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[TableGen][CodeEmitter] Refactor addCodeToMergeInOperand (NFC) #158674

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Merged
merged 2 commits into from
Sep 16, 2025
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[TableGen][CodeEmitter] Refactor addCodeToMergeInOperand (NFC) #158674

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1007b93
[TableGen][CodeEmitter] Refactor addCodeToMergeInOperand (NFC)
s-barannikov Sep 15, 2025
de36c91
Update tests
s-barannikov Sep 15, 2025
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17 changes: 5 additions & 12 deletions llvm/test/TableGen/HwModeEncodeDecode3.td
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Original file line number Diff line number Diff line change
Expand Up @@ -230,28 +230,22 @@ def unrelated: Instruction {
// ENCODER: default: llvm_unreachable("Unhandled HwMode");
// ENCODER: case 0: {
// ENCODER: op = getMachineOpValue(MI, MI.getOperand(0), Fixups, STI);
// ENCODER: op &= UINT64_C(240);
// ENCODER: Value |= op;
// ENCODER: Value |= (op & 0xf0);
// ENCODER: break;
// ENCODER: }
// ENCODER: case 1: {
// ENCODER: op = getMachineOpValue(MI, MI.getOperand(0), Fixups, STI);
// ENCODER: op &= UINT64_C(240);
// ENCODER: Value |= op;
// ENCODER: Value |= (op & 0xf0);
// ENCODER: break;
// ENCODER: }
// ENCODER: case 2: {
// ENCODER: op = getMachineOpValue(MI, MI.getOperand(0), Fixups, STI);
// ENCODER: op &= UINT64_C(255);
// ENCODER: op <<= 8;
// ENCODER: Value |= op;
// ENCODER: Value |= (op & 0xff) << 8;
// ENCODER: break;
// ENCODER: }
// ENCODER: case 3: {
// ENCODER: op = getMachineOpValue(MI, MI.getOperand(0), Fixups, STI);
// ENCODER: op &= UINT64_C(255);
// ENCODER: op <<= 24;
// ENCODER: Value |= op;
// ENCODER: Value |= (op & 0xff) << 24;
// ENCODER: break;
// ENCODER: }
// ENCODER-LABEL: case ::baz: {
Expand All @@ -265,7 +259,6 @@ def unrelated: Instruction {
// ENCODER: default: llvm_unreachable("Unhandled HwMode");
// ENCODER: case 2: {
// ENCODER: op = getMachineOpValue(MI, MI.getOperand(0), Fixups, STI);
// ENCODER: op &= UINT64_C(240);
// ENCODER: Value |= op;
// ENCODER: Value |= (op & 0xf0);
// ENCODER: break;
// ENCODER: }
9 changes: 3 additions & 6 deletions llvm/test/TableGen/RegisterEncoder.td
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Expand Up @@ -30,8 +30,7 @@ def foo1 : Instruction {

// CHECK: case ::foo1: {
// CHECK: op = barEncoder
// CHECK: op &= UINT64_C(255);
// CHECK: Value |= op;
// CHECK: Value |= (op & 0xff);
// CHECK: break;
// CHECK: }

Expand All @@ -57,10 +56,8 @@ def foo2 : Instruction {

// CHECK: case ::foo2: {
// CHECK: op = barEncoder
// CHECK: op &= UINT64_C(15);
// CHECK: Value |= op;
// CHECK: Value |= (op & 0xf);
// CHECK: op = barEncoder
// CHECK: op &= UINT64_C(15);
// CHECK: Value |= op;
// CHECK: Value |= (op & 0xf) << 4;
// CHECK: break;
// CHECK: }
118 changes: 31 additions & 87 deletions llvm/utils/TableGen/CodeEmitterGen.cpp
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Expand Up @@ -31,6 +31,7 @@
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TableGen/Error.h"
Expand Down Expand Up @@ -139,58 +140,28 @@ bool CodeEmitterGen::addCodeToMergeInOperand(const Record *R,
StringRef EncoderMethodName =
CGI.Operands[SO.first].EncoderMethodNames[SO.second];

if (UseAPInt)
Case += " op.clearAllBits();\n";
raw_string_ostream OS(Case);
indent Indent(6);

OS << Indent << "// op: " << VarName << '\n';

Case += " // op: " + VarName + "\n";
if (UseAPInt)
OS << Indent << "op.clearAllBits();\n";

// If the source operand has a custom encoder, use it.
if (!EncoderMethodName.empty()) {
raw_string_ostream CaseOS(Case);
CaseOS << indent(6);
if (UseAPInt)
CaseOS << EncoderMethodName << "(MI, " << OpIdx << ", op";
OS << Indent << EncoderMethodName << "(MI, " << OpIdx
<< ", op, Fixups, STI);\n";
else
CaseOS << "op = " << EncoderMethodName << "(MI, " << OpIdx;
CaseOS << ", Fixups, STI);\n";
OS << Indent << "op = " << EncoderMethodName << "(MI, " << OpIdx
<< ", Fixups, STI);\n";
} else {
if (UseAPInt) {
Case +=
" getMachineOpValue(MI, MI.getOperand(" + utostr(OpIdx) + ")";
Case += ", op, Fixups, STI";
} else {
Case += " op = getMachineOpValue(MI, MI.getOperand(" +
utostr(OpIdx) + ")";
Case += ", Fixups, STI";
}
Case += ");\n";
}

// Precalculate the number of lits this variable contributes to in the
// operand. If there is a single lit (consecutive range of bits) we can use a
// destructive sequence on APInt that reduces memory allocations.
int NumOperandLits = 0;
for (int TmpBit = Bit; TmpBit >= 0;) {
int VarBit = getVariableBit(VarName, BI, TmpBit);

// If this bit isn't from a variable, skip it.
if (VarBit == -1) {
--TmpBit;
continue;
}

// Figure out the consecutive range of bits covered by this operand, in
// order to generate better encoding code.
int BeginVarBit = VarBit;
int N = 1;
for (--TmpBit; TmpBit >= 0;) {
VarBit = getVariableBit(VarName, BI, TmpBit);
if (VarBit == -1 || VarBit != (BeginVarBit - N))
break;
++N;
--TmpBit;
}
++NumOperandLits;
if (UseAPInt)
OS << Indent << "getMachineOpValue(MI, MI.getOperand(" << OpIdx
<< "), op, Fixups, STI);\n";
else
OS << Indent << "op = getMachineOpValue(MI, MI.getOperand(" << OpIdx
<< "), Fixups, STI);\n";
}

unsigned BitOffset = -1;
Expand All @@ -216,52 +187,25 @@ bool CodeEmitterGen::addCodeToMergeInOperand(const Record *R,
--Bit;
}

std::string MaskStr;
int OpShift;

unsigned LoBit = BeginVarBit - N + 1;
unsigned HiBit = LoBit + N;
unsigned LoInstBit = BeginInstBit - N + 1;
BitOffset = LoInstBit;
if (UseAPInt) {
std::string ExtractStr;
if (N >= 64) {
ExtractStr = "op.extractBits(" + itostr(HiBit - LoBit) + ", " +
itostr(LoBit) + ")";
Case += " Value.insertBits(" + ExtractStr + ", " +
itostr(LoInstBit) + ");\n";
} else {
ExtractStr = "op.extractBitsAsZExtValue(" + itostr(HiBit - LoBit) +
", " + itostr(LoBit) + ")";
Case += " Value.insertBits(" + ExtractStr + ", " +
itostr(LoInstBit) + ", " + itostr(HiBit - LoBit) + ");\n";
}
if (N > 64)
OS << Indent << "Value.insertBits(op.extractBits(" << N << ", " << LoBit
<< "), " << LoInstBit << ");\n";
else
OS << Indent << "Value.insertBits(op.extractBitsAsZExtValue(" << N
<< ", " << LoBit << "), " << LoInstBit << ", " << N << ");\n";
} else {
uint64_t OpMask = ~(uint64_t)0 >> (64 - N);
OpShift = BeginVarBit - N + 1;
OpMask <<= OpShift;
MaskStr = "UINT64_C(" + utostr(OpMask) + ")";
OpShift = BeginInstBit - BeginVarBit;

if (NumOperandLits == 1) {
Case += " op &= " + MaskStr + ";\n";
if (OpShift > 0) {
Case += " op <<= " + itostr(OpShift) + ";\n";
} else if (OpShift < 0) {
Case += " op >>= " + itostr(-OpShift) + ";\n";
}
Case += " Value |= op;\n";
} else {
if (OpShift > 0) {
Case += " Value |= (op & " + MaskStr + ") << " +
itostr(OpShift) + ";\n";
} else if (OpShift < 0) {
Case += " Value |= (op & " + MaskStr + ") >> " +
itostr(-OpShift) + ";\n";
} else {
Case += " Value |= (op & " + MaskStr + ");\n";
}
}
uint64_t OpMask = maskTrailingOnes<uint64_t>(N) << LoBit;
OS << Indent << "Value |= (op & " << format_hex(OpMask, 0) << ')';
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Q: If OpMask is > 32 bits, will the lack of UINT64_C cause issues (i.e, warning and/or the upper bits being lost?)

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I guess not, since op is uint64_t here, so it will get interpreted as a uint64_t.

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Right, the usual promotion rules apply, there should be no warnings or bit losses

int OpShift = BeginInstBit - BeginVarBit;
if (OpShift > 0)
OS << " << " << OpShift;
else if (OpShift < 0)
OS << " >> " << -OpShift;
OS << ";\n";
}
}

Expand Down