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[IR] Add a dedicated FNeg IR Instruction

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The IEEE-754 Standard makes it clear that fneg(x) and
fsub(-0.0, x) are two different operations. The former is a bitwise
operation, while the latter is an arithmetic operation. This patch
creates a dedicated FNeg IR Instruction to model that behavior.

Differential Revision: https://reviews.llvm.org/D53877

llvm-svn: 346774
This commit is contained in:
Cameron McInally
2018-11-13 18:15:47 +00:00
parent 9d87256d3d
commit cbde0d9c7b
30 changed files with 594 additions and 82 deletions
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47
llvm/lib/Bitcode/Reader/BitcodeReader.cpp
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@@ -964,6 +964,20 @@ static int getDecodedCastOpcode(unsigned Val) {
}
}
static int getDecodedUnaryOpcode(unsigned Val, Type *Ty) {
bool IsFP = Ty->isFPOrFPVectorTy();
// UnOps are only valid for int/fp or vector of int/fp types
if (!IsFP && !Ty->isIntOrIntVectorTy())
return -1;
switch (Val) {
default:
return -1;
case bitc::UNOP_NEG:
return IsFP ? Instruction::FNeg : -1;
}
}
static int getDecodedBinaryOpcode(unsigned Val, Type *Ty) {
bool IsFP = Ty->isFPOrFPVectorTy();
// BinOps are only valid for int/fp or vector of int/fp types
@@ -2317,6 +2331,19 @@ Error BitcodeReader::parseConstants() {
}
break;
}
case bitc::CST_CODE_CE_UNOP: { // CE_UNOP: [opcode, opval]
if (Record.size() < 2)
return error("Invalid record");
int Opc = getDecodedUnaryOpcode(Record[0], CurTy);
if (Opc < 0) {
V = UndefValue::get(CurTy); // Unknown unop.
} else {
Constant *LHS = ValueList.getConstantFwdRef(Record[1], CurTy);
unsigned Flags = 0;
V = ConstantExpr::get(Opc, LHS, Flags);
}
break;
}
case bitc::CST_CODE_CE_BINOP: { // CE_BINOP: [opcode, opval, opval]
if (Record.size() < 3)
return error("Invalid record");
@@ -3535,7 +3562,27 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
I = nullptr;
continue;
}
case bitc::FUNC_CODE_INST_UNOP: { // UNOP: [opval, ty, opcode]
unsigned OpNum = 0;
Value *LHS;
if (getValueTypePair(Record, OpNum, NextValueNo, LHS) ||
OpNum+1 > Record.size())
return error("Invalid record");
int Opc = getDecodedUnaryOpcode(Record[OpNum++], LHS->getType());
if (Opc == -1)
return error("Invalid record");
I = UnaryOperator::Create((Instruction::UnaryOps)Opc, LHS);
InstructionList.push_back(I);
if (OpNum < Record.size()) {
if (isa<FPMathOperator>(I)) {
FastMathFlags FMF = getDecodedFastMathFlags(Record[OpNum]);
if (FMF.any())
I->setFastMathFlags(FMF);
}
}
break;
}
case bitc::FUNC_CODE_INST_BINOP: { // BINOP: [opval, ty, opval, opcode]
unsigned OpNum = 0;
Value *LHS, *RHS;