Fix PR3468: a crash when constant folding a bitcast of

i80 to x86 long double (this was presumably generated
by sroa).

llvm-svn: 63730

llvm/lib/VMCore/ConstantFold.cpp

@@ -153,12 +153,11 @@ static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
       // Integral -> Integral. This is a no-op because the bit widths must
       // be the same. Consequently, we just fold to V.
       return V;
-    
-    if (DestTy->isFloatingPoint()) {
-      assert((DestTy == Type::DoubleTy || DestTy == Type::FloatTy) && 
-             "Unknown FP type!");
-      return ConstantFP::get(APFloat(CI->getValue()));
-    }
+
+    if (DestTy->isFloatingPoint())
+      return ConstantFP::get(APFloat(CI->getValue(),
+                                     DestTy != Type::PPC_FP128Ty));
+
     // Otherwise, can't fold this (vector?)
     return 0;
   }

llvm/test/Transforms/InstCombine/2009-02-04-FPBitcast.ll

@@ -0,0 +1,7 @@
+; RUN: llvm-as < %s | opt -instcombine
+; PR3468
+
+define x86_fp80 @cast() {
+	%tmp = bitcast i80 0 to x86_fp80		; <x86_fp80> [#uses=1]
+	ret x86_fp80 %tmp
+}