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APInt: Unfold return expressions so RVO can work.

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Saves a couple of expensive deep copies. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219487 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer 2014-10-10 10:18:12 +00:00
parent 082e667c15
commit d8b0418d96
1 changed files with 28 additions and 10 deletions
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38
lib/Support/APInt.cpp
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@ -454,8 +454,10 @@ APInt APInt::XorSlowCase(const APInt& RHS) const {
for (unsigned i = 0; i < numWords; ++i)
val[i] = pVal[i] ^ RHS.pVal[i];
APInt Result(val, getBitWidth());
// 0^0==1 so clear the high bits in case they got set.
return APInt(val, getBitWidth()).clearUnusedBits();
Result.clearUnusedBits();
return Result;
}
APInt APInt::operator*(const APInt& RHS) const {
@ -473,7 +475,8 @@ APInt APInt::operator+(const APInt& RHS) const {
return APInt(BitWidth, VAL + RHS.VAL);
APInt Result(BitWidth, 0);
add(Result.pVal, this->pVal, RHS.pVal, getNumWords());
return Result.clearUnusedBits();
Result.clearUnusedBits();
return Result;
}
APInt APInt::operator-(const APInt& RHS) const {
@ -482,7 +485,8 @@ APInt APInt::operator-(const APInt& RHS) const {
return APInt(BitWidth, VAL - RHS.VAL);
APInt Result(BitWidth, 0);
sub(Result.pVal, this->pVal, RHS.pVal, getNumWords());
return Result.clearUnusedBits();
Result.clearUnusedBits();
return Result;
}
bool APInt::EqualSlowCase(const APInt& RHS) const {
@ -1114,7 +1118,9 @@ APInt APInt::ashr(unsigned shiftAmt) const {
uint64_t fillValue = (isNegative() ? -1ULL : 0);
for (unsigned i = breakWord+1; i < getNumWords(); ++i)
val[i] = fillValue;
return APInt(val, BitWidth).clearUnusedBits();
APInt Result(val, BitWidth);
Result.clearUnusedBits();
return Result;
}
/// Logical right-shift this APInt by shiftAmt.
@ -1151,7 +1157,9 @@ APInt APInt::lshr(unsigned shiftAmt) const {
// If we are shifting less than a word, compute the shift with a simple carry
if (shiftAmt < APINT_BITS_PER_WORD) {
lshrNear(val, pVal, getNumWords(), shiftAmt);
return APInt(val, BitWidth).clearUnusedBits();
APInt Result(val, BitWidth);
Result.clearUnusedBits();
return Result;
}
// Compute some values needed by the remaining shift algorithms
@ -1164,7 +1172,9 @@ APInt APInt::lshr(unsigned shiftAmt) const {
val[i] = pVal[i+offset];
for (unsigned i = getNumWords()-offset; i < getNumWords(); i++)
val[i] = 0;
return APInt(val,BitWidth).clearUnusedBits();
APInt Result(val, BitWidth);
Result.clearUnusedBits();
return Result;
}
// Shift the low order words
@ -1178,7 +1188,9 @@ APInt APInt::lshr(unsigned shiftAmt) const {
// Remaining words are 0
for (unsigned i = breakWord+1; i < getNumWords(); ++i)
val[i] = 0;
return APInt(val, BitWidth).clearUnusedBits();
APInt Result(val, BitWidth);
Result.clearUnusedBits();
return Result;
}
/// Left-shift this APInt by shiftAmt.
@ -1211,7 +1223,9 @@ APInt APInt::shlSlowCase(unsigned shiftAmt) const {
val[i] = pVal[i] << shiftAmt | carry;
carry = pVal[i] >> (APINT_BITS_PER_WORD - shiftAmt);
}
return APInt(val, BitWidth).clearUnusedBits();
APInt Result(val, BitWidth);
Result.clearUnusedBits();
return Result;
}
// Compute some values needed by the remaining shift algorithms
@ -1224,7 +1238,9 @@ APInt APInt::shlSlowCase(unsigned shiftAmt) const {
val[i] = 0;
for (unsigned i = offset; i < getNumWords(); i++)
val[i] = pVal[i-offset];
return APInt(val,BitWidth).clearUnusedBits();
APInt Result(val, BitWidth);
Result.clearUnusedBits();
return Result;
}
// Copy whole words from this to Result.
@ -1235,7 +1251,9 @@ APInt APInt::shlSlowCase(unsigned shiftAmt) const {
val[offset] = pVal[0] << wordShift;
for (i = 0; i < offset; ++i)
val[i] = 0;
return APInt(val, BitWidth).clearUnusedBits();
APInt Result(val, BitWidth);
Result.clearUnusedBits();
return Result;
}
APInt APInt::rotl(const APInt &rotateAmt) const {