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package org.graalvm.compiler.core.sparc;

import org.graalvm.compiler.core.common.type.IntegerStamp;
import org.graalvm.compiler.core.common.type.Stamp;
import org.graalvm.compiler.debug.GraalError;
import org.graalvm.compiler.graph.Node;
import org.graalvm.compiler.nodes.ConstantNode;
import org.graalvm.compiler.nodes.NodeView;
import org.graalvm.compiler.nodes.StructuredGraph;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.calc.CompareNode;
import org.graalvm.compiler.nodes.calc.SignExtendNode;
import org.graalvm.compiler.phases.Phase;

import jdk.vm.ci.code.CodeUtil;
import jdk.vm.ci.meta.JavaConstant;

SPARC only supports 32 and 64 bit integer compare. This phase turns CompareNodes which have IntegerStamp as input and its bit-width is not 32 or 64 bit into either a 32 or 64 bit compare by sign extending the input values. Why we do this in the HIR instead in the LIR? This enables the pattern matcher SPARCNodeMatchRules.signExtend(SignExtendNode, Access) to do it's job and replace loads with sign extending ones. /**
 * SPARC only supports 32 and 64 bit integer compare.
 *
 * This phase turns {@link CompareNode}s which have {@link IntegerStamp} as input and its bit-width
 * is not 32 or 64 bit into either a 32 or 64 bit compare by sign extending the input values.
 *
 * Why we do this in the HIR instead in the LIR? This enables the pattern matcher
 * {@link SPARCNodeMatchRules#signExtend(SignExtendNode, org.graalvm.compiler.nodes.memory.Access)}
 * to do it's job and replace loads with sign extending ones.
 */
public class SPARCIntegerCompareCanonicalizationPhase extends Phase {
    @Override
    protected void run(StructuredGraph graph) {
        for (Node n : graph.getNodes()) {
            if (n instanceof CompareNode) {
                CompareNode enode = (CompareNode) n;
                min32(enode, enode.getX());
                min32(enode, enode.getY());
            }
        }
    }

    private static void min32(CompareNode enode, ValueNode v) {
        Stamp s = v.stamp(NodeView.DEFAULT);
        if (s instanceof IntegerStamp) {
            int bits = ((IntegerStamp) s).getBits();
            if (bits != 32 && bits != 64) {
                if (bits <= 32) {
                    bits = 32;
                } else {
                    bits = 64;
                }
                ValueNode replacement;
                if (v instanceof ConstantNode) {
                    JavaConstant newConst;
                    if (bits == 32) {
                        newConst = JavaConstant.forInt(v.asJavaConstant().asInt());
                    } else if (bits == 64) {
                        newConst = JavaConstant.forLong(v.asJavaConstant().asLong());
                    } else {
                        throw GraalError.shouldNotReachHere();
                    }
                    long mask = CodeUtil.mask(bits);
                    replacement = v.graph().addOrUnique(new ConstantNode(newConst, IntegerStamp.stampForMask(bits, newConst.asLong() & mask, newConst.asLong() & mask)));
                } else {
                    replacement = v.graph().addOrUnique(new SignExtendNode(v, bits));
                }
                v.replaceAtUsages(replacement, x -> x == enode);
            }
        }
    }
}