https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92190
--- Comment #9 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Liu Hao from comment #7)
> MSDN says 'the upper portions of YMM0-15 and ZMM0-15 are considered volatile
> and must be considered destroyed on function calls' explicitly [1].
BTW: MSDN is clear that xMM16-31 are volatile (call_used), so the current
definition of CALL_USER_REGISTERS is wrong. At least this part should be:
Index: i386.h
===================================================================
--- i386.h (revision 278455)
+++ i386.h (working copy)
@@ -1126,9 +1126,9 @@
/*xmm8,xmm9,xmm10,xmm11,xmm12,xmm13,xmm14,xmm15*/ \
6, 6, 6, 6, 6, 6, 6, 6, \
/*xmm16,xmm17,xmm18,xmm19,xmm20,xmm21,xmm22,xmm23*/ \
- 6, 6, 6, 6, 6, 6, 6, 6, \
+ 1, 1, 1, 1, 1, 1, 1, 1, \
/*xmm24,xmm25,xmm26,xmm27,xmm28,xmm29,xmm30,xmm31*/ \
- 6, 6, 6, 6, 6, 6, 6, 6, \
+ 1, 1, 1, 1, 1, 1, 1, 1, \
/* k0, k1, k2, k3, k4, k5, k6, k7*/ \
1, 1, 1, 1, 1, 1, 1, 1 }
