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Simplify boolean expressions in Java AST #10279

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Merged
zbynek merged 2 commits into from
Apr 23, 2026
+36 −3
Merged

Simplify boolean expressions in Java AST #10279

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dbf7dec
Simplify boolean expressions in Java AST
zbynek Feb 20, 2026
54102dd
Add test cases, code style
zbynek Feb 24, 2026
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13 changes: 10 additions & 3 deletions dev/core/src/com/google/gwt/dev/jjs/impl/Simplifier.java
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
}
}
Expand Down Expand Up @@ -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;
}
}
Expand Down
26 changes: 26 additions & 0 deletions dev/core/test/com/google/gwt/dev/jjs/impl/DeadCodeEliminationTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -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;}"
+ "}");
Expand All @@ -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);");
}
Expand Down