This is another step towards ensuring that we produce the optimal code for reductions,
but there are other potential benefits as seen in the tests diffs:
1. Memory loads may get scalarized resulting in more efficient code.
2. Memory stores may get scalarized resulting in more efficient code.
3. Complex ops like fdiv/sqrt get scalarized which may be faster instructions depending on uarch.
4. Even simple ops like addss/subss/mulss/roundss may result in faster operation/less frequency throttling when scalarized depending on uarch.
The TODO comment suggests 1 or more follow-ups for opcodes that can currently result in regressions.
Differential Revision: https://reviews.llvm.org/D58282
llvm-svn: 355130
7fc6ef7dd7