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[Support] Move some APInt declarations in DivisionByConstantInfo to their first assignment.

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This uses copy initialization instead of default constructing the
APInts and assigning over them.
This commit is contained in:
Craig Topper 2022-12-22 21:50:01 -08:00
parent f112960190
commit 1a6310bf87
1 changed files with 16 additions and 18 deletions
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34
llvm/lib/Support/DivisionByConstantInfo.cpp
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@ -19,19 +19,18 @@ using namespace llvm;
/// the divisor not be 0, 1, or -1. Taken from "Hacker's Delight", Henry S.
/// Warren, Jr., Chapter 10.
SignedDivisionByConstantInfo SignedDivisionByConstantInfo::get(const APInt &D) {
unsigned P;
APInt AD, ANC, Delta, Q1, R1, Q2, R2, T;
APInt Delta;
APInt SignedMin = APInt::getSignedMinValue(D.getBitWidth());
struct SignedDivisionByConstantInfo Retval;
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))
APInt AD = D.abs();
APInt T = SignedMin + (D.lshr(D.getBitWidth() - 1));
APInt ANC = T - 1 - T.urem(AD); // absolute value of NC
unsigned P = D.getBitWidth() - 1; // initialize P
APInt Q1 = SignedMin.udiv(ANC); // initialize Q1 = 2P/abs(NC)
APInt R1 = SignedMin - Q1 * ANC; // initialize R1 = rem(2P,abs(NC))
APInt Q2 = SignedMin.udiv(AD); // initialize Q2 = 2P/abs(D)
APInt R2 = SignedMin - Q2 * AD; // initialize R2 = rem(2P,abs(D))
do {
P = P + 1;
Q1 = Q1 << 1; // update Q1 = 2P/abs(NC)
@ -64,20 +63,19 @@ SignedDivisionByConstantInfo SignedDivisionByConstantInfo::get(const APInt &D) {
/// of the divided value are known zero.
UnsignedDivisionByConstantInfo
UnsignedDivisionByConstantInfo::get(const APInt &D, unsigned LeadingZeros) {
unsigned P;
APInt NC, Delta, Q1, R1, Q2, R2;
APInt Delta;
struct UnsignedDivisionByConstantInfo Retval;
Retval.IsAdd = false; // initialize "add" indicator
APInt AllOnes = APInt::getAllOnes(D.getBitWidth()).lshr(LeadingZeros);
APInt SignedMin = APInt::getSignedMinValue(D.getBitWidth());
APInt SignedMax = APInt::getSignedMaxValue(D.getBitWidth());
NC = AllOnes - (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)
APInt NC = AllOnes - (AllOnes - D).urem(D);
unsigned P = D.getBitWidth() - 1; // initialize P
APInt Q1 = SignedMin.udiv(NC); // initialize Q1 = 2P/NC
APInt R1 = SignedMin - Q1 * NC; // initialize R1 = rem(2P,NC)
APInt Q2 = SignedMax.udiv(D); // initialize Q2 = (2P-1)/D
APInt R2 = SignedMax - Q2 * D; // initialize R2 = rem((2P-1),D)
do {
P = P + 1;
if (R1.uge(NC - R1)) {