https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102108
Bug ID: 102108
Summary: [meta] ABI change due to SSE emulation of MMX
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Keywords: meta-bug
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: hjl.tools at gmail dot com
Depends on: 102027, 102105
Target Milestone: ---
Target: x86-64
There are calls to vector_mode_supported_p in stor-layout which changes the
TYPE_MODE of the RECORD_TYPE depending on if vector_mode_supported_p returns
true or not and classify_argument depends on TYPE_MODE in some cases.
Most back-ends moved away from looking at TYPE_MODE for argument passing long
time ago. I can understand why you might want to stay with that I don't think
anyone should depend on TYPE_MODE for argument passing any more.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102027
[Bug 102027] [11/12 Regression] ABI break when using vector type in function
arg/return value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102105
[Bug 102105] [10/11/12 Regression] x86_64: ABI break with vector in union and
-mno-mmx -mavx
