[llvm-commits] [llvm-gcc-4.2] r92108 - /llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp

[Dale Johannesen]

Author: johannes
Date: Wed Dec 23 19:08:32 2009
New Revision: 92108

URL: http://llvm.org/viewvc/llvm-project?rev=92108&view=rev
Log:
In some cases gcc builds a MODIFY_EXPR whose RHS
is smaller than its LHS.  Extend RHS in this case;
all the bits of LHS must be stored into, otherwise
they may be used uninitialized later.


Modified:
    llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp

Modified: llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp?rev=92108&r1=92107&r2=92108&view=diff

==============================================================================
--- llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp (original)
+++ llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp Wed Dec 23 19:08:32 2009
@@ -2939,9 +2939,13 @@
     if (ValTy->isSingleValueType()) {
       // Non-bitfield, scalar value.  Just emit a store.
       Value *RHS = Emit(rhs, 0);
-      // Convert RHS to the right type if we can, otherwise convert the pointer.
+      // Convert RHS to the right type if we can.  If LHS is bigger than RHS
+      // we must convert; all the bits of LHS must be stored into.  Otherwise
+      // convert the pointer.
       const PointerType *PT = cast<PointerType>(LV.Ptr->getType());
-      if (PT->getElementType()->canLosslesslyBitCastTo(RHS->getType()))
+      if (PT->getElementType()->canLosslesslyBitCastTo(RHS->getType()) ||
+          (PT->getElementType()->getPrimitiveSizeInBits() >
+           RHS->getType()->getPrimitiveSizeInBits()))
         RHS = CastToAnyType(RHS, RHSSigned, PT->getElementType(), LHSSigned);
       else
         LV.Ptr = BitCastToType(LV.Ptr, RHS->getType()->getPointerTo());