ARM: Merge data-processing instructions and shifts/(un)signed extensions

This commit mirrors the work that has already been done for ARM64.

Test: m test-art-target-run-test-551-checker-shifter-operand
Change-Id: Iec8c1563b035f40f0e18dcffde28d91dc21922f8

1 files changed, 32 insertions, 2 deletions

diff --git a/compiler/optimizing/instruction_simplifier_arm.h b/compiler/optimizing/instruction_simplifier_arm.h
index 9b54511340..e2ed257777 100644
--- a/compiler/optimizing/instruction_simplifier_arm.h
+++ b/compiler/optimizing/instruction_simplifier_arm.h
@@ -35,11 +35,41 @@ class InstructionSimplifierArmVisitor : public HGraphVisitor {
     }
   }
 
-  void VisitMul(HMul* instruction) OVERRIDE;
-  void VisitOr(HOr* instruction) OVERRIDE;
+  bool TryMergeIntoUsersShifterOperand(HInstruction* instruction);
+  bool TryMergeIntoShifterOperand(HInstruction* use, HInstruction* bitfield_op, bool do_merge);
+  bool CanMergeIntoShifterOperand(HInstruction* use, HInstruction* bitfield_op) {
+    return TryMergeIntoShifterOperand(use, bitfield_op, /* do_merge */ false);
+  }
+  bool MergeIntoShifterOperand(HInstruction* use, HInstruction* bitfield_op) {
+    DCHECK(CanMergeIntoShifterOperand(use, bitfield_op));
+    return TryMergeIntoShifterOperand(use, bitfield_op, /* do_merge */ true);
+  }
+
+  /**
+   * This simplifier uses a special-purpose BB visitor.
+   * (1) No need to visit Phi nodes.
+   * (2) Since statements can be removed in a "forward" fashion,
+   *     the visitor should test if each statement is still there.
+   */
+  void VisitBasicBlock(HBasicBlock* block) OVERRIDE {
+    // TODO: fragile iteration, provide more robust iterators?
+    for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
+      HInstruction* instruction = it.Current();
+      if (instruction->IsInBlock()) {
+        instruction->Accept(this);
+      }
+    }
+  }
+
   void VisitAnd(HAnd* instruction) OVERRIDE;
   void VisitArrayGet(HArrayGet* instruction) OVERRIDE;
   void VisitArraySet(HArraySet* instruction) OVERRIDE;
+  void VisitMul(HMul* instruction) OVERRIDE;
+  void VisitOr(HOr* instruction) OVERRIDE;
+  void VisitShl(HShl* instruction) OVERRIDE;
+  void VisitShr(HShr* instruction) OVERRIDE;
+  void VisitTypeConversion(HTypeConversion* instruction) OVERRIDE;
+  void VisitUShr(HUShr* instruction) OVERRIDE;
 
   OptimizingCompilerStats* stats_;
 };