ART: Delete code optimizing a%1 and a%-1 from InstructionCodeGeneratorARM64

In InstructionWithAbsorbingInputSimplifier there is code optimizing a%1
and a%-1. So the code in InstructionCodeGeneratorARM64 optimizing such
cases can be deleted.

This patch deletes the code from InstructionCodeGeneratorARM64 and adds
additional tests.

Test: 012-math, 014-math3, 411-optimizing-arith, 411-checker-hdiv-hrem-pow2
Test: 701-easy-div-rem, 442-checker-constant-folding
Test: test-art-host, test-art-target
Change-Id: Ib80c0aa4c3e28b07fa79bb43783274c9d7fc456a

2 files changed, 6 insertions, 13 deletions

diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index d1c83ce625..02c995a833 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -5678,14 +5678,6 @@ void InstructionCodeGeneratorARM64::GenerateIntRemForPower2Denom(HRem *instructi
   }
 }
 
-void InstructionCodeGeneratorARM64::GenerateIntRemForOneOrMinusOneDenom(HRem *instruction) {
-  int64_t imm = Int64FromLocation(instruction->GetLocations()->InAt(1));
-  DCHECK(imm == 1 || imm == -1) << imm;
-
-  Register out = OutputRegister(instruction);
-  __ Mov(out, 0);
-}
-
 void InstructionCodeGeneratorARM64::GenerateIntRemForConstDenom(HRem *instruction) {
   int64_t imm = Int64FromLocation(instruction->GetLocations()->InAt(1));
 
@@ -5695,10 +5687,12 @@ void InstructionCodeGeneratorARM64::GenerateIntRemForConstDenom(HRem *instructio
     return;
   }
 
-  if (imm == 1 || imm == -1) {
-    // TODO: These cases need to be optimized in InstructionSimplifier
-    GenerateIntRemForOneOrMinusOneDenom(instruction);
-  } else if (IsPowerOfTwo(AbsOrMin(imm))) {
+  if (IsPowerOfTwo(AbsOrMin(imm))) {
+    // Cases imm == -1 or imm == 1 are handled in constant folding by
+    // InstructionWithAbsorbingInputSimplifier.
+    // If the cases have survided till code generation they are handled in
+    // GenerateIntRemForPower2Denom becauses -1 and 1 are the power of 2 (2^0).
+    // The correct code is generated for them, just more instructions.
     GenerateIntRemForPower2Denom(instruction);
   } else {
     DCHECK(imm < -2 || imm > 2) << imm;
diff --git a/compiler/optimizing/code_generator_arm64.h b/compiler/optimizing/code_generator_arm64.h
index c44fa48066..93bab3180c 100644
--- a/compiler/optimizing/code_generator_arm64.h
+++ b/compiler/optimizing/code_generator_arm64.h
@@ -327,7 +327,6 @@ class InstructionCodeGeneratorARM64 : public InstructionCodeGenerator {
   void GenerateIntDivForPower2Denom(HDiv *instruction);
   void GenerateIntRem(HRem* instruction);
   void GenerateIntRemForConstDenom(HRem *instruction);
-  void GenerateIntRemForOneOrMinusOneDenom(HRem *instruction);
   void GenerateIntRemForPower2Denom(HRem *instruction);
   void HandleGoto(HInstruction* got, HBasicBlock* successor);