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[oota-llvm.git] / lib / Support / ScaledNumber.cpp

diff --git a/lib/Support/ScaledNumber.cpp b/lib/Support/ScaledNumber.cpp
index 3fe027ba33164f156a3678ee242341e70ec0cb38..987c2d803b7e419c7f4821baedaad920ace35770 100644 (file)
--- a/lib/Support/ScaledNumber.cpp
+++ b/lib/Support/ScaledNumber.cpp
@@ -12,9 +12,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/ScaledNumber.h"
-
 #include "llvm/ADT/APFloat.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 using namespace llvm::ScaledNumbers;
@@ -169,6 +169,7 @@ static std::string toStringAPFloat(uint64_t D, int E, unsigned Precision) {
   int Shift = 63 - (NewE - E);
   assert(Shift <= LeadingZeros);
   assert(Shift == LeadingZeros || NewE == ScaledNumbers::MaxScale);
+  assert(Shift >= 0 && Shift < 64 && "undefined behavior");
   D <<= Shift;
   E = NewE;
 
@@ -220,6 +221,9 @@ std::string ScaledNumberBase::toString(uint64_t D, int16_t E, int Width,
   } else if (E > -64) {
     Above0 = D >> -E;
     Below0 = D << (64 + E);
+  } else if (E == -64) {
+    // Special case: shift by 64 bits is undefined behavior.
+    Below0 = D;
   } else if (E > -120) {
     Below0 = D >> (-E - 64);
     Extra = D << (128 + E);