Fixed bug #81226 (Integer overflow behavior is different with JIT ena…

…bled)
php · Jul 21, 2021 · 053c56f · 053c56f
1 parent 0ba6dde
commit 053c56f
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Showing 3 changed files with 40 additions and 22 deletions.
diff --git a/NEWS b/NEWS
@@ -22,6 +22,8 @@ PHP                                                                        NEWS
   . Fixed Bug #81255 (Memory leak in PHPUnit with functional JIT). (Dmitry)
   . Fixed Bug #80959 (infinite loop in building cfg during JIT compilation)
     (Nikita, Dmitry)
+  . Fixed bug #81226 (Integer overflow behavior is different with JIT
+    enabled). (Dmitry)
 
 - Standard:
   . Fixed bug #72146 (Integer overflow on substr_replace). (cmb)

diff --git a/ext/opcache/jit/zend_jit.c b/ext/opcache/jit/zend_jit.c
@@ -193,6 +193,12 @@ static zend_bool zend_long_is_power_of_two(zend_long x)
 	return (x > 0) && !(x & (x - 1));
 }
 
+static zend_always_inline uint32_t zend_long_floor_log2(zend_long x)
+{
+	ZEND_ASSERT(zend_long_is_power_of_two(x));
+	return zend_ulong_ntz(x);
+}
+
 #define OP_RANGE(ssa_op, opN) \
 	(((opline->opN##_type & (IS_TMP_VAR|IS_VAR|IS_CV)) && \
 	  ssa->var_info && \

diff --git a/ext/opcache/jit/zend_jit_x86.dasc b/ext/opcache/jit/zend_jit_x86.dasc
@@ -4234,7 +4234,7 @@ static int zend_jit_math_long_long(dasm_State    **Dst,
 		} else {
 			result_reg = Z_REG(res_addr);
 		}
-	} else if (Z_MODE(op1_addr) == IS_REG && Z_LAST_USE(op1_addr)) {
+	} else if (Z_MODE(op1_addr) == IS_REG && Z_LAST_USE(op1_addr) && !may_overflow) {
 		result_reg = Z_REG(op1_addr);
 	} else if (Z_REG(res_addr) != ZREG_R0) {
 		result_reg = ZREG_R0;
@@ -4245,32 +4245,42 @@ static int zend_jit_math_long_long(dasm_State    **Dst,
 	}
 
 	if (opcode == ZEND_MUL &&
-		((Z_MODE(op2_addr) == IS_CONST_ZVAL &&
-		IS_SIGNED_32BIT(Z_LVAL_P(Z_ZV(op2_addr))) &&
-		is_power_of_two(Z_LVAL_P(Z_ZV(op2_addr)))) ||
-		(Z_MODE(op1_addr) == IS_CONST_ZVAL &&
-		IS_SIGNED_32BIT(Z_LVAL_P(Z_ZV(op1_addr))) &&
-		is_power_of_two(Z_LVAL_P(Z_ZV(op1_addr)))))) {
-		if (Z_MODE(op2_addr) == IS_CONST_ZVAL) {
-			if (Z_MODE(op1_addr) == IS_REG && Z_LVAL_P(Z_ZV(op2_addr)) == 2) {
-				|	lea Ra(result_reg), [Ra(Z_REG(op1_addr))+Ra(Z_REG(op1_addr))]
-			} else {
-				|	GET_ZVAL_LVAL result_reg, op1_addr
-				|	shl Ra(result_reg), floor_log2(Z_LVAL_P(Z_ZV(op2_addr)))
-			}
+			Z_MODE(op2_addr) == IS_CONST_ZVAL &&
+			Z_LVAL_P(Z_ZV(op2_addr)) == 2) {
+		if (Z_MODE(op1_addr) == IS_REG && !may_overflow) {
+			|	lea Ra(result_reg), [Ra(Z_REG(op1_addr))+Ra(Z_REG(op1_addr))]
 		} else {
-			if (Z_MODE(op2_addr) == IS_REG && Z_LVAL_P(Z_ZV(op1_addr)) == 2) {
-				|	lea Ra(result_reg), [Ra(Z_REG(op2_addr))+Ra(Z_REG(op2_addr))]
-			} else {
-				|	GET_ZVAL_LVAL result_reg, op2_addr
-				|	shl Ra(result_reg), floor_log2(Z_LVAL_P(Z_ZV(op1_addr)))
-			}
+			|	GET_ZVAL_LVAL result_reg, op1_addr
+			|	add Ra(result_reg), Ra(result_reg)
 		}
+	} else if (opcode == ZEND_MUL &&
+			Z_MODE(op2_addr) == IS_CONST_ZVAL &&
+			!may_overflow &&
+			Z_LVAL_P(Z_ZV(op2_addr)) > 0 &&
+			zend_long_is_power_of_two(Z_LVAL_P(Z_ZV(op2_addr)))) {
+		|	GET_ZVAL_LVAL result_reg, op1_addr
+		|	shl Ra(result_reg), zend_long_floor_log2(Z_LVAL_P(Z_ZV(op2_addr)))
+	} else if (opcode == ZEND_MUL &&
+			Z_MODE(op1_addr) == IS_CONST_ZVAL &&
+			Z_LVAL_P(Z_ZV(op1_addr)) == 2) {
+		if (Z_MODE(op2_addr) == IS_REG && !may_overflow) {
+			|	lea Ra(result_reg), [Ra(Z_REG(op2_addr))+Ra(Z_REG(op2_addr))]
+		} else {
+			|	GET_ZVAL_LVAL result_reg, op2_addr
+			|	add Ra(result_reg), Ra(result_reg)
+		}
+	} else if (opcode == ZEND_MUL &&
+			Z_MODE(op1_addr) == IS_CONST_ZVAL &&
+			!may_overflow &&
+			Z_LVAL_P(Z_ZV(op1_addr)) > 0 &&
+			zend_long_is_power_of_two(Z_LVAL_P(Z_ZV(op1_addr)))) {
+		|	GET_ZVAL_LVAL result_reg, op2_addr
+		|	shl Ra(result_reg), zend_long_floor_log2(Z_LVAL_P(Z_ZV(op1_addr)))
 	} else if (opcode == ZEND_DIV &&
 			(Z_MODE(op2_addr) == IS_CONST_ZVAL &&
-			is_power_of_two(Z_LVAL_P(Z_ZV(op2_addr))))) {
+			zend_long_is_power_of_two(Z_LVAL_P(Z_ZV(op2_addr))))) {
 		|	GET_ZVAL_LVAL result_reg, op1_addr
-		|	shr Ra(result_reg), floor_log2(Z_LVAL_P(Z_ZV(op2_addr)))
+		|	shr Ra(result_reg), zend_long_floor_log2(Z_LVAL_P(Z_ZV(op2_addr)))
 	} else if (opcode == ZEND_ADD &&
 			!may_overflow &&
 			Z_MODE(op1_addr) == IS_REG &&