From 43421b3dd70af5b70e71816521f37502c397cc65 Mon Sep 17 00:00:00 2001
From: Dale Johannesen <dalej@apple.com>
Date: Thu, 6 Sep 2007 18:13:44 +0000
Subject: Next round of APFloat changes. Use APFloat in UpgradeParser and
 AsmParser. Change all references to ConstantFP to use the APFloat interface
 rather than double.  Remove the ConstantFP double interfaces. Use APFloat
 functions for constant folding arithmetic and comparisons. (There are still
 way too many places APFloat is just a wrapper around host float/double, but
 we're getting there.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41747 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/CBackend/CBackend.cpp | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

(limited to 'lib/Target/CBackend/CBackend.cpp')

diff --git a/lib/Target/CBackend/CBackend.cpp b/lib/Target/CBackend/CBackend.cpp
index b0c76c8..ff95e90 100644
--- a/lib/Target/CBackend/CBackend.cpp
+++ b/lib/Target/CBackend/CBackend.cpp
@@ -604,17 +604,19 @@ void CWriter::printConstantVector(ConstantVector *CP) {
 // only deal in IEEE FP).
 //
 static bool isFPCSafeToPrint(const ConstantFP *CFP) {
+  APFloat APF = APFloat(CFP->getValueAPF());  // copy
+  if (CFP->getType()==Type::FloatTy)
+    APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven);
 #if HAVE_PRINTF_A && ENABLE_CBE_PRINTF_A
   char Buffer[100];
-  sprintf(Buffer, "%a", CFP->getValue());
-
+  sprintf(Buffer, "%a", APF.convertToDouble());
   if (!strncmp(Buffer, "0x", 2) ||
       !strncmp(Buffer, "-0x", 3) ||
       !strncmp(Buffer, "+0x", 3))
-    return atof(Buffer) == CFP->getValue();
+    return APF.bitwiseIsEqual(APFloat(atof(Buffer)));
   return false;
 #else
-  std::string StrVal = ftostr(CFP->getValue());
+  std::string StrVal = ftostr(APF);
 
   while (StrVal[0] == ' ')
     StrVal.erase(StrVal.begin());
@@ -625,7 +627,7 @@ static bool isFPCSafeToPrint(const ConstantFP *CFP) {
       ((StrVal[0] == '-' || StrVal[0] == '+') &&
        (StrVal[1] >= '0' && StrVal[1] <= '9')))
     // Reparse stringized version!
-    return atof(StrVal.c_str()) == CFP->getValue();
+    return APF.bitwiseIsEqual(APFloat(atof(StrVal.c_str())));
   return false;
 #endif
 }
@@ -882,9 +884,13 @@ void CWriter::printConstant(Constant *CPV) {
       Out << "(*(" << (FPC->getType() == Type::FloatTy ? "float" : "double")
           << "*)&FPConstant" << I->second << ')';
     } else {
-      if (IsNAN(FPC->getValue())) {
+      double V = FPC->getType() == Type::FloatTy ? 
+                 FPC->getValueAPF().convertToFloat() : 
+                 FPC->getValueAPF().convertToDouble();
+      if (IsNAN(V)) {
         // The value is NaN
 
+        // FIXME the actual NaN bits should be emitted.
         // The prefix for a quiet NaN is 0x7FF8. For a signalling NaN,
         // it's 0x7ff4.
         const unsigned long QuietNaN = 0x7ff8UL;
@@ -893,7 +899,7 @@ void CWriter::printConstant(Constant *CPV) {
         // We need to grab the first part of the FP #
         char Buffer[100];
 
-        uint64_t ll = DoubleToBits(FPC->getValue());
+        uint64_t ll = DoubleToBits(V);
         sprintf(Buffer, "0x%llx", static_cast<long long>(ll));
 
         std::string Num(&Buffer[0], &Buffer[6]);
@@ -905,9 +911,9 @@ void CWriter::printConstant(Constant *CPV) {
         else
           Out << "LLVM_NAN" << (Val == QuietNaN ? "" : "S") << "(\""
               << Buffer << "\") /*nan*/ ";
-      } else if (IsInf(FPC->getValue())) {
+      } else if (IsInf(V)) {
         // The value is Inf
-        if (FPC->getValue() < 0) Out << '-';
+        if (V < 0) Out << '-';
         Out << "LLVM_INF" << (FPC->getType() == Type::FloatTy ? "F" : "")
             << " /*inf*/ ";
       } else {
@@ -915,12 +921,12 @@ void CWriter::printConstant(Constant *CPV) {
 #if HAVE_PRINTF_A && ENABLE_CBE_PRINTF_A
         // Print out the constant as a floating point number.
         char Buffer[100];
-        sprintf(Buffer, "%a", FPC->getValue());
+        sprintf(Buffer, "%a", V);
         Num = Buffer;
 #else
-        Num = ftostr(FPC->getValue());
+        Num = ftostr(FPC->getValueAPF());
 #endif
-        Out << Num;
+       Out << Num;
       }
     }
     break;
@@ -1715,15 +1721,15 @@ void CWriter::printFloatingPointConstants(Function &F) {
     if (const ConstantFP *FPC = dyn_cast<ConstantFP>(*I))
       if (!isFPCSafeToPrint(FPC) && // Do not put in FPConstantMap if safe.
           !FPConstantMap.count(FPC)) {
-        double Val = FPC->getValue();
-
         FPConstantMap[FPC] = FPCounter;  // Number the FP constants
 
         if (FPC->getType() == Type::DoubleTy) {
+          double Val = FPC->getValueAPF().convertToDouble();
           Out << "static const ConstantDoubleTy FPConstant" << FPCounter++
               << " = 0x" << std::hex << DoubleToBits(Val) << std::dec
               << "ULL;    /* " << Val << " */\n";
         } else if (FPC->getType() == Type::FloatTy) {
+          float Val = FPC->getValueAPF().convertToFloat();
           Out << "static const ConstantFloatTy FPConstant" << FPCounter++
               << " = 0x" << std::hex << FloatToBits(Val) << std::dec
               << "U;    /* " << Val << " */\n";
-- 
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