One assignee leads the dataset with 1,825 of the 6,021 records in scope, well ahead of the fifth-place holder at 187. The top five assignees together account for 66.2% of all records, so the field is heavily concentrated rather than evenly spread across many filers. Anyone assessing freedom-to-operate in this space should expect most foundational claim territory to trace back to a small handful of companies, with a long tail of much smaller filers below them.

Filings rose from 275 in 2017 to a peak of 871 in 2022, then fell to 465 by 2024 — a 32% decline over that three-year span. That said, publication typically lags actual filing by around 18 months, so the lower counts seen in 2025 and 2026 in this dataset understate real activity rather than proving the field has cooled. The fairest read is that 2024 marks the most recent year with a reasonably complete picture, and it still shows a level well above the 2017 starting point.

General digital data processing (G06F) appears in 77.1% of the 6,021 records, which is expected given IR sits inside compiler and runtime infrastructure. Beyond that core, image data processing (G06T, 21.2%) and AI-model computing (G06N, 16.2%) are the two largest secondary classes, reflecting how much IR design work now targets graph-based and accelerator-oriented execution rather than purely scalar CPU code. Smaller shares in printed circuits, digital transmission, video recognition, display control and pictorial communication mark narrower application-specific filings.

The lower-share IPC classes — display control circuits at 1.5% and pictorial communication at 1.4% of the 6,021 records — point to areas where IR-specific claim density is thin relative to the core G06F territory. Debug-information preservation across lowering passes and invariant verification tailored to graph-form IR are two functionally important problems that show up far less often than core SSA-construction claims. These are reasonable areas to search in more depth before assuming they are unclaimed, but the raw class shares suggest less crowding than the top of the field.

US5999735A, filed by Intel and granted in 1999, claims a specific method for constructing a rank-n static single assignment intermediate language from a rank-(n-1) SSA form by finding a rank-1 definition that reaches a use and renaming both to a compiler temporary. Any freedom-to-operate assessment needs to check the patent's actual expiry and claim scope rather than assume it still controls all SSA construction — its citation count of 565 shows it has been influential as prior art, not that its claims remain broadly enforceable. Design-arounds typically avoid the exact rank-based renaming mechanism it describes while still achieving SSA form through alternative construction algorithms.