[Bug tree-optimization/78821] GCC7: Copying whole 32 bits structure field by field not optimised into copying whole 32 bits at once

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78821

--- Comment #24 from Uroš Bizjak <ubizjak at gmail dot com> ---
Created attachment 42661
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42661&action=edit
Add bswaphi2 pattern

What do you think about going through bswaphi2 pattern, as in the attached
patch. Using of xcgh in place of bswap is suggested by Intel, but we can still
transform it to rotate in peephole2 pass.