Simplify boolean expressions in Java AST (#10279)

Split from #10261 (see comments in that PR for discussion).

Fixes #10278

Author: zbynek

dev/core/src/com/google/gwt/dev/jjs/impl/Simplifier.java

@@ -429,8 +429,13 @@ public static JExpression simplifyAnd(JBinaryOperation expression) {
     if (rhs instanceof JBooleanLiteral) {
       if (((JBooleanLiteral) rhs).getValue()) {
         return lhs;
-      } else if (!lhs.hasSideEffects()) {
-        // Do not remove lhs if it had side effects
+      } else if (lhs.hasSideEffects()) {
+        // if side effect, rewrite a() && false to (a(), false)
+        // so that parent node can be simplified further
+        // e.g. (a() && false) && b() -> (a(), false) && b()
+        // -> (a(), false && b()) -> (a(), false)
+        return new JMultiExpression(info, lhs, rhs);
+      } else {
         return rhs;
       }
     }
@@ -482,7 +487,9 @@ public static JExpression simplifyOr(JBinaryOperation expression) {
     if (rhs instanceof JBooleanLiteral) {
       if (!((JBooleanLiteral) rhs).getValue()) {
         return lhs;
-      } else if (!lhs.hasSideEffects()) {
+      } else if (lhs.hasSideEffects()) {
+        return new JMultiExpression(info, lhs, rhs);
+      } else {
         return rhs;
       }
     }

dev/core/test/com/google/gwt/dev/jjs/impl/DeadCodeEliminationTest.java

@@ -298,6 +298,10 @@ public void testCommuteMultiExpression() throws Exception {
             + "static int f1;"
             + "static A createA() { A.f1 = 1; return new A(); } "
             + "static boolean booleanWithSideEffects() { createA(); return true;}"
+            + "@javaemul.internal.annotations.DoNotInline "
+            + "static boolean notInlinedBool1() { return true;}"
+            + "@javaemul.internal.annotations.DoNotInline "
+            + "static boolean notInlinedBool2() { return true;}"
             + "static boolean booleanWithoutSideEffects() { return true;}"
             + "static int arithmeticWithSideEffects() { createA(); return 4;}"
             + "}");
@@ -311,6 +315,28 @@ public void testCommuteMultiExpression() throws Exception {
     optimizeExpressions(false, "boolean", "false && A.booleanWithSideEffects()")
         .intoString("return false;");
 
+    optimizeExpressions(false, "boolean", "A.notInlinedBool1() && false")
+        .intoString("return (EntryPoint$A.notInlinedBool1(), false);");
+
+    optimizeExpressions(false, "int",
+        "A.notInlinedBool1() && (false && A.notInlinedBool2()) ? 1 : 2")
+        .intoString("return (EntryPoint$A.notInlinedBool1(), 2);");
+
+    optimizeExpressions(false, "int",
+        "(A.notInlinedBool1() && false) && A.notInlinedBool2() ? 1 : 2")
+        .intoString("return (EntryPoint$A.notInlinedBool1(), 2);");
+
+    optimizeExpressions(false, "boolean", "A.notInlinedBool1() || true")
+        .intoString("return (EntryPoint$A.notInlinedBool1(), true);");
+
+    optimizeExpressions(false, "int",
+        "A.notInlinedBool1() || (true || A.notInlinedBool2()) ? 1 : 2")
+        .intoString("return (EntryPoint$A.notInlinedBool1(), 1);");
+
+    optimizeExpressions(false, "int",
+        "(A.notInlinedBool1() || true) || A.notInlinedBool2() ? 1 : 2")
+        .intoString("return (EntryPoint$A.notInlinedBool1(), 1);");
+
     optimizeExpressions(false, "int", "3 + A.arithmeticWithSideEffects()")
         .intoString("return (EntryPoint$A.f1 = 1, new EntryPoint$A(), 7);");
   }