* Clean up the code a bit

* Allow structs with negative offsets.  This enables the em3d benchmark to
  be made typesafe.  In this case, the struct had an array as the first
  element, so a negative index was ok (the expr was -8 + 8x)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2271 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 8 deletions

diff --git a/lib/Transforms/TransformInternals.cpp b/lib/Transforms/TransformInternals.cpp
index 06fa27822f..55b9dda67e 100644
--- a/lib/Transforms/TransformInternals.cpp
+++ b/lib/Transforms/TransformInternals.cpp
@@ -161,15 +161,12 @@ const Type *ConvertableToGEP(const Type *Ty, Value *OffsetVal,
   //
   analysis::ExprType Expr = analysis::ClassifyExpression(OffsetVal);
 
-  // Get the offset and scale now...
+  // Get the offset and scale values if they exists...
   // A scale of zero with Expr.Var != 0 means a scale of 1.
   //
-  int Offset = 0;
-  int Scale = 0;
+  int Offset = Expr.Offset ? getConstantValue(Expr.Offset) : 0;
+  int Scale  = Expr.Scale  ? getConstantValue(Expr.Scale)  : 0;
 
-  // Get the offset and scale values if they exists...
-  if (Expr.Offset) Offset = getConstantValue(Expr.Offset);
-  if (Expr.Scale) Scale = getConstantValue(Expr.Scale);
   if (Expr.Var && Scale == 0) Scale = 1;   // Scale != 0 if Expr.Var != 0
  
   // Loop over the Scale and Offset values, filling in the Indices vector for
@@ -182,9 +179,8 @@ const Type *ConvertableToGEP(const Type *Ty, Value *OffsetVal,
     CompTy = cast<CompositeType>(NextTy);
 
     if (const StructType *StructTy = dyn_cast<StructType>(CompTy)) {
-      if (Offset < 0) return 0;  // Can't index negatively into structure
       // Step into the appropriate element of the structure...
-      unsigned ActualOffset = (unsigned)Offset;
+      unsigned ActualOffset = (Offset < 0) ? 0 : (unsigned)Offset;
       NextTy = getStructOffsetStep(StructTy, ActualOffset, Indices);
       Offset -= ActualOffset;
     } else {