Fix bug: test/Regression/Other/2002-04-07-HexFloatConstants.ll
llvm-svn: 2141
diff --git a/llvm/lib/VMCore/Constants.cpp b/llvm/lib/VMCore/Constants.cpp
index d9a2fa7..4102766 100644
--- a/llvm/lib/VMCore/Constants.cpp
+++ b/llvm/lib/VMCore/Constants.cpp
@@ -13,7 +13,6 @@
#include "llvm/Analysis/SlotCalculator.h"
#include "Support/StringExtras.h"
#include <algorithm>
-#include <assert.h>
using std::map;
using std::pair;
@@ -159,8 +158,27 @@
return utostr(Val.Unsigned);
}
+// ConstantFP::getStrValue - We would like to output the FP constant value in
+// exponential notation, but we cannot do this if doing so will lose precision.
+// Check here to make sure that we only output it in exponential format if we
+// can parse the value back and get the same value.
+//
std::string ConstantFP::getStrValue() const {
- return ftostr(Val);
+ std::string StrVal = ftostr(Val);
+ double TestVal = atof(StrVal.c_str()); // Reparse stringized version!
+ if (TestVal == Val)
+ return StrVal;
+
+ // Otherwise we could not reparse it to exactly the same value, so we must
+ // output the string in hexadecimal format!
+ //
+ // Behave nicely in the face of C TBAA rules... see:
+ // http://www.nullstone.com/htmls/category/aliastyp.htm
+ //
+ char *Ptr = (char*)&Val;
+ assert(sizeof(double) == sizeof(uint64_t) && sizeof(double) == 8 &&
+ "assuming that double is 64 bits!");
+ return "0x"+utohexstr(*(uint64_t*)Ptr);
}
std::string ConstantArray::getStrValue() const {