Backport narrowing fix to 7.1

This is a cherry-pick of 8a4532319dfae83ff16b2d2bbfeed062924c3c27.

diff --git a/ext/opcache/Optimizer/zend_inference.c b/ext/opcache/Optimizer/zend_inference.c
index db232dff72a39d941ac993e7e8e7610a78c0a48a..aeb30c8ec591fdffb707d872c61426d0269a986d 100644 (file)
--- a/ext/opcache/Optimizer/zend_inference.c
+++ b/ext/opcache/Optimizer/zend_inference.c
@@ -2157,6 +2157,24 @@ static int zend_update_type_info(const zend_op_array *op_array,
        t1 = OP1_INFO();
        t2 = OP2_INFO();
 
+       /* If one of the operands cannot have any type, this means the operand derives from
+        * unreachable code. Propagate the empty result early, so that that the following
+        * code may assume that operands have at least one type. */
+       if (!(t1 & (MAY_BE_ANY|MAY_BE_UNDEF|MAY_BE_CLASS|MAY_BE_ERROR))
+                       || !(t2 & (MAY_BE_ANY|MAY_BE_UNDEF|MAY_BE_CLASS|MAY_BE_ERROR))) {
+               tmp = 0;
+               if (ssa_ops[i].result_def >= 0) {
+                       UPDATE_SSA_TYPE(tmp, ssa_ops[i].result_def);
+               } 
+               if (ssa_ops[i].op1_def >= 0) { 
+                       UPDATE_SSA_TYPE(tmp, ssa_ops[i].op1_def);
+               } 
+               if (ssa_ops[i].op2_def >= 0) { 
+                       UPDATE_SSA_TYPE(tmp, ssa_ops[i].op2_def);
+               } 
+               return 1;
+       } 
+
        switch (opline->opcode) {
                case ZEND_ADD:
                case ZEND_SUB: