ART: Simplify HRem to reuse existing HDiv
A pattern seen in libcore and SPECjvm2008 workloads is a pair of HRem/HDiv
having the same dividend and divisor. The code generator processes
them separately and generates duplicated instructions calculating HDiv.
This CL adds detection of such a pattern to the instruction simplifier.
This optimization affects HInductionVarAnalysis and HLoopOptimization
preventing some loop optimizations. To avoid this the instruction simplifier
has the loop_friendly mode which means not to optimize HRems if they are in a loop.
A microbenchmark run on Pixel 3 shows the following improvements:
| little cores | big cores
arm32 Int32 | +21% | +40%
arm32 Int64 | +46% | +44%
arm64 Int32 | +27% | +14%
arm64 Int64 | +33% | +27%
Test: 411-checker-instruct-simplifier-hrem
Test: test.py --host --optimizing --jit --gtest --interpreter
Test: test.py --target --optimizing --jit --interpreter
Test: run-gtests.sh
Change-Id: I376a1bd299d7fe10acad46771236edd5f85dfe56
9 files changed
