fix(S3FIFO): keep the 64-bit frequency when the main FIFO evicts

[windsornguyen]

What does this PR do?

S3FIFO, S3FIFOv0 and Clock2QPlus keep an object's read count in an int64_t (cacheObj.h), and every hit increments it without bound until the main FIFO passes the object again. The main-FIFO eviction loop copies the count into an int before testing freq >= 1:

int freq = obj_to_evict->S3FIFO.freq;

An object read 2^31 times since its last pass narrows to a negative value, so the loop takes the evict branch and removes the hottest object in the cache instead of reinserting it. The fix copies the count into an int64_t at all three sites. S4FIFO and SFIFO store an int32_t, so they do not narrow.

Type of change

• Bug fix

How was it tested?

The new /libCacheSim/cacheAlgo_S3FIFO_main_freq_beyond_int32 test fills a 100-object cache, promotes objects 1 to 10, and gives object 11, the oldest in the main FIFO, 2^31 reads. The next miss makes the main FIFO evict from its head. Object 11 must be reinserted and object 12 evicted.

Build	Result
develop + the test	fails: object 11 is evicted
this PR	passes: object 11 is kept with count 2, object 12 is evicted

Release build in ubuntu:24.04 with Ninja:

• ctest --test-dir _build --output-on-failure passes (10/10)
• Build is warning-free

Checklist

• Added or updated tests

[1a1a11a]

Thank you!