From 8d9240df36bad759602ab4eda2be03a614fce2c0 Mon Sep 17 00:00:00 2001
From: Alexey Andreev <konsoletyper@gmail.com>
Date: Tue, 25 Apr 2017 22:57:35 +0300
Subject: [PATCH] When eliminating constant conditions, and removing dead
 branch, also remove corresponding phi input to avoid clashes with further
 optimizations

---
 .idea/runConfigurations/run_html4j_tests.xml  |  2 +-
 .../ConstantConditionElimination.java         | 22 +++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/.idea/runConfigurations/run_html4j_tests.xml b/.idea/runConfigurations/run_html4j_tests.xml
index 3a28f236d..aaabce13e 100644
--- a/.idea/runConfigurations/run_html4j_tests.xml
+++ b/.idea/runConfigurations/run_html4j_tests.xml
@@ -13,7 +13,7 @@
     <option name="MAIN_CLASS_NAME" value="" />
     <option name="METHOD_NAME" value="" />
     <option name="TEST_OBJECT" value="package" />
-    <option name="VM_PARAMETERS" value="-ea -Dteavm.junit.target=target/js-tests -Dteavm.junit.js.runner=htmlunit -Dteavm.junit.js.threads=1 -Dteavm.junit.minified=true -Dteavm.junit.optimized=true" />
+    <option name="VM_PARAMETERS" value="-ea -Dteavm.junit.target=target/js-tests -Dteavm.junit.js.threads=1 -Dteavm.junit.minified=true -Dteavm.junit.optimized=true" />
     <option name="PARAMETERS" value="" />
     <option name="WORKING_DIRECTORY" value="file://$MODULE_DIR$" />
     <option name="ENV_VARIABLES" />
diff --git a/core/src/main/java/org/teavm/model/optimization/ConstantConditionElimination.java b/core/src/main/java/org/teavm/model/optimization/ConstantConditionElimination.java
index d4159cb91..06af5173a 100644
--- a/core/src/main/java/org/teavm/model/optimization/ConstantConditionElimination.java
+++ b/core/src/main/java/org/teavm/model/optimization/ConstantConditionElimination.java
@@ -17,6 +17,7 @@ package org.teavm.model.optimization;
 
 import org.teavm.model.BasicBlock;
 import org.teavm.model.Instruction;
+import org.teavm.model.Phi;
 import org.teavm.model.Program;
 import org.teavm.model.instructions.BinaryBranchingCondition;
 import org.teavm.model.instructions.BinaryBranchingInstruction;
@@ -25,6 +26,7 @@ import org.teavm.model.instructions.BranchingInstruction;
 import org.teavm.model.instructions.IntegerConstantInstruction;
 import org.teavm.model.instructions.JumpInstruction;
 import org.teavm.model.instructions.NullConstantInstruction;
+import org.teavm.model.util.InstructionTransitionExtractor;
 
 public class ConstantConditionElimination implements MethodOptimization {
     private int[] constants;
@@ -53,19 +55,39 @@ public class ConstantConditionElimination implements MethodOptimization {
         }
 
         boolean changed = false;
+        InstructionTransitionExtractor transitionExtractor = new InstructionTransitionExtractor();
         for (int i = 0; i < program.basicBlockCount(); ++i) {
             BasicBlock block = program.basicBlockAt(i);
             Instruction insn = block.getLastInstruction();
             BasicBlock target = constantTarget(insn);
             if (target != null) {
+                block.getLastInstruction().acceptVisitor(transitionExtractor);
+
+                for (BasicBlock successor : transitionExtractor.getTargets()) {
+                    if (successor != target) {
+                        for (Phi phi : successor.getPhis()) {
+                            for (int j = 0; j < phi.getIncomings().size(); ++j) {
+                                if (phi.getIncomings().get(j).getSource() == block) {
+                                    phi.getIncomings().remove(j--);
+                                }
+                            }
+                        }
+                    }
+                }
+
                 JumpInstruction jump = new JumpInstruction();
                 jump.setTarget(target);
                 jump.setLocation(insn.getLocation());
                 block.getLastInstruction().replace(jump);
+
                 changed = true;
             }
         }
 
+        if (changed) {
+            new UnreachableBasicBlockEliminator().optimize(program);
+        }
+
         return changed;
     }