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lib/CWriter/Writer.cpp: Copy AsmWriter's ConstantFP checking code here

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into a new function FPCSafeToPrint(), and use it in printConstant()
and printFunction() to decide whether we should output ConstantFPs as
floating-point constants or as references to stack-allocated variables.

lib/VMCore/AsmWriter.cpp: Fix an apparent typo in the code mentioned above.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6762 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Brian Gaeke 2003-06-17 23:55:35 +00:00
parent 4399a4982a
commit b471a23a85
3 changed files with 61 additions and 9 deletions
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34
lib/Target/CBackend/CBackend.cpp
View File

@ -360,6 +360,27 @@ void CWriter::printConstantArray(ConstantArray *CPA) {
}
}
/// FPCSafeToPrint - Returns true if we may assume that CFP may be
/// written out textually as a double (rather than as a reference to a
/// stack-allocated variable). We decide this by converting CFP to a
/// string and back into a double, and then checking whether the
/// conversion results in a bit-equal double to the original value of
/// CFP. This depends on us and the target C compiler agreeing on the
/// conversion process (which is pretty likely since we only deal in
/// IEEE FP.) This is adapted from similar code in
/// lib/VMCore/AsmWriter.cpp:WriteConstantInt().
static bool FPCSafeToPrint (const ConstantFP *CFP) {
std::string StrVal = ftostr(CFP->getValue());
// Check to make sure that the stringized number is not some string like
// "Inf" or NaN, that atof will accept, but the lexer will not. Check that
// the string matches the "[-+]?[0-9]" regex.
if ((StrVal[0] >= '0' && StrVal[0] <= '9') ||
((StrVal[0] == '-' || StrVal[0] == '+') &&
(StrVal[1] >= '0' && StrVal[1] <= '9')))
// Reparse stringized version!
return (atof(StrVal.c_str()) == CFP->getValue());
return false;
}
// printConstant - The LLVM Constant to C Constant converter.
void CWriter::printConstant(Constant *CPV) {
@ -435,7 +456,11 @@ void CWriter::printConstant(Constant *CPV) {
Out << "(*(" << (FPC->getType() == Type::FloatTy ? "float" : "double")
<< "*)&FloatConstant" << I->second << ")";
} else {
Out << FPC->getValue();
if (FPCSafeToPrint (FPC)) {
Out << ftostr (FPC->getValue ());
} else {
Out << FPC->getValue(); // Who knows? Give it our best shot...
}
}
break;
}
@ -795,7 +820,6 @@ void CWriter::printFunctionSignature(const Function *F, bool Prototype) {
}
void CWriter::printFunction(Function *F) {
if (F->isExternal()) return;
@ -826,12 +850,14 @@ void CWriter::printFunction(Function *F) {
// Scan the function for floating point constants. If any FP constant is used
// in the function, we want to redirect it here so that we do not depend on
// the precision of the printed form.
// the precision of the printed form, unless the printed form preserves
// precision.
//
unsigned FPCounter = 0;
for (constant_iterator I = constant_begin(F), E = constant_end(F); I != E;++I)
if (const ConstantFP *FPC = dyn_cast<ConstantFP>(*I))
if (FPConstantMap.find(FPC) == FPConstantMap.end()) {
if ((!FPCSafeToPrint(FPC)) // Do not put in FPConstantMap if safe.
&& (FPConstantMap.find(FPC) == FPConstantMap.end())) {
double Val = FPC->getValue();
FPConstantMap[FPC] = FPCounter; // Number the FP constants

34
lib/Target/CBackend/Writer.cpp
View File

@ -360,6 +360,27 @@ void CWriter::printConstantArray(ConstantArray *CPA) {
}
}
/// FPCSafeToPrint - Returns true if we may assume that CFP may be
/// written out textually as a double (rather than as a reference to a
/// stack-allocated variable). We decide this by converting CFP to a
/// string and back into a double, and then checking whether the
/// conversion results in a bit-equal double to the original value of
/// CFP. This depends on us and the target C compiler agreeing on the
/// conversion process (which is pretty likely since we only deal in
/// IEEE FP.) This is adapted from similar code in
/// lib/VMCore/AsmWriter.cpp:WriteConstantInt().
static bool FPCSafeToPrint (const ConstantFP *CFP) {
std::string StrVal = ftostr(CFP->getValue());
// Check to make sure that the stringized number is not some string like
// "Inf" or NaN, that atof will accept, but the lexer will not. Check that
// the string matches the "[-+]?[0-9]" regex.
if ((StrVal[0] >= '0' && StrVal[0] <= '9') ||
((StrVal[0] == '-' || StrVal[0] == '+') &&
(StrVal[1] >= '0' && StrVal[1] <= '9')))
// Reparse stringized version!
return (atof(StrVal.c_str()) == CFP->getValue());
return false;
}
// printConstant - The LLVM Constant to C Constant converter.
void CWriter::printConstant(Constant *CPV) {
@ -435,7 +456,11 @@ void CWriter::printConstant(Constant *CPV) {
Out << "(*(" << (FPC->getType() == Type::FloatTy ? "float" : "double")
<< "*)&FloatConstant" << I->second << ")";
} else {
Out << FPC->getValue();
if (FPCSafeToPrint (FPC)) {
Out << ftostr (FPC->getValue ());
} else {
Out << FPC->getValue(); // Who knows? Give it our best shot...
}
}
break;
}
@ -795,7 +820,6 @@ void CWriter::printFunctionSignature(const Function *F, bool Prototype) {
}
void CWriter::printFunction(Function *F) {
if (F->isExternal()) return;
@ -826,12 +850,14 @@ void CWriter::printFunction(Function *F) {
// Scan the function for floating point constants. If any FP constant is used
// in the function, we want to redirect it here so that we do not depend on
// the precision of the printed form.
// the precision of the printed form, unless the printed form preserves
// precision.
//
unsigned FPCounter = 0;
for (constant_iterator I = constant_begin(F), E = constant_end(F); I != E;++I)
if (const ConstantFP *FPC = dyn_cast<ConstantFP>(*I))
if (FPConstantMap.find(FPC) == FPConstantMap.end()) {
if ((!FPCSafeToPrint(FPC)) // Do not put in FPConstantMap if safe.
&& (FPConstantMap.find(FPC) == FPConstantMap.end())) {
double Val = FPC->getValue();
FPConstantMap[FPC] = FPCounter; // Number the FP constants

2
lib/VMCore/AsmWriter.cpp
View File

@ -234,7 +234,7 @@ static void WriteConstantInt(std::ostream &Out, const Constant *CV,
//
if ((StrVal[0] >= '0' && StrVal[0] <= '9') ||
((StrVal[0] == '-' || StrVal[0] == '+') &&
(StrVal[0] >= '0' && StrVal[0] <= '9')))
(StrVal[1] >= '0' && StrVal[1] <= '9')))
// Reparse stringized version!
if (atof(StrVal.c_str()) == CFP->getValue()) {
Out << StrVal; return;