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RegAllocFast: Improve hinting heuristic

Authored by arsenm on May 16 2019, 5:50 AM.

Description

RegAllocFast: Improve hinting heuristic

Trace through multiple COPYs when looking for a physreg source. Add
hinting for vregs that will be copied into physregs (we only hinted
for vregs getting copied to a physreg previously). Give hinted a
register a bonus when deciding which value to spill. This is part of
my rewrite regallocfast series. In fact this one doesn't even have an
effect unless you also flip the allocation to happen from back to
front of a basic block. Nonetheless it helps to split this up to ease
review of D52010

Patch by Matthias Braun

llvm-svn: 360887

Details

Committed
arsenmMay 16 2019, 5:50 AM
Parents
rG3a0e6e1c6c96: [DominatorTree] Print roots unconditionally in `print()`.
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