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

1 files changed, 8 insertions, 0 deletions

diff --git a/compiler/optimizing/optimization.cc b/compiler/optimizing/optimization.cc
index ec3b8c4904..424fbd9f45 100644
--- a/compiler/optimizing/optimization.cc
+++ b/compiler/optimizing/optimization.cc
@@ -83,6 +83,7 @@ const char* OptimizationPassName(OptimizationPass pass) {
       return HInliner::kInlinerPassName;
     case OptimizationPass::kSelectGenerator:
       return HSelectGenerator::kSelectGeneratorPassName;
+    case OptimizationPass::kAggressiveInstructionSimplifier:
     case OptimizationPass::kInstructionSimplifier:
       return InstructionSimplifier::kInstructionSimplifierPassName;
     case OptimizationPass::kCHAGuardOptimization:
@@ -248,6 +249,13 @@ ArenaVector<HOptimization*> ConstructOptimizations(
       case OptimizationPass::kInstructionSimplifier:
         opt = new (allocator) InstructionSimplifier(graph, codegen, stats, pass_name);
         break;
+      case OptimizationPass::kAggressiveInstructionSimplifier:
+        opt = new (allocator) InstructionSimplifier(graph,
+                                                    codegen,
+                                                    stats,
+                                                    pass_name,
+                                                    /* use_all_optimizations_ = */ true);
+        break;
       case OptimizationPass::kCHAGuardOptimization:
         opt = new (allocator) CHAGuardOptimization(graph, pass_name);
         break;