RPCSX/llvm
1
0
Fork 0
mirror of https://github.com/RPCSX/llvm.git synced 2025-02-25 07:31:32 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

[APInt] Simplify the zext and sext methods

Browse Source 
This replaces a hand written copy loop with a call to memcpy for both zext and sext.

For sext, it replaces multiple if/else blocks propagating sign information forward. Now we just do a copy, a sign extension on the last copied word, a memset, and clearUnusedBits.

Differential Revision: https://reviews.llvm.org/D32417

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301201 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Craig Topper 2017-04-24 17:37:10 +00:00
parent e6dc33fc17
commit 36e5af50c1
1 changed files with 18 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

51
lib/Support/APInt.cpp
View File

@ -939,40 +939,26 @@ APInt APInt::trunc(unsigned width) const {
}
// Sign extend to a new width.
APInt APInt::sext(unsigned width) const {
assert(width > BitWidth && "Invalid APInt SignExtend request");
APInt APInt::sext(unsigned Width) const {
assert(Width > BitWidth && "Invalid APInt SignExtend request");
if (width <= APINT_BITS_PER_WORD)
return APInt(width, SignExtend64(VAL, BitWidth));
if (Width <= APINT_BITS_PER_WORD)
return APInt(Width, SignExtend64(VAL, BitWidth));
APInt Result(getMemory(getNumWords(width)), width);
APInt Result(getMemory(getNumWords(Width)), Width);
// Copy full words.
unsigned i;
uint64_t word = 0;
for (i = 0; i != BitWidth / APINT_BITS_PER_WORD; i++) {
word = getRawData()[i];
Result.pVal[i] = word;
}
// Copy words.
std::memcpy(Result.pVal, getRawData(), getNumWords() * APINT_WORD_SIZE);
// Read and sign-extend any partial word.
unsigned bits = (0 - BitWidth) % APINT_BITS_PER_WORD;
if (bits != 0)
word = (int64_t)getRawData()[i] << bits >> bits;
else
word = (int64_t)word >> (APINT_BITS_PER_WORD - 1);
// Write remaining full words.
for (; i != width / APINT_BITS_PER_WORD; i++) {
Result.pVal[i] = word;
word = (int64_t)word >> (APINT_BITS_PER_WORD - 1);
}
// Write any partial word.
bits = (0 - width) % APINT_BITS_PER_WORD;
if (bits != 0)
Result.pVal[i] = word << bits >> bits;
// Sign extend the last word since there may be unused bits in the input.
Result.pVal[getNumWords() - 1] =
SignExtend64(Result.pVal[getNumWords() - 1],
((BitWidth - 1) % APINT_BITS_PER_WORD) + 1);
// Fill with sign bits.
std::memset(Result.pVal + getNumWords(), isNegative() ? -1 : 0,
(Result.getNumWords() - getNumWords()) * APINT_WORD_SIZE);
Result.clearUnusedBits();
return Result;
}
@ -986,12 +972,11 @@ APInt APInt::zext(unsigned width) const {
APInt Result(getMemory(getNumWords(width)), width);
// Copy words.
unsigned i;
for (i = 0; i != getNumWords(); i++)
Result.pVal[i] = getRawData()[i];
std::memcpy(Result.pVal, getRawData(), getNumWords() * APINT_WORD_SIZE);
// Zero remaining words.
memset(&Result.pVal[i], 0, (Result.getNumWords() - i) * APINT_WORD_SIZE);
std::memset(Result.pVal + getNumWords(), 0,
(Result.getNumWords() - getNumWords()) * APINT_WORD_SIZE);
return Result;
}