x86 has
;; We use the Y prefix to denote any number of conditional register sets:
;; z First SSE register.
;; 2 SSE2 enabled
;; i SSE2 inter-unit moves enabled
;; m MMX inter-unit moves enabled
Most of them are internal to gcc. But some instructions use the fixed XMM0
register. We may need the Yz constraint for asm statement. Shouldn't it
be documented?
--
Summary: Undocumented Yz constraint
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: hjl dot tools at gmail dot com
GCC target triplet: x86-gnu-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38402
