Landing: 76dad9582058

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Project / Subsystem

gcc / arc

Date

2026-09-17

Author

Michiel Derhaeg

Commit

76dad9582058739e3e5f6d4db10c3c2e4de27a32

Source

github

Perf win

No

Breaking

No

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All attributes

project: gcc
subsystem: arc
patch_id: —
commit_hash: 76dad9582058739e3e5f6d4db10c3c2e4de27a32
source_type: github
headline: arc: Add missing condition code clobbers to prevent incorrect code
tldr: Fixed ARC target by declaring missing condition code clobbers in instruction patterns, resolving incorrect code generation.
author: Michiel Derhaeg
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • gcc
• arc
• target
• bugfix
• code-generation
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/76dad9582058739e3e5f6d4db10c3c2e4de27a32
date: 2026-09-17T00:00:00.000Z

This commit addresses an issue in the ARC target architecture where several instructions (doloop_end, loop_end, dbnz, flag, kflag) incorrectly modified condition codes without declaring this side effect. Due to a recent change moving AArch64 CC fusion into late-combine, GCC now keeps condition codes live across these instructions, leading to wrong code generation. By adding the necessary CC clobber declarations to the instruction patterns, GCC correctly accounts for these side effects, fixing bugs like PR68185 for ARC60x and ARC700.