Don't undef result operand if there is none

The mod_by_zero and negative_shift helper may also be used by
ASSIGN_OP, in which case there is not necessarily a result operand.
If the stars aligned just right, this used to clobber other parts
of the call frame.

For these two helpers, check whether the result_type is TMP/VAR
before setting to UNDEF:

Author: nikic

ext/opcache/jit/zend_jit_x86.dasc

@@ -558,6 +558,15 @@ static void* dasm_labels[zend_lb_MAX];
 |	SET_Z_TYPE_INFO FP + r0, IS_UNDEF
 |.endmacro
 
+|.macro UNDEF_OPLINE_RESULT_IF_USED
+|	mov r0, EX->opline
+|	test byte OP:r0->result_type, (IS_TMP_VAR|IS_VAR)
+|	jz >1
+|	mov eax, dword OP:r0->result.var
+|	SET_Z_TYPE_INFO FP + r0, IS_UNDEF
+|1:
+|.endmacro
+
 |.macro SSE_AVX_INS, sse_ins, avx_ins, op1, op2
 ||	if (CAN_USE_AVX()) {
 |		avx_ins op1, op2
@@ -2139,7 +2148,7 @@ static int zend_jit_undefined_function_stub(dasm_State **Dst)
 static int zend_jit_negative_shift_stub(dasm_State **Dst)
 {
 	|->negative_shift:
-	|	UNDEF_OPLINE_RESULT
+	|	UNDEF_OPLINE_RESULT_IF_USED
 	|.if X64
 		|.if WIN
 		|	LOAD_ADDR CARG1, &zend_ce_arithmetic_error
@@ -2168,7 +2177,7 @@ static int zend_jit_negative_shift_stub(dasm_State **Dst)
 static int zend_jit_mod_by_zero_stub(dasm_State **Dst)
 {
 	|->mod_by_zero:
-	|	UNDEF_OPLINE_RESULT
+	|	UNDEF_OPLINE_RESULT_IF_USED
 	|.if X64
 		|.if WIN
 		|	LOAD_ADDR CARG1, &zend_ce_division_by_zero_error

ext/opcache/tests/jit/assign_op_001.phpt

@@ -0,0 +1,29 @@
+--TEST--
+JIT ASSIGN_OP: 001
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.file_update_protection=0
+opcache.jit_buffer_size=1M
+--FILE--
+<?php
+function test1($a) {
+    $a %= 0;
+}
+function test2($a) {
+    $a <<= -1;
+}
+try {
+    test1(1);
+} catch (DivisionByZeroError $e) {
+    echo $e->getMessage(), "\n";
+}
+try {
+    test2(1);
+} catch (ArithmeticError $e) {
+    echo $e->getMessage(), "\n";
+}
+?>
+--EXPECT--
+Modulo by zero
+Bit shift by negative number