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Prepared for constant condition interval analysis

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This commit is contained in:
jespergravgaard 2019-08-29 08:54:38 +02:00
parent a064e766bc
commit 8ee1cf8b7e
1 changed files with 40 additions and 20 deletions
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60
src/main/java/dk/camelot64/kickc/passes/Pass2ConstantIfs.java
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@ -37,27 +37,8 @@ public class Pass2ConstantIfs extends Pass2SsaOptimization {
while(stmtIt.hasNext()) {
Statement statement = stmtIt.next();
if(statement instanceof StatementConditionalJump) {
ConstantLiteral literal = null;
StatementConditionalJump conditional = (StatementConditionalJump) statement;
ConstantValue constValue1 = Pass2ConstantIdentification.getConstant(conditional.getrValue1());
Operator operator = conditional.getOperator();
ConstantValue constValue2 = Pass2ConstantIdentification.getConstant(conditional.getrValue2());
try {
if(conditional.getrValue1() == null && operator == null && constValue2 != null) {
// Constant condition
literal = constValue2.calculateLiteral(getScope());
} else if(conditional.getrValue1() == null && operator != null && constValue2 != null) {
// Constant unary condition
ConstantValue constVal = Pass2ConstantIdentification.createUnary((OperatorUnary) operator, constValue2);
literal = constVal.calculateLiteral(getScope());
} else if(constValue1 != null && operator != null && constValue2 != null) {
// Constant binary condition
ConstantValue constVal = Pass2ConstantIdentification.createBinary(constValue1, (OperatorBinary) operator, constValue2, getScope());
literal = constVal.calculateLiteral(getScope());
}
} catch (ConstantNotLiteral e) {
// not literal - keep as null
}
ConstantLiteral literal = getConditionLiteralValue(conditional);
if(literal!=null && literal instanceof ConstantBool) {
// Condition is a constant boolean
if(((ConstantBool) literal).getBool()) {
@ -83,4 +64,43 @@ public class Pass2ConstantIfs extends Pass2SsaOptimization {
return modified;
}
/**
* If the condition always evaluates to constant true or false this finds tha value.
* @param conditional The conditional
* @return The literal value of the condition
*/
private ConstantLiteral getConditionLiteralValue(StatementConditionalJump conditional) {
ConstantValue constValue1 = Pass2ConstantIdentification.getConstant(conditional.getrValue1());
Operator operator = conditional.getOperator();
ConstantValue constValue2 = Pass2ConstantIdentification.getConstant(conditional.getrValue2());
try {
// If all values are constant find the literal condition value
if(conditional.getrValue1() == null && operator == null && constValue2 != null) {
// Constant condition
return constValue2.calculateLiteral(getScope());
} else if(conditional.getrValue1() == null && operator != null && constValue2 != null) {
// Constant unary condition
ConstantValue constVal = Pass2ConstantIdentification.createUnary((OperatorUnary) operator, constValue2);
return constVal.calculateLiteral(getScope());
} else if(constValue1 != null && operator != null && constValue2 != null) {
// Constant binary condition
ConstantValue constVal = Pass2ConstantIdentification.createBinary(constValue1, (OperatorBinary) operator, constValue2, getScope());
return constVal.calculateLiteral(getScope());
}
// Examine the intervals of the comparison parameters
// TODO: Compare intervals based on the operator
} catch (ConstantNotLiteral e) {
// not literal - keep as null
}
return null;
}
}