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
diff --git a/compiler/optimizing/instruction_simplifier.h b/compiler/optimizing/instruction_simplifier.h
index 982a24a..feea771 100644
--- a/compiler/optimizing/instruction_simplifier.h
+++ b/compiler/optimizing/instruction_simplifier.h
@@ -40,9 +40,11 @@
InstructionSimplifier(HGraph* graph,
CodeGenerator* codegen,
OptimizingCompilerStats* stats = nullptr,
- const char* name = kInstructionSimplifierPassName)
+ const char* name = kInstructionSimplifierPassName,
+ bool use_all_optimizations = false)
: HOptimization(graph, name, stats),
- codegen_(codegen) {}
+ codegen_(codegen),
+ use_all_optimizations_(use_all_optimizations) {}
static constexpr const char* kInstructionSimplifierPassName = "instruction_simplifier";
@@ -51,6 +53,9 @@
private:
CodeGenerator* codegen_;
+ // Use all optimizations without restrictions.
+ bool use_all_optimizations_;
+
DISALLOW_COPY_AND_ASSIGN(InstructionSimplifier);
};