[Bug gas/25438] x86 MOVZ* anomalies for unusual/wrong operand combinations

[jbeulich at suse dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=25438

--- Comment #6 from Jan Beulich <jbeulich at suse dot com> ---
(In reply to H.J. Lu from comment #5)
> Also
> 
> [hjl@gnu-cfl-1 pr25438]$ cat y.s
> movzwl        %ax, %rcx
> [hjl@gnu-cfl-1 pr25438]$ gcc -c y.s
> [hjl@gnu-cfl-1 pr25438]$ objdump -dw y.o
> 
> y.o:     file format elf64-x86-64
> 
> 
> Disassembly of section .text:
> 
> 0000000000000000 <.text>:
>    0: 48 0f b7 c8             movzwq %ax,%rcx


And? How is this related here? This is an appropriate encoding for the insn.
When optimzing, dropping the REX prefix would seem desirable. In fact this is
already on my todo list.

-- 
You are receiving this mail because:
You are on the CC list for the bug.