Commit Graph

2 Commits

Author SHA1 Message Date
Guozhi Wei d2210af332 [MBP] Move a latch block with conditional exit and multi predecessors to top of loop
Current findBestLoopTop can find and move one kind of block to top, a latch block has one successor. Another common case is:

    * a latch block
    * it has two successors, one is loop header, another is exit
    * it has more than one predecessors

If it is below one of its predecessors P, only P can fall through to it, all other predecessors need a jump to it, and another conditional jump to loop header. If it is moved before loop header, all its predecessors jump to it, then fall through to loop header. So all its predecessors except P can reduce one taken branch.

Differential Revision: https://reviews.llvm.org/D43256

llvm-svn: 363471
2019-06-14 23:08:59 +00:00
David Green 4e3fd7757a [ARM] Add an extra constant hoisting test. NFC
This adds a simple extra test for constant hoisting to show it's
usefulness with constant addresses like those seen in memory
mapped registers in embedded systems.

llvm-svn: 358114
2019-04-10 18:05:57 +00:00