Move helper functions for optimizing division by constant into the APInt
class.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70488 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 4de6e35..6974dde 100644
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -2434,105 +2434,6 @@
return true;
}
-struct mu {
- APInt m; // magic number
- bool a; // add indicator
- unsigned s; // shift amount
-};
-
-/// magicu - calculate the magic numbers required to codegen an integer udiv as
-/// a sequence of multiply, add and shifts. Requires that the divisor not be 0.
-static mu magicu(const APInt& d) {
- unsigned p;
- APInt nc, delta, q1, r1, q2, r2;
- struct mu magu;
- magu.a = 0; // initialize "add" indicator
- APInt allOnes = APInt::getAllOnesValue(d.getBitWidth());
- APInt signedMin = APInt::getSignedMinValue(d.getBitWidth());
- APInt signedMax = APInt::getSignedMaxValue(d.getBitWidth());
-
- nc = allOnes - (-d).urem(d);
- p = d.getBitWidth() - 1; // initialize p
- q1 = signedMin.udiv(nc); // initialize q1 = 2p/nc
- r1 = signedMin - q1*nc; // initialize r1 = rem(2p,nc)
- q2 = signedMax.udiv(d); // initialize q2 = (2p-1)/d
- r2 = signedMax - q2*d; // initialize r2 = rem((2p-1),d)
- do {
- p = p + 1;
- if (r1.uge(nc - r1)) {
- q1 = q1 + q1 + 1; // update q1
- r1 = r1 + r1 - nc; // update r1
- }
- else {
- q1 = q1+q1; // update q1
- r1 = r1+r1; // update r1
- }
- if ((r2 + 1).uge(d - r2)) {
- if (q2.uge(signedMax)) magu.a = 1;
- q2 = q2+q2 + 1; // update q2
- r2 = r2+r2 + 1 - d; // update r2
- }
- else {
- if (q2.uge(signedMin)) magu.a = 1;
- q2 = q2+q2; // update q2
- r2 = r2+r2 + 1; // update r2
- }
- delta = d - 1 - r2;
- } while (p < d.getBitWidth()*2 &&
- (q1.ult(delta) || (q1 == delta && r1 == 0)));
- magu.m = q2 + 1; // resulting magic number
- magu.s = p - d.getBitWidth(); // resulting shift
- return magu;
-}
-
-// Magic for divide replacement
-struct ms {
- APInt m; // magic number
- unsigned s; // shift amount
-};
-
-/// magic - calculate the magic numbers required to codegen an integer sdiv as
-/// a sequence of multiply and shifts. Requires that the divisor not be 0, 1,
-/// or -1.
-static ms magic(const APInt& d) {
- unsigned p;
- APInt ad, anc, delta, q1, r1, q2, r2, t;
- APInt allOnes = APInt::getAllOnesValue(d.getBitWidth());
- APInt signedMin = APInt::getSignedMinValue(d.getBitWidth());
- APInt signedMax = APInt::getSignedMaxValue(d.getBitWidth());
- struct ms mag;
-
- ad = d.abs();
- t = signedMin + (d.lshr(d.getBitWidth() - 1));
- anc = t - 1 - t.urem(ad); // absolute value of nc
- p = d.getBitWidth() - 1; // initialize p
- q1 = signedMin.udiv(anc); // initialize q1 = 2p/abs(nc)
- r1 = signedMin - q1*anc; // initialize r1 = rem(2p,abs(nc))
- q2 = signedMin.udiv(ad); // initialize q2 = 2p/abs(d)
- r2 = signedMin - q2*ad; // initialize r2 = rem(2p,abs(d))
- do {
- p = p + 1;
- q1 = q1<<1; // update q1 = 2p/abs(nc)
- r1 = r1<<1; // update r1 = rem(2p/abs(nc))
- if (r1.uge(anc)) { // must be unsigned comparison
- q1 = q1 + 1;
- r1 = r1 - anc;
- }
- q2 = q2<<1; // update q2 = 2p/abs(d)
- r2 = r2<<1; // update r2 = rem(2p/abs(d))
- if (r2.uge(ad)) { // must be unsigned comparison
- q2 = q2 + 1;
- r2 = r2 - ad;
- }
- delta = ad - r2;
- } while (q1.ule(delta) || (q1 == delta && r1 == 0));
-
- mag.m = q2 + 1;
- if (d.isNegative()) mag.m = -mag.m; // resulting magic number
- mag.s = p - d.getBitWidth(); // resulting shift
- return mag;
-}
-
/// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant,
/// return a DAG expression to select that will generate the same value by
/// multiplying by a magic number. See:
@@ -2548,7 +2449,7 @@
return SDValue();
APInt d = cast<ConstantSDNode>(N->getOperand(1))->getAPIntValue();
- ms magics = magic(d);
+ APInt::ms magics = d.magic();
// Multiply the numerator (operand 0) by the magic value
// FIXME: We should support doing a MUL in a wider type
@@ -2607,7 +2508,7 @@
// FIXME: We should use a narrower constant when the upper
// bits are known to be zero.
ConstantSDNode *N1C = cast<ConstantSDNode>(N->getOperand(1));
- mu magics = magicu(N1C->getAPIntValue());
+ APInt::mu magics = N1C->getAPIntValue().magicu();
// Multiply the numerator (operand 0) by the magic value
// FIXME: We should support doing a MUL in a wider type