Unify simplification passes after high-level optimizations

* Add a constant folding pass after the later high-level optimizations
* Remove dead_code_elimination$after_lse to unify simplification passes (always constant folding, instruction simplifier, dead code elimination)
* Make dead_code_elimination$before_codegen run always.

Locally speed compile Pixel 5:
* system server -64.28KB (-0.13%)
* SystemUIGoogle: -16.31KB (-0.06%)
* AGSA: -140.57 (-0.04%)

Test: art/test/testrunner/testrunner.py --host --64 --optimizing -b
Change-Id: I305877fd83471dff059fe1d4f5b98e5b1063f1a5

2 files changed, 8 insertions, 9 deletions

diff --git a/compiler/optimizing/optimization.h b/compiler/optimizing/optimization.h
index c3ba17563e..2ef21b3ccc 100644
--- a/compiler/optimizing/optimization.h
+++ b/compiler/optimizing/optimization.h
@@ -43,7 +43,7 @@ class HOptimization : public ArenaObject<kArenaAllocOptimization> {
 
   // Return the name of the pass. Pass names for a single HOptimization should be of form
   // <optimization_name> or <optimization_name>$<pass_name> for common <optimization_name> prefix.
-  // Example: 'instruction_simplifier', 'instruction_simplifier$after_bce',
+  // Example: 'instruction_simplifier', 'instruction_simplifier$before_codegen',
   // 'instruction_simplifier$before_codegen'.
   const char* GetPassName() const { return pass_name_; }
 
diff --git a/compiler/optimizing/optimizing_compiler.cc b/compiler/optimizing/optimizing_compiler.cc
index db39ff98c3..60d5e6f3bd 100644
--- a/compiler/optimizing/optimizing_compiler.cc
+++ b/compiler/optimizing/optimizing_compiler.cc
@@ -671,18 +671,18 @@ void OptimizingCompiler::RunOptimizations(HGraph* graph,
     OptDef(OptimizationPass::kLoopOptimization),
     // Simplification.
     OptDef(OptimizationPass::kConstantFolding,
-           "constant_folding$after_bce"),
+           "constant_folding$after_loop_opt"),
     OptDef(OptimizationPass::kAggressiveInstructionSimplifier,
-           "instruction_simplifier$after_bce"),
+           "instruction_simplifier$after_loop_opt"),
     OptDef(OptimizationPass::kDeadCodeElimination,
-           "dead_code_elimination$after_bce"),
+           "dead_code_elimination$after_loop_opt"),
     // Other high-level optimizations.
     OptDef(OptimizationPass::kLoadStoreElimination),
-    OptDef(OptimizationPass::kDeadCodeElimination,
-           "dead_code_elimination$after_lse",
-           OptimizationPass::kLoadStoreElimination),
     OptDef(OptimizationPass::kCHAGuardOptimization),
     OptDef(OptimizationPass::kCodeSinking),
+    // Simplification.
+    OptDef(OptimizationPass::kConstantFolding,
+           "constant_folding$before_codegen"),
     // The codegen has a few assumptions that only the instruction simplifier
     // can satisfy. For example, the code generator does not expect to see a
     // HTypeConversion from a type to the same type.
@@ -691,8 +691,7 @@ void OptimizingCompiler::RunOptimizations(HGraph* graph,
     // Simplification may result in dead code that should be removed prior to
     // code generation.
     OptDef(OptimizationPass::kDeadCodeElimination,
-           "dead_code_elimination$before_codegen",
-           OptimizationPass::kAggressiveInstructionSimplifier),
+           "dead_code_elimination$before_codegen"),
     // Eliminate constructor fences after code sinking to avoid
     // complicated sinking logic to split a fence with many inputs.
     OptDef(OptimizationPass::kConstructorFenceRedundancyElimination)