Without these constraints asm() can't make use of mask registers.
gcc/
2019-06-27 Jan Beulich <jbeul...@suse.com>
* config/i386/constraints.md: Remove @internal from "k" and
"Yk".
--- a/gcc/config/i386/constraints.md
+++ b/gcc/config/i386/constraints.md
@@ -79,10 +79,10 @@
"Second from top of 80387 floating-point stack (@code{%st(1)}).")
(define_register_constraint "Yk" "TARGET_AVX512F ? MASK_REGS : NO_REGS"
-"@internal Any mask register that can be used as predicate, i.e. k1-k7.")
+"Any mask register that can be used as predicate, i.e. k1-k7.")
(define_register_constraint "k" "TARGET_AVX512F ? ALL_MASK_REGS : NO_REGS"
-"@internal Any mask register.")
+"Any mask register.")
;; Vector registers (also used for plain floating point nowadays).
(define_register_constraint "y" "TARGET_MMX ? MMX_REGS : NO_REGS"
