[Bug middle-end/78904] zero-extracts are not effective

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78904

--- Comment #5 from Uroš Bizjak <ubizjak at gmail dot com> ---
Created attachment 40405
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40405&action=edit
Prototype patch for addqi_ext_[1,2] patterns

The prototype patch compiles the testcase to:

        movl    %edi, %edx
        movl    %esi, %eax
        xorw    %di, %di
        addb    %dh, %ah
        movzwl  %ax, %eax
        orl     %edi, %eax