Landing: 6d9758128603

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Project / Subsystem

gcc / ivopts

Date

2026-07-09

Author

Jovan Dmitrovic

Commit

6d97581286030449420dc4ee79612dd256067e2c

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: ivopts
patch_id: —
commit_hash: 6d97581286030449420dc4ee79612dd256067e2c
source_type: github
headline: ivopts: Zero register pressure cost when registers are abundant
tldr: Loop invariant optimization pass now reports zero register pressure cost if ample registers exist, avoiding unnecessary spilling.
author: Jovan Dmitrovic
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • optimization
• ivopts
• register allocation
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/6d97581286030449420dc4ee79612dd256067e2c
date: 2026-07-09T00:00:00.000Z

The ivopts_estimate_reg_pressure function within GCC’s loop invariant optimization pass now correctly returns zero when sufficient registers are available. This prevents the pass from incorrectly estimating high register pressure and potentially causing unnecessary register spilling, which occurs when the compiler believes it doesn’t have enough registers to hold all temporary values.