Fix PR1749 and InstCombine/2007-10-28-EmptyField.ll by handling
zero-length fields better.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43427 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/TargetData.cpp b/lib/Target/TargetData.cpp
index b2d76d8..b1b78a8 100644
--- a/lib/Target/TargetData.cpp
+++ b/lib/Target/TargetData.cpp
@@ -83,9 +83,15 @@
assert(SI != &MemberOffsets[0] && "Offset not in structure type!");
--SI;
assert(*SI <= Offset && "upper_bound didn't work");
- assert((SI == &MemberOffsets[0] || *(SI-1) < Offset) &&
+ assert((SI == &MemberOffsets[0] || *(SI-1) <= Offset) &&
(SI+1 == &MemberOffsets[NumElements] || *(SI+1) > Offset) &&
"Upper bound didn't work!");
+
+ // Multiple fields can have the same offset if any of them are zero sized.
+ // For example, in { i32, [0 x i32], i32 }, searching for offset 4 will stop
+ // at the i32 element, because it is the last element at that offset. This is
+ // the right one to return, because anything after it will have a higher
+ // offset, implying that this element is non-empty.
return SI-&MemberOffsets[0];
}