Short answer. It depends on intent to aid the enemy. Article 120 punishes correspondence with an enemy country by penalties ranging from prisión correccional up to reclusión temporal, but if you intended to aid the enemy by giving useful information, the penalty is reclusión temporal to death — though Republic Act No. 9346 has since replaced death with reclusión perpetua.
What the law says
Any person, who in time of war, shall have correspondence with an enemy country or territory occupied by enemy troops shall be punished:
Revised Penal Code, Article 120 — Correspondence With Hostile Country. Read the full provision →
What the law says
1. By prision correccional, if the correspondence has been prohibited by the Government; 2. By prision mayor, if such correspondence be carried on in ciphers or conventional signs; and 3. By reclusion temporal, if notice or information be given thereby which might be useful to the enemy.
Revised Penal Code, Article 120 — Correspondence With Hostile Country. Read the full provision →
What the law says
If the offender intended to aid the enemy by giving such notice or information he shall suffer the penalty of reclusion temporal to death.
Revised Penal Code, Article 120 — Correspondence With Hostile Country. Read the full provision →
The base offense: correspondence with an enemy country
Article 120 covers any person, who in time of war, shall have correspondence with an enemy country or territory occupied by enemy troops. The article does not require that you actually succeeded in helping the enemy — the underlying offense is having correspondence with the enemy during wartime, with the specific penalty then depending on the circumstances of that correspondence, described in three separate numbered penalties.
The three escalating penalties for correspondence alone
Those three penalties escalate depending on what the correspondence involved. It is punished by prision correccional, if the correspondence has been prohibited by the Government; by prision mayor, if such correspondence be carried on in ciphers or conventional signs; and by reclusion temporal, if notice or information be given thereby which might be useful to the enemy. Each level reflects a more serious form of the same underlying conduct — plain prohibited correspondence, coded correspondence, and correspondence that actually conveys militarily useful information.
The heavier penalty when the intent is to aid the enemy
Your question describes passing information specifically to help the enemy, which the article treats as the most serious version of this offense. It states that if the offender intended to aid the enemy by giving such notice or information he shall suffer the penalty of reclusion temporal to death. So proven intent to aid the enemy, on top of giving useful notice or information, pushes the applicable penalty range up to the harshest bracket the article provides.
Why 'death' in the text no longer means death
That said, 'death' in this article's text no longer reflects current law. Republic Act No. 9346, enacted in 2006, prohibits the imposition of the death penalty in the Philippines altogether. Where the Revised Penal Code's own terms call for death, current law substitutes reclusión perpetua instead. So the actual maximum penalty someone could face under this article today tops out at reclusión perpetua, not death, despite what the article's original text still says.