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[ADT] Add implementations for avgFloor and avgCeil to APInt #84431

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Merged
merged 1 commit into from
Mar 14, 2024
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[ADT] Add implementations for avgFloor and avgCeil to APInt #84431

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12 changes: 12 additions & 0 deletions llvm/include/llvm/ADT/APInt.h
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Expand Up @@ -2193,6 +2193,18 @@ inline const APInt absdiff(const APInt &A, const APInt &B) {
return A.uge(B) ? (A - B) : (B - A);
}

/// Compute the floor of the signed average of C1 and C2
APInt avgFloorS(const APInt &C1, const APInt &C2);

/// Compute the floor of the unsigned average of C1 and C2
APInt avgFloorU(const APInt &C1, const APInt &C2);

/// Compute the ceil of the signed average of C1 and C2
APInt avgCeilS(const APInt &C1, const APInt &C2);

/// Compute the ceil of the unsigned average of C1 and C2
APInt avgCeilU(const APInt &C1, const APInt &C2);
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Does anyone have any preference for camelcase vs lowercase?

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Nope :)


/// Compute GCD of two unsigned APInt values.
///
/// This function returns the greatest common divisor of the two APInt values
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32 changes: 8 additions & 24 deletions llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
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Expand Up @@ -6021,30 +6021,14 @@ static std::optional<APInt> FoldValue(unsigned Opcode, const APInt &C1,
APInt C2Ext = C2.zext(FullWidth);
return (C1Ext * C2Ext).extractBits(C1.getBitWidth(), C1.getBitWidth());
}
case ISD::AVGFLOORS: {
unsigned FullWidth = C1.getBitWidth() + 1;
APInt C1Ext = C1.sext(FullWidth);
APInt C2Ext = C2.sext(FullWidth);
return (C1Ext + C2Ext).extractBits(C1.getBitWidth(), 1);
}
case ISD::AVGFLOORU: {
unsigned FullWidth = C1.getBitWidth() + 1;
APInt C1Ext = C1.zext(FullWidth);
APInt C2Ext = C2.zext(FullWidth);
return (C1Ext + C2Ext).extractBits(C1.getBitWidth(), 1);
}
case ISD::AVGCEILS: {
unsigned FullWidth = C1.getBitWidth() + 1;
APInt C1Ext = C1.sext(FullWidth);
APInt C2Ext = C2.sext(FullWidth);
return (C1Ext + C2Ext + 1).extractBits(C1.getBitWidth(), 1);
}
case ISD::AVGCEILU: {
unsigned FullWidth = C1.getBitWidth() + 1;
APInt C1Ext = C1.zext(FullWidth);
APInt C2Ext = C2.zext(FullWidth);
return (C1Ext + C2Ext + 1).extractBits(C1.getBitWidth(), 1);
}
case ISD::AVGFLOORS:
return APIntOps::avgFloorS(C1, C2);
case ISD::AVGFLOORU:
return APIntOps::avgFloorU(C1, C2);
case ISD::AVGCEILS:
return APIntOps::avgCeilS(C1, C2);
case ISD::AVGCEILU:
return APIntOps::avgCeilU(C1, C2);
case ISD::ABDS:
return APIntOps::smax(C1, C2) - APIntOps::smin(C1, C2);
case ISD::ABDU:
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36 changes: 36 additions & 0 deletions llvm/lib/Support/APInt.cpp
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Expand Up @@ -3094,3 +3094,39 @@ void llvm::LoadIntFromMemory(APInt &IntVal, const uint8_t *Src,
memcpy(Dst + sizeof(uint64_t) - LoadBytes, Src, LoadBytes);
}
}

APInt APIntOps::avgFloorS(const APInt &C1, const APInt &C2) {
// Return floor((C1 + C2)/2)
assert(C1.getBitWidth() == C2.getBitWidth() && "Unequal bitwidths");
unsigned FullWidth = C1.getBitWidth() + 1;
APInt C1Ext = C1.sext(FullWidth);
APInt C2Ext = C2.sext(FullWidth);
return (C1Ext + C2Ext).extractBits(C1.getBitWidth(), 1);
}

APInt APIntOps::avgFloorU(const APInt &C1, const APInt &C2) {
// Return floor((C1 + C2)/2)
assert(C1.getBitWidth() == C2.getBitWidth() && "Unequal bitwidths");
unsigned FullWidth = C1.getBitWidth() + 1;
APInt C1Ext = C1.zext(FullWidth);
APInt C2Ext = C2.zext(FullWidth);
return (C1Ext + C2Ext).extractBits(C1.getBitWidth(), 1);
}

APInt APIntOps::avgCeilS(const APInt &C1, const APInt &C2) {
// Return ceil((C1 + C2)/2)
assert(C1.getBitWidth() == C2.getBitWidth() && "Unequal bitwidths");
unsigned FullWidth = C1.getBitWidth() + 1;
APInt C1Ext = C1.sext(FullWidth);
APInt C2Ext = C2.sext(FullWidth);
return (C1Ext + C2Ext + 1).extractBits(C1.getBitWidth(), 1);
}

APInt APIntOps::avgCeilU(const APInt &C1, const APInt &C2) {
// Return ceil((C1 + C2)/2)
assert(C1.getBitWidth() == C2.getBitWidth() && "Unequal bitwidths");
unsigned FullWidth = C1.getBitWidth() + 1;
APInt C1Ext = C1.zext(FullWidth);
APInt C2Ext = C2.zext(FullWidth);
return (C1Ext + C2Ext + 1).extractBits(C1.getBitWidth(), 1);
}
86 changes: 86 additions & 0 deletions llvm/unittests/ADT/APIntTest.cpp
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Expand Up @@ -14,6 +14,7 @@
#include "llvm/Support/Alignment.h"
#include "gtest/gtest.h"
#include <array>
#include <climits>
#include <optional>

using namespace llvm;
Expand Down Expand Up @@ -2877,6 +2878,91 @@ TEST(APIntTest, RoundingSDiv) {
}
}

TEST(APIntTest, Average) {
APInt A0(32, 0);
APInt A2(32, 2);
APInt A100(32, 100);
APInt A101(32, 101);
APInt A200(32, 200, false);
APInt ApUMax(32, UINT_MAX, false);

EXPECT_EQ(APInt(32, 150), APIntOps::avgFloorU(A100, A200));
EXPECT_EQ(APIntOps::RoundingUDiv(A100 + A200, A2, APInt::Rounding::DOWN),
APIntOps::avgFloorU(A100, A200));
EXPECT_EQ(APIntOps::RoundingUDiv(A100 + A200, A2, APInt::Rounding::UP),
APIntOps::avgCeilU(A100, A200));
EXPECT_EQ(APIntOps::RoundingUDiv(A100 + A101, A2, APInt::Rounding::DOWN),
APIntOps::avgFloorU(A100, A101));
EXPECT_EQ(APIntOps::RoundingUDiv(A100 + A101, A2, APInt::Rounding::UP),
APIntOps::avgCeilU(A100, A101));
EXPECT_EQ(A0, APIntOps::avgFloorU(A0, A0));
EXPECT_EQ(A0, APIntOps::avgCeilU(A0, A0));
EXPECT_EQ(ApUMax, APIntOps::avgFloorU(ApUMax, ApUMax));
EXPECT_EQ(ApUMax, APIntOps::avgCeilU(ApUMax, ApUMax));
EXPECT_EQ(APIntOps::RoundingUDiv(ApUMax, A2, APInt::Rounding::DOWN),
APIntOps::avgFloorU(A0, ApUMax));
EXPECT_EQ(APIntOps::RoundingUDiv(ApUMax, A2, APInt::Rounding::UP),
APIntOps::avgCeilU(A0, ApUMax));

APInt Ap100(32, +100);
APInt Ap101(32, +101);
APInt Ap200(32, +200);
APInt Am1(32, -1);
APInt Am100(32, -100);
APInt Am101(32, -101);
APInt Am200(32, -200);
APInt AmSMin(32, INT_MIN);
APInt ApSMax(32, INT_MAX);

EXPECT_EQ(APInt(32, +150), APIntOps::avgFloorS(Ap100, Ap200));
EXPECT_EQ(APIntOps::RoundingSDiv(Ap100 + Ap200, A2, APInt::Rounding::DOWN),
APIntOps::avgFloorS(Ap100, Ap200));
EXPECT_EQ(APIntOps::RoundingSDiv(Ap100 + Ap200, A2, APInt::Rounding::UP),
APIntOps::avgCeilS(Ap100, Ap200));

EXPECT_EQ(APInt(32, -150), APIntOps::avgFloorS(Am100, Am200));
EXPECT_EQ(APIntOps::RoundingSDiv(Am100 + Am200, A2, APInt::Rounding::DOWN),
APIntOps::avgFloorS(Am100, Am200));
EXPECT_EQ(APIntOps::RoundingSDiv(Am100 + Am200, A2, APInt::Rounding::UP),
APIntOps::avgCeilS(Am100, Am200));

EXPECT_EQ(APInt(32, +100), APIntOps::avgFloorS(Ap100, Ap101));
EXPECT_EQ(APIntOps::RoundingSDiv(Ap100 + Ap101, A2, APInt::Rounding::DOWN),
APIntOps::avgFloorS(Ap100, Ap101));
EXPECT_EQ(APInt(32, +101), APIntOps::avgCeilS(Ap100, Ap101));
EXPECT_EQ(APIntOps::RoundingSDiv(Ap100 + Ap101, A2, APInt::Rounding::UP),
APIntOps::avgCeilS(Ap100, Ap101));

EXPECT_EQ(APInt(32, -101), APIntOps::avgFloorS(Am100, Am101));
EXPECT_EQ(APIntOps::RoundingSDiv(Am100 + Am101, A2, APInt::Rounding::DOWN),
APIntOps::avgFloorS(Am100, Am101));
EXPECT_EQ(APInt(32, -100), APIntOps::avgCeilS(Am100, Am101));
EXPECT_EQ(APIntOps::RoundingSDiv(Am100 + Am101, A2, APInt::Rounding::UP),
APIntOps::avgCeilS(Am100, Am101));

EXPECT_EQ(AmSMin, APIntOps::avgFloorS(AmSMin, AmSMin));
EXPECT_EQ(AmSMin, APIntOps::avgCeilS(AmSMin, AmSMin));

EXPECT_EQ(APIntOps::RoundingSDiv(AmSMin, A2, APInt::Rounding::DOWN),
APIntOps::avgFloorS(A0, AmSMin));
EXPECT_EQ(APIntOps::RoundingSDiv(AmSMin, A2, APInt::Rounding::UP),
APIntOps::avgCeilS(A0, AmSMin));

EXPECT_EQ(A0, APIntOps::avgFloorS(A0, A0));
EXPECT_EQ(A0, APIntOps::avgCeilS(A0, A0));

EXPECT_EQ(Am1, APIntOps::avgFloorS(AmSMin, ApSMax));
EXPECT_EQ(A0, APIntOps::avgCeilS(AmSMin, ApSMax));

EXPECT_EQ(APIntOps::RoundingSDiv(ApSMax, A2, APInt::Rounding::DOWN),
APIntOps::avgFloorS(A0, ApSMax));
EXPECT_EQ(APIntOps::RoundingSDiv(ApSMax, A2, APInt::Rounding::UP),
APIntOps::avgCeilS(A0, ApSMax));

EXPECT_EQ(ApSMax, APIntOps::avgFloorS(ApSMax, ApSMax));
EXPECT_EQ(ApSMax, APIntOps::avgCeilS(ApSMax, ApSMax));
}

TEST(APIntTest, umul_ov) {
const std::pair<uint64_t, uint64_t> Overflows[] = {
{0x8000000000000000, 2},
Expand Down