fix PR6332, allowing an index of zero into a zero sized array

even if the element of the array has no size.

llvm-svn: 101662

2 files changed, 10 insertions, 2 deletions

diff --git a/llvm/lib/Target/TargetData.cpp b/llvm/lib/Target/TargetData.cpp
index abee2e19244..d89fafd8137 100644
--- a/llvm/lib/Target/TargetData.cpp
+++ b/llvm/lib/Target/TargetData.cpp
@@ -630,8 +630,8 @@ uint64_t TargetData::getIndexedOffset(const Type *ptrTy, Value* const* Indices,
       Ty = cast<SequentialType>(Ty)->getElementType();
 
       // Get the array index and the size of each array element.
-      int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue();
-      Result += arrayIdx * (int64_t)getTypeAllocSize(Ty);
+      if (int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue())
+        Result += arrayIdx * (int64_t)getTypeAllocSize(Ty);
     }
   }
 
diff --git a/llvm/test/CodeGen/Generic/crash.ll b/llvm/test/CodeGen/Generic/crash.ll
new file mode 100644
index 00000000000..7218565617f
--- /dev/null
+++ b/llvm/test/CodeGen/Generic/crash.ll
@@ -0,0 +1,8 @@
+; RUN: llc %s -o -
+
+; PR6332
+%struct.AVCodecTag = type opaque
+@ff_codec_bmp_tags = external global [0 x %struct.AVCodecTag]
+@tags = global [1 x %struct.AVCodecTag*] [%struct.AVCodecTag* getelementptr
+inbounds ([0 x %struct.AVCodecTag]* @ff_codec_bmp_tags, i32 0, i32 0)]
+