[SimplifyCFG] Swap to using TargetTransformInfo for cost

Description

[SimplifyCFG] Swap to using TargetTransformInfo for cost
analysis.

We're already using TTI in SimplifyCFG, so remove the hard-baked "cheapness"
heuristic and use TTI directly. Generally NFC intended, but we're using a slightly
different heuristic now so there is a slight test churn.

Test changes:

  • combine-comparisons-by-cse.ll: Removed unneeded branch check.
  • 2014-08-04-muls-it.ll: Test now doesn't branch but emits muleq.
  • coalesce-subregs.ll: Superfluous block check.
  • 2008-01-02-hoist-fp-add.ll: fadd is safe to speculate. Change to udiv.
  • PhiBlockMerge.ll: Superfluous CFG checking code. Main checks still present.
  • select-gep.ll: A variable GEP is not expensive, just TCC_Basic, according to the TTI.

Details

Committed
jamesmFeb 11 2015, 4:15 AM
Parents
rL228825: [mips] Merge disassemblers into a single implementation.
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