[llvm] r296147 - Revert: r296141 [APInt] Add APInt::extractBits() method to extract APInt subrange
Simon Pilgrim via llvm-commits
llvm-commits at lists.llvm.org
Fri Feb 24 10:31:05 PST 2017
Author: rksimon
Date: Fri Feb 24 12:31:04 2017
New Revision: 296147
URL: http://llvm.org/viewvc/llvm-project?rev=296147&view=rev
Log:
Revert: r296141 [APInt] Add APInt::extractBits() method to extract APInt subrange
The current pattern for extract bits in range is typically:
Mask.lshr(BitOffset).trunc(SubSizeInBits);
Which can be particularly slow for large APInts (MaskSizeInBits > 64) as they require the allocation of memory for the temporary variable.
This is another of the compile time issues identified in PR32037 (see also D30265).
This patch adds the APInt::extractBits() helper method which avoids the temporary memory allocation.
Differential Revision: https://reviews.llvm.org/D30336
Modified:
llvm/trunk/include/llvm/ADT/APInt.h
llvm/trunk/lib/Support/APInt.cpp
llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp
llvm/trunk/unittests/ADT/APIntTest.cpp
Modified: llvm/trunk/include/llvm/ADT/APInt.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/APInt.h?rev=296147&r1=296146&r2=296147&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/APInt.h (original)
+++ llvm/trunk/include/llvm/ADT/APInt.h Fri Feb 24 12:31:04 2017
@@ -1272,9 +1272,6 @@ public:
/// as "bitPosition".
void flipBit(unsigned bitPosition);
- /// Return an APInt with the extracted bits [bitPosition,bitPosition+numBits).
- APInt extractBits(unsigned numBits, unsigned bitPosition) const;
-
/// @}
/// \name Value Characterization Functions
/// @{
Modified: llvm/trunk/lib/Support/APInt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/APInt.cpp?rev=296147&r1=296146&r2=296147&view=diff
==============================================================================
--- llvm/trunk/lib/Support/APInt.cpp (original)
+++ llvm/trunk/lib/Support/APInt.cpp Fri Feb 24 12:31:04 2017
@@ -618,38 +618,6 @@ void APInt::flipBit(unsigned bitPosition
else setBit(bitPosition);
}
-APInt APInt::extractBits(unsigned numBits, unsigned bitPosition) const {
- assert(0 < numBits && "Can't extract zero bits");
- assert(bitPosition < BitWidth && (numBits + bitPosition) <= BitWidth &&
- "Illegal bit extraction");
-
- unsigned loBit = whichBit(bitPosition);
- if (isSingleWord())
- return APInt(numBits, VAL >> loBit);
-
- unsigned loWord = whichWord(bitPosition);
- unsigned hiWord = whichWord(bitPosition + numBits - 1);
-
- // Single word result extracting bits from a single word source.
- if (loWord == hiWord)
- return APInt(numBits, pVal[loWord] >> loBit);
-
- // Extracting bits that start on a source word boundary can be done
- // as a fast memory copy.
- if (loBit == 0)
- return APInt(numBits, makeArrayRef(pVal + loWord, 1 + hiWord - loWord));
-
- // General case - shift + copy source words into place.
- APInt Result(numBits, 0);
- uint64_t *pDst = Result.pVal;
- for (unsigned word = loWord; word < hiWord; ++word, ++pDst) {
- uint64_t w0 = pVal[word + 0];
- uint64_t w1 = pVal[word + 1];
- *pDst = (w0 >> loBit) | (w1 << (APINT_BITS_PER_WORD - loBit));
- }
- return Result.clearUnusedBits();
-}
-
unsigned APInt::getBitsNeeded(StringRef str, uint8_t radix) {
assert(!str.empty() && "Invalid string length");
assert((radix == 10 || radix == 8 || radix == 16 || radix == 2 ||
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=296147&r1=296146&r2=296147&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Fri Feb 24 12:31:04 2017
@@ -5207,8 +5207,8 @@ static bool getTargetConstantBitsFromNod
EltBits.resize(NumElts, APInt(EltSizeInBits, 0));
for (unsigned i = 0; i != NumElts; ++i) {
- unsigned BitOffset = i * EltSizeInBits;
- APInt UndefEltBits = UndefBits.extractBits(EltSizeInBits, BitOffset);
+ APInt UndefEltBits = UndefBits.lshr(i * EltSizeInBits);
+ UndefEltBits = UndefEltBits.zextOrTrunc(EltSizeInBits);
// Only treat an element as UNDEF if all bits are UNDEF.
if (UndefEltBits.isAllOnesValue()) {
@@ -5223,7 +5223,7 @@ static bool getTargetConstantBitsFromNod
if (UndefEltBits.getBoolValue() && !AllowPartialUndefs)
return false;
- APInt Bits = MaskBits.extractBits(EltSizeInBits, BitOffset);
+ APInt Bits = MaskBits.lshr(i * EltSizeInBits).zextOrTrunc(EltSizeInBits);
EltBits[i] = Bits.getZExtValue();
}
return true;
@@ -6421,7 +6421,7 @@ static Constant *getConstantVector(MVT V
SmallVector<Constant *, 32> ConstantVec;
for (unsigned i = 0; i < NumElm; i++) {
- APInt Val = SplatValue.extractBits(ScalarSize, ScalarSize * i);
+ APInt Val = SplatValue.lshr(ScalarSize * i).trunc(ScalarSize);
Constant *Const;
if (VT.isFloatingPoint()) {
assert((ScalarSize == 32 || ScalarSize == 64) &&
Modified: llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp?rev=296147&r1=296146&r2=296147&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp Fri Feb 24 12:31:04 2017
@@ -77,8 +77,8 @@ static bool extractConstantMask(const Co
RawMask.resize(NumMaskElts, 0);
for (unsigned i = 0; i != NumMaskElts; ++i) {
- unsigned BitOffset = i * MaskEltSizeInBits;
- APInt EltUndef = UndefBits.extractBits(MaskEltSizeInBits, BitOffset);
+ APInt EltUndef = UndefBits.lshr(i * MaskEltSizeInBits);
+ EltUndef = EltUndef.zextOrTrunc(MaskEltSizeInBits);
// Only treat the element as UNDEF if all bits are UNDEF, otherwise
// treat it as zero.
@@ -88,7 +88,8 @@ static bool extractConstantMask(const Co
continue;
}
- APInt EltBits = MaskBits.extractBits(MaskEltSizeInBits, BitOffset);
+ APInt EltBits = MaskBits.lshr(i * MaskEltSizeInBits);
+ EltBits = EltBits.zextOrTrunc(MaskEltSizeInBits);
RawMask[i] = EltBits.getZExtValue();
}
Modified: llvm/trunk/unittests/ADT/APIntTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/APIntTest.cpp?rev=296147&r1=296146&r2=296147&view=diff
==============================================================================
--- llvm/trunk/unittests/ADT/APIntTest.cpp (original)
+++ llvm/trunk/unittests/ADT/APIntTest.cpp Fri Feb 24 12:31:04 2017
@@ -1434,18 +1434,6 @@ TEST(APIntTest, isMask) {
}
}
-TEST(APIntTest, extractBits) {
- APInt i32(32, 0x1234567);
- EXPECT_EQ(0x3456, i32.extractBits(16, 4));
-
- APInt i256(256, -16776961 /* 0xFFFFFFFFFFFFFFFFFFFFFFFFFF0000FF */, true);
- EXPECT_EQ(255, i256.extractBits(16, 0));
- EXPECT_EQ(127, i256.extractBits(16, 1));
- EXPECT_EQ(-1, i256.extractBits(32, 64).getSExtValue());
- EXPECT_EQ(-1, i256.extractBits(128, 128).getSExtValue());
- EXPECT_EQ(-8388481, i256.extractBits(128, 1).getSExtValue());
-}
-
#if defined(__clang__)
// Disable the pragma warning from versions of Clang without -Wself-move
#pragma clang diagnostic push
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