arc: Fix (u)maddhisi patterns
Rework the (u)maddhisi4 patterns and use VMAC2H(U) instruction instead
of the 64bit MAC(U) instruction.
This fixes the next execute.exp failures:
arith-rand-ll.c -O2 execution test
arith-rand-ll.c -O3 execution test
pr78726.c -O2 execution test
pr78726.c -O3 execution test
gcc/
2021-06-09 Claudiu Zissulescu <claziss@synopsys.com>
* config/arc/arc.md (maddhisi4): Use VMAC2H instruction.
(machi): New pattern.
(umaddhisi4): Use VMAC2HU instruction.
(umachi): New pattern.
Signed-off-by: Claudiu Zissulescu <claziss@synopsys.com>