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[ADT] Add signed and unsigned mulHi and mulLo to APInt
This addresses issue #84207
1 parent d9c8550 commit 1126436

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7 files changed

+84
-31
lines changed

7 files changed

+84
-31
lines changed

‎llvm/include/llvm/ADT/APInt.h

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2193,6 +2193,12 @@ inline const APInt absdiff(const APInt &A, const APInt &B) {
21932193
return A.uge(B) ? (A - B) : (B - A);
21942194
}
21952195

2196+
/// Return the high bits of the signed multiplication of C1 and C2.
2197+
APInt mulhs(const APInt &C1, const APInt &C2);
2198+
2199+
/// Return the high bits of the unsigned multiplication of C1 and C2.
2200+
APInt mulhu(const APInt &C1, const APInt &C2);
2201+
21962202
/// Compute GCD of two unsigned APInt values.
21972203
///
21982204
/// This function returns the greatest common divisor of the two APInt values

‎llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

Lines changed: 4 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -6009,18 +6009,10 @@ static std::optional<APInt> FoldValue(unsigned Opcode, const APInt &C1,
60096009
if (!C2.getBoolValue())
60106010
break;
60116011
return C1.srem(C2);
6012-
case ISD::MULHS: {
6013-
unsigned FullWidth = C1.getBitWidth() * 2;
6014-
APInt C1Ext = C1.sext(FullWidth);
6015-
APInt C2Ext = C2.sext(FullWidth);
6016-
return (C1Ext * C2Ext).extractBits(C1.getBitWidth(), C1.getBitWidth());
6017-
}
6018-
case ISD::MULHU: {
6019-
unsigned FullWidth = C1.getBitWidth() * 2;
6020-
APInt C1Ext = C1.zext(FullWidth);
6021-
APInt C2Ext = C2.zext(FullWidth);
6022-
return (C1Ext * C2Ext).extractBits(C1.getBitWidth(), C1.getBitWidth());
6023-
}
6012+
case ISD::MULHS:
6013+
return APIntOps::mulhs(C1, C2);
6014+
case ISD::MULHU:
6015+
return APIntOps::mulhu(C1, C2);
60246016
case ISD::AVGFLOORS: {
60256017
unsigned FullWidth = C1.getBitWidth() + 1;
60266018
APInt C1Ext = C1.sext(FullWidth);

‎llvm/lib/Support/APInt.cpp

Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3094,3 +3094,19 @@ void llvm::LoadIntFromMemory(APInt &IntVal, const uint8_t *Src,
30943094
memcpy(Dst + sizeof(uint64_t) - LoadBytes, Src, LoadBytes);
30953095
}
30963096
}
3097+
3098+
APInt APIntOps::mulhs(const APInt &C1, const APInt &C2) {
3099+
assert(C1.getBitWidth() == C2.getBitWidth());
3100+
unsigned FullWidth = C1.getBitWidth() * 2;
3101+
APInt C1Ext = C1.sext(FullWidth);
3102+
APInt C2Ext = C2.sext(FullWidth);
3103+
return (C1Ext * C2Ext).extractBits(C1.getBitWidth(), C1.getBitWidth());
3104+
}
3105+
3106+
APInt APIntOps::mulhu(const APInt &C1, const APInt &C2) {
3107+
assert(C1.getBitWidth() == C2.getBitWidth());
3108+
unsigned FullWidth = C1.getBitWidth() * 2;
3109+
APInt C1Ext = C1.zext(FullWidth);
3110+
APInt C2Ext = C2.zext(FullWidth);
3111+
return (C1Ext * C2Ext).extractBits(C1.getBitWidth(), C1.getBitWidth());
3112+
}

‎llvm/unittests/ADT/APIntTest.cpp

Lines changed: 52 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2805,6 +2805,58 @@ TEST(APIntTest, multiply) {
28052805
EXPECT_EQ(64U, i96.countr_zero());
28062806
}
28072807

2808+
TEST(APIntOpsTest, Mulh) {
2809+
2810+
// Unsigned
2811+
2812+
// 32 bits
2813+
APInt i32a(32, 0x0001'E235);
2814+
APInt i32b(32, 0xF623'55AD);
2815+
EXPECT_EQ(0x0001'CFA1, APIntOps::mulhu(i32a, i32b));
2816+
2817+
// 64 bits
2818+
APInt i64a(64, 0x1234'5678'90AB'CDEF);
2819+
APInt i64b(64, 0xFEDC'BA09'8765'4321);
2820+
EXPECT_EQ(0x121F'A000'A372'3A57, APIntOps::mulhu(i64a, i64b));
2821+
2822+
// 128 bits
2823+
APInt i128a(128, "1234567890ABCDEF1234567890ABCDEF", 16);
2824+
APInt i128b(128, "FEDCBA0987654321FEDCBA0987654321", 16);
2825+
APInt i128Res = APIntOps::mulhu(i128a, i128b);
2826+
EXPECT_EQ(APInt(128, "121FA000A3723A57E68984312C3A8D7E", 16), i128Res);
2827+
2828+
// Signed
2829+
2830+
// 32 bits
2831+
APInt i32c(32, 0x1234'5678); // +ve
2832+
APInt i32d(32, 0x10AB'CDEF); // +ve
2833+
APInt i32e(32, 0xFEDC'BA09); // -ve
2834+
2835+
EXPECT_EQ(0x012F'7D02, APIntOps::mulhs(i32c, i32d));
2836+
EXPECT_EQ(0xFFEB'4988, APIntOps::mulhs(i32c, i32e));
2837+
EXPECT_EQ(0x0001'4B68, APIntOps::mulhs(i32e, i32e));
2838+
2839+
// 64 bits
2840+
APInt i64c(64, 0x1234'5678'90AB'CDEF); // +ve
2841+
APInt i64d(64, 0x1234'5678'90FE'DCBA); // +ve
2842+
APInt i64e(64, 0xFEDC'BA09'8765'4321); // -ve
2843+
2844+
EXPECT_EQ(0x014B'66DC'328E'10C1, APIntOps::mulhs(i64c, i64d));
2845+
EXPECT_EQ(0xFFEB'4988'12C6'6C68, APIntOps::mulhs(i64c, i64e));
2846+
EXPECT_EQ(0x0001'4B68'2174'FA18, APIntOps::mulhs(i64e, i64e));
2847+
2848+
// 128 bits
2849+
APInt i128c(128, "1234567890ABCDEF1234567890ABCDEF", 16); // +ve
2850+
APInt i128d(128, "1234567890FEDCBA1234567890FEDCBA", 16); // +ve
2851+
APInt i128e(128, "FEDCBA0987654321FEDCBA0987654321", 16); // -ve
2852+
2853+
i128Res = APIntOps::mulhs(i128c, i128d);
2854+
EXPECT_EQ(APInt(128, "14B66DC328E10C1FE303DF9EA0B2529", 16), i128Res);
2855+
2856+
i128Res = APIntOps::mulhs(i128c, i128e);
2857+
EXPECT_EQ(APInt(128, "FFEB498812C66C68D4552DB89B8EBF8F", 16), i128Res);
2858+
}
2859+
28082860
TEST(APIntTest, RoundingUDiv) {
28092861
for (uint64_t Ai = 1; Ai <= 255; Ai++) {
28102862
APInt A(8, Ai);

‎llvm/unittests/Support/KnownBitsTest.cpp

Lines changed: 2 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -537,19 +537,13 @@ TEST(KnownBitsTest, BinaryExhaustive) {
537537
[](const KnownBits &Known1, const KnownBits &Known2) {
538538
return KnownBits::mulhs(Known1, Known2);
539539
},
540-
[](const APInt &N1, const APInt &N2) {
541-
unsigned Bits = N1.getBitWidth();
542-
return (N1.sext(2 * Bits) * N2.sext(2 * Bits)).extractBits(Bits, Bits);
543-
},
540+
[](const APInt &N1, const APInt &N2) { return APIntOps::mulhs(N1, N2); },
544541
checkCorrectnessOnlyBinary);
545542
testBinaryOpExhaustive(
546543
[](const KnownBits &Known1, const KnownBits &Known2) {
547544
return KnownBits::mulhu(Known1, Known2);
548545
},
549-
[](const APInt &N1, const APInt &N2) {
550-
unsigned Bits = N1.getBitWidth();
551-
return (N1.zext(2 * Bits) * N2.zext(2 * Bits)).extractBits(Bits, Bits);
552-
},
546+
[](const APInt &N1, const APInt &N2) { return APIntOps::mulhu(N1, N2); },
553547
checkCorrectnessOnlyBinary);
554548
}
555549

‎mlir/lib/Dialect/Arith/IR/ArithOps.cpp

Lines changed: 2 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -434,9 +434,7 @@ arith::MulSIExtendedOp::fold(FoldAdaptor adaptor,
434434
// Invoke the constant fold helper again to calculate the 'high' result.
435435
Attribute highAttr = constFoldBinaryOp<IntegerAttr>(
436436
adaptor.getOperands(), [](const APInt &a, const APInt &b) {
437-
unsigned bitWidth = a.getBitWidth();
438-
APInt fullProduct = a.sext(bitWidth * 2) * b.sext(bitWidth * 2);
439-
return fullProduct.extractBits(bitWidth, bitWidth);
437+
return llvm::APIntOps::mulhs(a, b);
440438
});
441439
assert(highAttr && "Unexpected constant-folding failure");
442440

@@ -491,9 +489,7 @@ arith::MulUIExtendedOp::fold(FoldAdaptor adaptor,
491489
// Invoke the constant fold helper again to calculate the 'high' result.
492490
Attribute highAttr = constFoldBinaryOp<IntegerAttr>(
493491
adaptor.getOperands(), [](const APInt &a, const APInt &b) {
494-
unsigned bitWidth = a.getBitWidth();
495-
APInt fullProduct = a.zext(bitWidth * 2) * b.zext(bitWidth * 2);
496-
return fullProduct.extractBits(bitWidth, bitWidth);
492+
return llvm::APIntOps::mulhu(a, b);
497493
});
498494
assert(highAttr && "Unexpected constant-folding failure");
499495

‎mlir/lib/Dialect/SPIRV/IR/SPIRVCanonicalization.cpp

Lines changed: 2 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -250,14 +250,11 @@ struct MulExtendedFold final : OpRewritePattern<MulOp> {
250250

251251
auto highBits = constFoldBinaryOp<IntegerAttr>(
252252
{lhsAttr, rhsAttr}, [](const APInt &a, const APInt &b) {
253-
unsigned bitWidth = a.getBitWidth();
254-
APInt c;
255253
if (IsSigned) {
256-
c = a.sext(bitWidth * 2) * b.sext(bitWidth * 2);
254+
return llvm::APIntOps::mulhs(a, b);
257255
} else {
258-
c = a.zext(bitWidth * 2) * b.zext(bitWidth * 2);
256+
return llvm::APIntOps::mulhu(a, b);
259257
}
260-
return c.extractBits(bitWidth, bitWidth); // Extract high result
261258
});
262259

263260
if (!highBits)

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