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Use the APFloat routines to evaluate FP immediates as 

integer constant expressions.  The only questionable
thing is that we now reject:

void foo() {
  switch (1) {
  case (int)1.0e10000:
    ;
  }
}

with:

t.c:5:13: error: case label does not reduce to an integer constant
  case (int)1.0e10000:
       ~~~~~^~~~~~~~~

GCC accepts this, emitting the pedwarn:
t.c:5: warning: floating constant exceeds range of 'double'

llvm-svn: 42238
This commit is contained in:
Chris Lattner 2007-09-22 19:04:13 +00:00
parent 9da7bc110a
commit 322abe3573
1 changed files with 26 additions and 11 deletions
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37
clang/AST/Expr.cpp
View File

@ -715,16 +715,16 @@ bool Expr::isIntegerConstantExpr(llvm::APSInt &Result, ASTContext &Ctx,
if (Loc) *Loc = SubExpr->getLocStart();
return false;
}
uint32_t DestWidth =
static_cast<uint32_t>(Ctx.getTypeSize(getType(), CastLoc));
// Handle simple integer->integer casts.
if (SubExpr->getType()->isIntegerType()) {
if (!SubExpr->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated))
return false;
// Figure out if this is a truncate, extend or noop cast.
unsigned DestWidth =
static_cast<uint32_t>(Ctx.getTypeSize(getType(), CastLoc));
// If the input is signed, do a sign extend, noop, or truncate.
if (SubExpr->getType()->isSignedIntegerType())
Result.sextOrTrunc(DestWidth);
@ -738,14 +738,29 @@ bool Expr::isIntegerConstantExpr(llvm::APSInt &Result, ASTContext &Ctx,
const Expr *Operand = SubExpr;
while (const ParenExpr *PE = dyn_cast<ParenExpr>(Operand))
Operand = PE->getSubExpr();
if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(Operand)) {
// FIXME: Evaluate this correctly!
Result = (int)FL->getValueAsDouble();
break;
// If this isn't a floating literal, we can't handle it.
const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(Operand);
if (!FL) {
if (Loc) *Loc = Operand->getLocStart();
return false;
}
if (Loc) *Loc = Operand->getLocStart();
return false;
// Determine whether we are converting to unsigned or signed.
bool DestSigned = getType()->isSignedIntegerType();
uint64_t Space[4];
llvm::APFloat::opStatus Status =
FL->getValue().convertToInteger(Space, DestWidth, DestSigned,
llvm::APFloat::rmNearestTiesToEven);
if (Status != llvm::APFloat::opOK && Status != llvm::APFloat::opInexact) {
if (Loc) *Loc = Operand->getLocStart();
return false; // FIXME: need to accept this as an extension.
}
Result = llvm::APInt(DestWidth, 4, Space);
break;
}
case ConditionalOperatorClass: {
const ConditionalOperator *Exp = cast<ConditionalOperator>(this);