fix PR5978 by peeling the loop so that we avoid shifting the

result int by 8 for the first byte.  While normally harmless,
if the result is smaller than a byte, this shift is invalid.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93018 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index 194cabaf97..4ae8859a25 100644
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -398,8 +398,8 @@ static Constant *FoldReinterpretLoadFromConstPtr(Constant *C,
                           BytesLoaded, TD))
     return 0;
 
-  APInt ResultVal(IntType->getBitWidth(), 0);
-  for (unsigned i = 0; i != BytesLoaded; ++i) {
+  APInt ResultVal = APInt(IntType->getBitWidth(), RawBytes[BytesLoaded-1]);
+  for (unsigned i = 1; i != BytesLoaded; ++i) {
     ResultVal <<= 8;
     ResultVal |= APInt(IntType->getBitWidth(), RawBytes[BytesLoaded-1-i]);
   }