Landing: 57797c6404d8

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Project / Subsystem

gcc / gcc

Date

2026-05-03

Author

Jeff Law

Commit

57797c6404d81fdfa798c21b88ae6d8e19b23fd8

Source

github

Perf win

Yes

Breaking

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All attributes

project: gcc
subsystem: gcc
patch_id: —
commit_hash: 57797c6404d81fdfa798c21b88ae6d8e19b23fd8
source_type: github
headline: RISC-V: Improve Code Generation for Select Between 2^n and 0
tldr: GCC now generates more efficient RISC-V code for selecting between a power of 2 and zero, potentially saving bytes and improving performance.
author: Jeff Law
outcome: committed
performance_win: true
breaking_change: false
series_id: —
series_parts: []
tags: • risc-v
• code generation
• optimization
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/57797c6404d81fdfa798c21b88ae6d8e19b23fd8
date: 2026-05-03T00:00:00.000Z

GCC now generates more efficient RISC-V code for conditional expressions that select between a power of 2 (2^n) and 0. This optimization replaces a sequence of instructions with a shift-and-subtract, reducing code size and potentially improving performance by increasing the number of operations per fetch block. The change lays the groundwork for further generalizations to handle selecting between other constants.