Tim Northover 5a4800a05f ARM: override cost function to re-enable ConstantHoisting (& fix it).
At some point, ARM stopped getting any benefit from ConstantHoisting because
the pass called a different variant of getIntImmCost. Reimplementing the
correct variant revealed some problems, however:

  + ConstantHoisting was modifying switch statements. This is simply invalid,
    the cases must remain integer constants no matter the notional cost.
  + ConstantHoisting was mangling alloca instructions in the entry block. These
    should be handled by FrameLowering, so constants actually have a cost of 0.
    Worse, the resulting bitcasts meant they became dynamic allocas.

rdar://25707382

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266260 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-13 23:08:27 +00:00
..
2016-04-08 18:15:37 +00:00
2016-04-08 18:15:37 +00:00