https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122867
Bug ID: 122867
Summary: thumb cbz/cbnz patterns cannot handle large branch
ranges
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: rearnsha at gcc dot gnu.org
Target Milestone: ---
Created attachment 62919
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=62919&action=edit
testcase to demonstrate failure
The CBZ and CBNZ in thumb can fall back to a compare and conditional branch if
the range of CBZ is exceeded, but are unable to handle cases where a
conditional branch range is also exceeded; this sequence requires a conditional
branch around another non-conditional branch.
Not a regression since this has been the case since thumb2 support was first
added, but it does cause an assembly failure (for example the attached test
results in:
cc9K8P6I.s: Assembler messages:
cc9K8P6I.s:122: Error: conditional branch out of range
cc9K8P6I.s:147: Error: conditional branch out of range
cc9K8P6I.s:268: Error: conditional branch out of range
cc9K8P6I.s:293: Error: conditional branch out of range
