Remove move param combiner optimization

- Jack generates only one move-param instruction by parameters, thus
this optimization is useless.

Change-Id: Ib2869ea9ed0a4cf99d0f2408d4962989835c2d9d

2 files changed, 1 insertions, 162 deletions

diff --git a/dx/src/com/android/jack/dx/ssa/MoveParamCombiner.java b/dx/src/com/android/jack/dx/ssa/MoveParamCombiner.java
deleted file mode 100644
index 29141f0..0000000
--- a/dx/src/com/android/jack/dx/ssa/MoveParamCombiner.java
+++ /dev/null
@@ -1,157 +0,0 @@
-/*
- * Copyright (C) 2008 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.jack.dx.ssa;
-
-import com.android.jack.dx.rop.code.CstInsn;
-import com.android.jack.dx.rop.code.LocalItem;
-import com.android.jack.dx.rop.code.RegOps;
-import com.android.jack.dx.rop.code.RegisterSpec;
-import com.android.jack.dx.rop.cst.CstInteger;
-
-import java.util.HashSet;
-import java.util.List;
-
-/**
- * Combine identical move-param insns, which may result from Ropper's
- * handling of synchronized methods.
- */
-public class MoveParamCombiner {
-
-  /** method to process */
-  private final SsaMethod ssaMeth;
-
-  /**
-   * Processes a method with this optimization step.
-   *
-   * @param ssaMethod method to process
-   */
-  public static void process(SsaMethod ssaMethod) {
-    new MoveParamCombiner(ssaMethod).run();
-  }
-
-  private MoveParamCombiner(SsaMethod ssaMeth) {
-    this.ssaMeth = ssaMeth;
-  }
-
-  /**
-   * Runs this optimization step.
-   */
-  private void run() {
-    // This will contain the definition specs for each parameter
-    final RegisterSpec[] paramSpecs = new RegisterSpec[ssaMeth.getParamWidth()];
-
-    // Insns to delete when all done
-    final HashSet<SsaInsn> deletedInsns = new HashSet<SsaInsn>();
-
-    ssaMeth.forEachInsn(new SsaInsn.Visitor() {
-      @Override
-      public void visitMoveInsn(NormalSsaInsn insn) {}
-
-      @Override
-      public void visitPhiInsn(PhiInsn phi) {}
-
-      @Override
-      public void visitNonMoveInsn(NormalSsaInsn insn) {
-        if (insn.getOpcode().getOpcode() != RegOps.MOVE_PARAM) {
-          return;
-        }
-
-        int param = getParamIndex(insn);
-
-        if (paramSpecs[param] == null) {
-          paramSpecs[param] = insn.getResult();
-        } else {
-          final RegisterSpec specA = paramSpecs[param];
-          final RegisterSpec specB = insn.getResult();
-          LocalItem localA = specA.getLocalItem();
-          LocalItem localB = specB.getLocalItem();
-          LocalItem newLocal;
-
-          /*
-           * Is there local information to preserve?
-           */
-
-if (localA == null) {
-            newLocal = localB;
-          } else if (localB == null) {
-            newLocal = localA;
-          } else if (localA.equals(localB)) {
-            newLocal = localA;
-          } else {
-            /*
-             * Oddly, these two identical move-params have distinct
-             * debug info. We'll just keep them distinct.
-             */
-            return;
-          }
-
-          ssaMeth.getDefinitionForRegister(specA.getReg()).setResultLocal(newLocal);
-
-          /*
-           * Map all uses of specB to specA
-           */
-
-          RegisterMapper mapper = new RegisterMapper() {
-            @Override
-            /** @inheritDoc */
-            public int getNewRegisterCount() {
-              return ssaMeth.getRegCount();
-            }
-
-            @Override
-            /** @inheritDoc */
-            public RegisterSpec map(RegisterSpec registerSpec) {
-              if (registerSpec.getReg() == specB.getReg()) {
-                return specA;
-              }
-
-              return registerSpec;
-            }
-          };
-
-          List<SsaInsn> uses = ssaMeth.getUseListForRegister(specB.getReg());
-
-          // Use list is modified by mapSourceRegisters
-          for (int i = uses.size() - 1; i >= 0; i--) {
-            SsaInsn use = uses.get(i);
-            use.mapSourceRegisters(mapper);
-          }
-
-          deletedInsns.add(insn);
-        }
-
-      }
-    });
-
-    ssaMeth.deleteInsns(deletedInsns);
-  }
-
-  /**
-   * Returns the parameter index associated with a move-param insn. Does
-   * not verify that the insn is a move-param insn.
-   *
-   * @param insn {@code non-null;} a move-param insn
-   * @return {@code >=0;} parameter index
-   */
-  private int getParamIndex(NormalSsaInsn insn) {
-    CstInsn cstInsn = (CstInsn) (insn.getOriginalRopInsn());
-
-    int param = ((CstInteger) cstInsn.getConstant()).getValue();
-    return param;
-  }
-
-}
diff --git a/dx/src/com/android/jack/dx/ssa/Optimizer.java b/dx/src/com/android/jack/dx/ssa/Optimizer.java
index 35d6460..42c6d28 100644
--- a/dx/src/com/android/jack/dx/ssa/Optimizer.java
+++ b/dx/src/com/android/jack/dx/ssa/Optimizer.java
@@ -34,7 +34,7 @@ public class Optimizer {
 
   /** optional optimizer steps */
   public enum OptionalStep {
-    MOVE_PARAM_COMBINER, SCCP, LITERAL_UPGRADE, CONST_COLLECTOR, ESCAPE_ANALYSIS
+    SCCP, LITERAL_UPGRADE, CONST_COLLECTOR, ESCAPE_ANALYSIS
   }
 
   /**
@@ -152,10 +152,6 @@ public class Optimizer {
   private static void runSsaFormSteps(SsaMethod ssaMeth, EnumSet<OptionalStep> steps) {
     boolean needsDeadCodeRemover = true;
 
-    if (steps.contains(OptionalStep.MOVE_PARAM_COMBINER)) {
-      MoveParamCombiner.process(ssaMeth);
-    }
-
     if (steps.contains(OptionalStep.SCCP)) {
       SCCP.process(ssaMeth);
       DeadCodeRemover.process(ssaMeth);