Add a "loses information" return value to APFloat::convert

and APFloat::convertToInteger.  Restore return value to
IEEE754.  Adjust all users accordingly.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57329 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 23 insertions, 13 deletions

diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index 9256109..93ee7fe 100644
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -213,13 +213,14 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
   case Instruction::FPTrunc:
   case Instruction::FPExt:
     if (const ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
+      bool ignored;
       APFloat Val = FPC->getValueAPF();
       Val.convert(DestTy == Type::FloatTy ? APFloat::IEEEsingle :
                   DestTy == Type::DoubleTy ? APFloat::IEEEdouble :
                   DestTy == Type::X86_FP80Ty ? APFloat::x87DoubleExtended :
                   DestTy == Type::FP128Ty ? APFloat::IEEEquad :
                   APFloat::Bogus,
-                  APFloat::rmNearestTiesToEven);
+                  APFloat::rmNearestTiesToEven, &ignored);
       return ConstantFP::get(Val);
     }
     return 0; // Can't fold.
@@ -227,10 +228,11 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
   case Instruction::FPToSI:
     if (const ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
       const APFloat &V = FPC->getValueAPF();
+      bool ignored;
       uint64_t x[2]; 
       uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
       (void) V.convertToInteger(x, DestBitWidth, opc==Instruction::FPToSI,
-                                APFloat::rmTowardZero);
+                                APFloat::rmTowardZero, &ignored);
       APInt Val(DestBitWidth, 2, x);
       return ConstantInt::get(Val);
     }
diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 4471cfd..b0dd163 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -373,7 +373,8 @@ ConstantFP *ConstantFP::get(const APFloat &V) {
 /// 2.0/1.0 etc, that are known-valid both as double and as the target format.
 ConstantFP *ConstantFP::get(const Type *Ty, double V) {
   APFloat FV(V);
-  FV.convert(*TypeToFloatSemantics(Ty), APFloat::rmNearestTiesToEven);
+  bool ignored;
+  FV.convert(*TypeToFloatSemantics(Ty), APFloat::rmNearestTiesToEven, &ignored);
   return get(FV);
 }
 
@@ -955,20 +956,25 @@ bool ConstantInt::isValueValidForType(const Type *Ty, int64_t Val) {
 bool ConstantFP::isValueValidForType(const Type *Ty, const APFloat& Val) {
   // convert modifies in place, so make a copy.
   APFloat Val2 = APFloat(Val);
+  bool losesInfo;
   switch (Ty->getTypeID()) {
   default:
     return false;         // These can't be represented as floating point!
 
   // FIXME rounding mode needs to be more flexible
-  case Type::FloatTyID:
-    return &Val2.getSemantics() == &APFloat::IEEEsingle ||
-           Val2.convert(APFloat::IEEEsingle, APFloat::rmNearestTiesToEven) == 
-              APFloat::opOK;
-  case Type::DoubleTyID:
-    return &Val2.getSemantics() == &APFloat::IEEEsingle || 
-           &Val2.getSemantics() == &APFloat::IEEEdouble ||
-           Val2.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven) == 
-             APFloat::opOK;
+  case Type::FloatTyID: {
+    if (&Val2.getSemantics() == &APFloat::IEEEsingle)
+      return true;
+    Val2.convert(APFloat::IEEEsingle, APFloat::rmNearestTiesToEven, &losesInfo);
+    return !losesInfo;
+  }
+  case Type::DoubleTyID: {
+    if (&Val2.getSemantics() == &APFloat::IEEEsingle ||
+        &Val2.getSemantics() == &APFloat::IEEEdouble)
+      return true;
+    Val2.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, &losesInfo);
+    return !losesInfo;
+  }
   case Type::X86_FP80TyID:
     return &Val2.getSemantics() == &APFloat::IEEEsingle || 
            &Val2.getSemantics() == &APFloat::IEEEdouble ||
diff --git a/lib/VMCore/Core.cpp b/lib/VMCore/Core.cpp
index a802373..afc1c90 100644
--- a/lib/VMCore/Core.cpp
+++ b/lib/VMCore/Core.cpp
@@ -302,7 +302,9 @@ static const fltSemantics &SemanticsForType(Type *Ty) {
 
 LLVMValueRef LLVMConstReal(LLVMTypeRef RealTy, double N) {
   APFloat APN(N);
-  APN.convert(SemanticsForType(unwrap(RealTy)), APFloat::rmNearestTiesToEven);
+  bool ignored;
+  APN.convert(SemanticsForType(unwrap(RealTy)), APFloat::rmNearestTiesToEven,
+              &ignored);
   return wrap(ConstantFP::get(APN));
 }