[PATCH] D37899: [SystemZ] Implement shouldCoalesce() to help regalloc to avoid running out of registers with GR128 regs

[Ulrich Weigand via Phabricator via llvm-commits]

uweigand added a comment.

In https://reviews.llvm.org/D37899#875075, @jonpa wrote:

> Test cases updated. As expected, there are now more register moves whenever the coalescer is disabled by this patch.


Huh.  This seems more extreme than I expected, it looks like just about *every* load of a 128-bit value from memory now reloads into another set of registers, even in those quite simple test cases ...   Is this just the coalescing or is there something else going on?


https://reviews.llvm.org/D37899