March 2026: Delivered targeted compiler observability improvements to enhance debugging of instruction fusion in the XLA/TF backend. Implemented VLOG(2) debugging logs to surface fusion rejections, the exact reasons, and the producer/consumer instruction names involved in the ShouldFuse decision. Implementations were added in both repositories (Intel-tensorflow/tensorflow and openxla/xla) as described in PR #39413, with corresponding commits. These changes are logging-only and do not alter compilation semantics or runtime performance, preserving stability while enabling faster issue diagnosis. Validation included running existing unit tests (e.g., bazelisk test //xla/service:instruction_fusion_test) and manual log verification. Business value includes reduced debugging time for fusion-related regressions and improved reliability of fusion-based optimizations across backends.