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Improve fix for bug #75687

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Adding an (incorrect) UNDEF here may cause subsequent narrowing in
other places.

Instead, let's try to handle this edge-case once for all
instructions...
This commit is contained in:
Nikita Popov
2017-12-16 21:11:40 +01:00
parent f01d5faf30
commit 8a4532319d
1 changed files with 18 additions and 3 deletions
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21
ext/opcache/Optimizer/zend_inference.c
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@@ -2154,6 +2154,24 @@ 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:
@@ -3338,9 +3356,6 @@ int zend_infer_types_ex(const zend_op_array *op_array, const zend_script *script
/* Ignore the constraint (either ce instanceof constraint->ce or
* they are unrelated, as far as we can statically determine) */
}
} else if ((tmp & MAY_BE_ANY) == 0) {
/* FIXME: usage in unreachable block */
tmp |= MAY_BE_UNDEF;
}
}