[Bug gas/29524] New: x86: move-with-sign-extend inconsistent with move-with-zero-extend

[jbeulich at suse dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29524

            Bug ID: 29524
           Summary: x86: move-with-sign-extend inconsistent with
                    move-with-zero-extend
           Product: binutils
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: gas
          Assignee: unassigned at sourceware dot org
          Reporter: jbeulich at suse dot com
  Target Milestone: ---

AT&T syntax, at least in its GNU interpretation, has always been permitting
sizing suffixes to be omitted when register operands allow proper sizing of an
insn. This principle is violated for move-with-sign-extend, as can be easily
seen with

        movsb   %al, %ax
        movsb   %al, %eax
        movsb   %al, %rax

        movsb   (%rax), %ax
        movsb   (%rax), %eax
        movsb   (%rax), %rax

        movzb   %al, %ax
        movzb   %al, %eax
        movzb   %al, %rax

        movzb   (%rax), %ax
        movzb   (%rax), %eax
        movzb   (%rax), %rax

        movsw   %ax, %eax
        movsw   %ax, %rax

        movsw   (%rax), %eax
        movsw   (%rax), %rax

        movzw   %ax, %eax
        movzw   %ax, %rax

        movzw   (%rax), %eax
        movzw   (%rax), %rax

        movsl   %eax, %rax

        movsl   (%rax), %rax

See the v1 posting of patches addressing this:
https://sourceware.org/pipermail/binutils/2022-August/122458.html
https://sourceware.org/pipermail/binutils/2022-August/122459.html

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