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[X86] Use tcAdd/tcSubtract to implement the slow case of operator+=/operator-=.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299326 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Craig Topper
2017-04-02 06:59:43 +00:00
parent c3f2c54438
commit 8290bf9842
1 changed files with 3 additions and 33 deletions
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lib/Support/APInt.cpp
+3 -33
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@@ -226,21 +226,6 @@ APInt& APInt::operator--() {
return clearUnusedBits();
}
/// This function adds the integer array x to the integer array Y and
/// places the result in dest.
/// @returns the carry out from the addition
/// @brief General addition of 64-bit integer arrays
static bool add(uint64_t *dest, const uint64_t *x, const uint64_t *y,
unsigned len) {
bool carry = false;
for (unsigned i = 0; i< len; ++i) {
uint64_t limit = std::min(x[i],y[i]); // must come first in case dest == x
dest[i] = x[i] + y[i] + carry;
carry = dest[i] < limit || (carry && dest[i] == limit);
}
return carry;
}
/// Adds the RHS APint to this APInt.
/// @returns this, after addition of RHS.
/// @brief Addition assignment operator.
@@ -248,9 +233,8 @@ APInt& APInt::operator+=(const APInt& RHS) {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
if (isSingleWord())
VAL += RHS.VAL;
else {
add(pVal, pVal, RHS.pVal, getNumWords());
}
else
tcAdd(pVal, RHS.pVal, 0, getNumWords());
return clearUnusedBits();
}
@@ -262,20 +246,6 @@ APInt& APInt::operator+=(uint64_t RHS) {
return clearUnusedBits();
}
/// Subtracts the integer array y from the integer array x
/// @returns returns the borrow out.
/// @brief Generalized subtraction of 64-bit integer arrays.
static bool sub(uint64_t *dest, const uint64_t *x, const uint64_t *y,
unsigned len) {
bool borrow = false;
for (unsigned i = 0; i < len; ++i) {
uint64_t x_tmp = borrow ? x[i] - 1 : x[i];
borrow = y[i] > x_tmp || (borrow && x[i] == 0);
dest[i] = x_tmp - y[i];
}
return borrow;
}
/// Subtracts the RHS APInt from this APInt
/// @returns this, after subtraction
/// @brief Subtraction assignment operator.
@@ -284,7 +254,7 @@ APInt& APInt::operator-=(const APInt& RHS) {
if (isSingleWord())
VAL -= RHS.VAL;
else
sub(pVal, pVal, RHS.pVal, getNumWords());
tcSubtract(pVal, RHS.pVal, 0, getNumWords());
return clearUnusedBits();
}