https://sourceware.org/bugzilla/show_bug.cgi?id=25438
--- Comment #7 from H.J. Lu <hjl.tools at gmail dot com> --- (In reply to Jan Beulich from comment #6) > (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. It is OK to encode "movzwq %ax,%rcx" as "movzwl %ax,%ecx". But assembler shouldn't accept "movzwl %ax,%rcx". -- You are receiving this mail because: You are on the CC list for the bug.
