[llvm] r297458 - [APInt] Add APInt::insertBits() method to insert an APInt into a larger APInt
Simon Pilgrim via llvm-commits
llvm-commits at lists.llvm.org
Fri Mar 10 05:44:33 PST 2017
Author: rksimon
Date: Fri Mar 10 07:44:32 2017
New Revision: 297458
URL: http://llvm.org/viewvc/llvm-project?rev=297458&view=rev
Log:
[APInt] Add APInt::insertBits() method to insert an APInt into a larger APInt
We currently have to insert bits via a temporary variable of the same size as the target with various shift/mask stages, resulting in further temporary variables, all of which require the allocation of memory for large APInts (MaskSizeInBits > 64).
This is another of the compile time issues identified in PR32037 (see also D30265).
This patch adds the APInt::insertBits() helper method which avoids the temporary memory allocation and masks/inserts the raw bits directly into the target.
Differential Revision: https://reviews.llvm.org/D30780
Modified:
llvm/trunk/include/llvm/ADT/APInt.h
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
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=297458&r1=297457&r2=297458&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/APInt.h (original)
+++ llvm/trunk/include/llvm/ADT/APInt.h Fri Mar 10 07:44:32 2017
@@ -1243,6 +1243,9 @@ public:
/// as "bitPosition".
void flipBit(unsigned bitPosition);
+ /// Insert the bits from a smaller APInt starting at bitPosition.
+ void insertBits(const APInt &SubBits, unsigned bitPosition);
+
/// Return an APInt with the extracted bits [bitPosition,bitPosition+numBits).
APInt extractBits(unsigned numBits, unsigned bitPosition) const;
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=297458&r1=297457&r2=297458&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Fri Mar 10 07:44:32 2017
@@ -7523,11 +7523,11 @@ bool BuildVectorSDNode::isConstantSplat(
if (OpVal.isUndef())
SplatUndef.setBits(BitPos, BitPos + EltBitSize);
else if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(OpVal))
- SplatValue |= CN->getAPIntValue().zextOrTrunc(EltBitSize).
- zextOrTrunc(sz) << BitPos;
+ SplatValue.insertBits(CN->getAPIntValue().zextOrTrunc(EltBitSize),
+ BitPos);
else if (ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(OpVal))
- SplatValue |= CN->getValueAPF().bitcastToAPInt().zextOrTrunc(sz) <<BitPos;
- else
+ SplatValue.insertBits(CN->getValueAPF().bitcastToAPInt(), BitPos);
+ else
return false;
}
Modified: llvm/trunk/lib/Support/APInt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/APInt.cpp?rev=297458&r1=297457&r2=297458&view=diff
==============================================================================
--- llvm/trunk/lib/Support/APInt.cpp (original)
+++ llvm/trunk/lib/Support/APInt.cpp Fri Mar 10 07:44:32 2017
@@ -588,6 +588,65 @@ void APInt::flipBit(unsigned bitPosition
else setBit(bitPosition);
}
+void APInt::insertBits(const APInt &subBits, unsigned bitPosition) {
+ unsigned subBitWidth = subBits.getBitWidth();
+ assert(0 < subBitWidth && (subBitWidth + bitPosition) <= BitWidth &&
+ "Illegal bit insertion");
+
+ // Insertion is a direct copy.
+ if (subBitWidth == BitWidth) {
+ *this = subBits;
+ return;
+ }
+
+ // Single word result can be done as a direct bitmask.
+ if (isSingleWord()) {
+ uint64_t mask = UINT64_MAX >> (APINT_BITS_PER_WORD - subBitWidth);
+ VAL &= ~(mask << bitPosition);
+ VAL |= (subBits.VAL << bitPosition);
+ return;
+ }
+
+ unsigned loBit = whichBit(bitPosition);
+ unsigned loWord = whichWord(bitPosition);
+ unsigned hi1Word = whichWord(bitPosition + subBitWidth - 1);
+
+ // Insertion within a single word can be done as a direct bitmask.
+ if (loWord == hi1Word) {
+ uint64_t mask = UINT64_MAX >> (APINT_BITS_PER_WORD - subBitWidth);
+ pVal[loWord] &= ~(mask << loBit);
+ pVal[loWord] |= (subBits.VAL << loBit);
+ return;
+ }
+
+ // Insert on word boundaries.
+ if (loBit == 0) {
+ // Direct copy whole words.
+ unsigned numWholeSubWords = subBitWidth / APINT_BITS_PER_WORD;
+ memcpy(pVal + loWord, subBits.getRawData(),
+ numWholeSubWords * APINT_WORD_SIZE);
+
+ // Mask+insert remaining bits.
+ unsigned remainingBits = subBitWidth % APINT_BITS_PER_WORD;
+ if (remainingBits != 0) {
+ uint64_t mask = UINT64_MAX >> (APINT_BITS_PER_WORD - remainingBits);
+ pVal[hi1Word] &= ~mask;
+ pVal[hi1Word] |= subBits.getWord(subBitWidth - 1);
+ }
+ return;
+ }
+
+ // General case - set/clear individual bits in dst based on src.
+ // TODO - there is scope for optimization here, but at the moment this code
+ // path is barely used so prefer readability over performance.
+ for (unsigned i = 0; i != subBitWidth; ++i) {
+ if (subBits[i])
+ setBit(bitPosition + i);
+ else
+ clearBit(bitPosition + i);
+ }
+}
+
APInt APInt::extractBits(unsigned numBits, unsigned bitPosition) const {
assert(numBits > 0 && "Can't extract zero bits");
assert(bitPosition < BitWidth && (numBits + bitPosition) <= BitWidth &&
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=297458&r1=297457&r2=297458&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Fri Mar 10 07:44:32 2017
@@ -5318,12 +5318,11 @@ static bool getTargetConstantBitsFromNod
return true;
}
if (auto *CInt = dyn_cast<ConstantInt>(Cst)) {
- Mask |= CInt->getValue().zextOrTrunc(SizeInBits).shl(BitOffset);
+ Mask.insertBits(CInt->getValue(), BitOffset);
return true;
}
if (auto *CFP = dyn_cast<ConstantFP>(Cst)) {
- APInt CstBits = CFP->getValueAPF().bitcastToAPInt();
- Mask |= CstBits.zextOrTrunc(SizeInBits).shl(BitOffset);
+ Mask.insertBits(CFP->getValueAPF().bitcastToAPInt(), BitOffset);
return true;
}
return false;
@@ -5340,7 +5339,7 @@ static bool getTargetConstantBitsFromNod
}
auto *Cst = cast<ConstantSDNode>(Src);
APInt Bits = Cst->getAPIntValue().zextOrTrunc(SrcEltSizeInBits);
- MaskBits |= Bits.zext(SizeInBits).shl(BitOffset);
+ MaskBits.insertBits(Bits, BitOffset);
}
return SplitBitData();
}
Modified: llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp?rev=297458&r1=297457&r2=297458&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp Fri Mar 10 07:44:32 2017
@@ -91,8 +91,7 @@ static bool extractConstantMask(const Co
continue;
}
- auto *Elt = cast<ConstantInt>(COp);
- MaskBits |= Elt->getValue().zextOrTrunc(CstSizeInBits).shl(BitOffset);
+ MaskBits.insertBits(cast<ConstantInt>(COp)->getValue(), BitOffset);
}
// Now extract the undef/constant bit data into the raw shuffle masks.
Modified: llvm/trunk/unittests/ADT/APIntTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/APIntTest.cpp?rev=297458&r1=297457&r2=297458&view=diff
==============================================================================
--- llvm/trunk/unittests/ADT/APIntTest.cpp (original)
+++ llvm/trunk/unittests/ADT/APIntTest.cpp Fri Mar 10 07:44:32 2017
@@ -1647,6 +1647,59 @@ TEST(APIntTest, reverseBits) {
}
}
+TEST(APIntTest, insertBits) {
+ APInt iSrc(31, 0x00123456);
+
+ // Direct copy.
+ APInt i31(31, 0x76543210ull);
+ i31.insertBits(iSrc, 0);
+ EXPECT_EQ(static_cast<int64_t>(0x00123456ull), i31.getSExtValue());
+
+ // Single word src/dst insertion.
+ APInt i63(63, 0x01234567FFFFFFFFull);
+ i63.insertBits(iSrc, 4);
+ EXPECT_EQ(static_cast<int64_t>(0x012345600123456Full), i63.getSExtValue());
+
+ // Insert single word src into one word of dst.
+ APInt i120(120, UINT64_MAX, true);
+ i120.insertBits(iSrc, 8);
+ EXPECT_EQ(static_cast<int64_t>(0xFFFFFF80123456FFull), i120.getSExtValue());
+
+ // Insert single word src into two words of dst.
+ APInt i127(127, UINT64_MAX, true);
+ i127.insertBits(iSrc, 48);
+ EXPECT_EQ(i127.extractBits(64, 0).getZExtValue(), 0x3456FFFFFFFFFFFF);
+ EXPECT_EQ(i127.extractBits(63, 64).getZExtValue(), 0x7FFFFFFFFFFF8012);
+
+ // Insert on word boundaries.
+ APInt i128(128, 0);
+ i128.insertBits(APInt(64, UINT64_MAX, true), 0);
+ i128.insertBits(APInt(64, UINT64_MAX, true), 64);
+ EXPECT_EQ(-1, i128.getSExtValue());
+
+ APInt i256(256, UINT64_MAX, true);
+ i256.insertBits(APInt(65, 0), 0);
+ i256.insertBits(APInt(69, 0), 64);
+ i256.insertBits(APInt(128, 0), 128);
+ EXPECT_EQ(0u, i256.getSExtValue());
+
+ APInt i257(257, 0);
+ i257.insertBits(APInt(96, UINT64_MAX, true), 64);
+ EXPECT_EQ(i257.extractBits(64, 0).getZExtValue(), 0x0000000000000000);
+ EXPECT_EQ(i257.extractBits(64, 64).getZExtValue(), 0xFFFFFFFFFFFFFFFF);
+ EXPECT_EQ(i257.extractBits(64, 128).getZExtValue(), 0x00000000FFFFFFFF);
+ EXPECT_EQ(i257.extractBits(65, 192).getZExtValue(), 0x0000000000000000);
+
+ // General insertion.
+ APInt i260(260, UINT64_MAX, true);
+ i260.insertBits(APInt(129, 1ull << 48), 15);
+ EXPECT_EQ(i260.extractBits(64, 0).getZExtValue(), 0x8000000000007FFF);
+ EXPECT_EQ(i260.extractBits(64, 64).getZExtValue(), 0x0000000000000000);
+ EXPECT_EQ(i260.extractBits(64, 128).getZExtValue(), 0xFFFFFFFFFFFF0000);
+ EXPECT_EQ(i260.extractBits(64, 192).getZExtValue(), 0xFFFFFFFFFFFFFFFF);
+ EXPECT_EQ(i260.extractBits(4, 256).getZExtValue(), 0x000000000000000F);
+}
+
TEST(APIntTest, extractBits) {
APInt i32(32, 0x1234567);
EXPECT_EQ(0x3456, i32.extractBits(16, 4));
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