV = QM_ASSIGN #1.CV
+
 		for (i = 0; i < ssa.vars_count; i++) {
 			int op2 = ssa.vars[i].definition;
 
 			if (op2 >= 0
 			 && op_array->opcodes[op2].opcode == ZEND_ASSIGN
 			 && op_array->opcodes[op2].op1_type == IS_CV
-			 && (op_array->opcodes[op2].op2_type & (IS_TMP_VAR|IS_VAR))
 			 && !RETURN_VALUE_USED(&op_array->opcodes[op2])
 			) {
-
-				int var1 = ssa.ops[op2].op2_use;
 				int var2 = ssa.ops[op2].op1_use;
 
-				if (var1 >= 0
-				 && var2 >= 0
+				if (var2 >= 0
 				 && !(ssa.var_info[var2].type & (MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_REF))
-				 && !(ssa.var_info[var1].type & MAY_BE_REF)
-				 && ssa.vars[var1].definition >= 0
-				 && ssa.ops[ssa.vars[var1].definition].result_def == var1
-				 && ssa.ops[ssa.vars[var1].definition].result_use < 0
-				 && ssa.vars[var1].use_chain == op2
-				 && ssa.ops[op2].op2_use_chain < 0
-				 && !ssa.vars[var1].phi_use_chain
-				 && !ssa.vars[var1].sym_use_chain
 				) {
-					int op1 = ssa.vars[var1].definition;
-					int var3 = i;
-
-					if (zend_ssa_unlink_use_chain(&ssa, op2, var2)) {
-						/* Reconstruct SSA */
-						ssa.vars[var3].definition = op1;
-						ssa.ops[op1].result_def = var3;
-
-						ssa.vars[var1].definition = -1;
-						ssa.vars[var1].use_chain = -1;
-
-						ssa.ops[op2].op1_use = -1;
-						ssa.ops[op2].op2_use = -1;
-						ssa.ops[op2].op1_def = -1;
-						ssa.ops[op2].op1_use_chain = -1;
-
-						/* Update opcodes */
-						op_array->opcodes[op1].result_type = op_array->opcodes[op2].op1_type;
-						op_array->opcodes[op1].result.var = op_array->opcodes[op2].op1.var;
-						MAKE_NOP(&op_array->opcodes[op2]);
+
+					if (op_array->opcodes[op2].op2_type & (IS_TMP_VAR|IS_VAR)) {
+						int var1 = ssa.ops[op2].op2_use;
+
+						if (var1 >= 0
+						 && !(ssa.var_info[var1].type & MAY_BE_REF)
+						 && ssa.vars[var1].definition >= 0
+						 && ssa.ops[ssa.vars[var1].definition].result_def == var1
+						 && ssa.ops[ssa.vars[var1].definition].result_use < 0
+						 && ssa.vars[var1].use_chain == op2
+						 && ssa.ops[op2].op2_use_chain < 0
+						 && !ssa.vars[var1].phi_use_chain
+						 && !ssa.vars[var1].sym_use_chain
+						) {
+							int op1 = ssa.vars[var1].definition;
+							int var3 = i;
+
+							if (zend_ssa_unlink_use_chain(&ssa, op2, var2)) {
+								/* Reconstruct SSA */
+								ssa.vars[var3].definition = op1;
+								ssa.ops[op1].result_def = var3;
+
+								ssa.vars[var1].definition = -1;
+								ssa.vars[var1].use_chain = -1;
+
+								ssa.ops[op2].op1_use = -1;
+								ssa.ops[op2].op2_use = -1;
+								ssa.ops[op2].op1_def = -1;
+								ssa.ops[op2].op1_use_chain = -1;
+
+								/* Update opcodes */
+								op_array->opcodes[op1].result_type = op_array->opcodes[op2].op1_type;
+								op_array->opcodes[op1].result.var = op_array->opcodes[op2].op1.var;
+								MAKE_NOP(&op_array->opcodes[op2]);
+								remove_nops = 1;
+							}
+						}
+					} else if (op_array->opcodes[op2].op2_type == IS_CONST
+					 || (op_array->opcodes[op2].op2_type == IS_CV
+					     && ssa.ops[op2].op2_use >= 0
+					     && ssa.ops[op2].op2_def < 0
+					     && !(ssa.var_info[ssa.ops[op2].op2_use].type & MAY_BE_REF))
+					) {
+						int var3 = i;
+
+						if (zend_ssa_unlink_use_chain(&ssa, op2, var2)) {
+							/* Reconstruct SSA */
+							ssa.ops[op2].result_def = var3;
+							ssa.ops[op2].op1_def = -1;
+							ssa.ops[op2].op1_use = ssa.ops[op2].op2_use;
+							ssa.ops[op2].op1_use_chain = ssa.ops[op2].op2_use_chain;
+							ssa.ops[op2].op2_use = -1;
+							ssa.ops[op2].op2_use_chain = -1;
+
+							/* Update opcode */
+							op_array->opcodes[op2].result_type = op_array->opcodes[op2].op1_type;
+							op_array->opcodes[op2].result.var = op_array->opcodes[op2].op1.var;
+							op_array->opcodes[op2].op1_type = op_array->opcodes[op2].op2_type;
+							op_array->opcodes[op2].op1.var = op_array->opcodes[op2].op2.var;
+							op_array->opcodes[op2].op2_type = IS_UNUSED;
+							op_array->opcodes[op2].op2.var = 0;
+							op_array->opcodes[op2].opcode = ZEND_QM_ASSIGN;
+						}
 					}
 				}
 			}
 		}
+		if (remove_nops) {
+			// TODO: remove nop???
+		}
 	}