Bitcasting two or from aggregate types is not permitted. Update
LangRef.html, and teach the verifier to check bitcast instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55921 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LangRef.html b/docs/LangRef.html
index 8994a35..1beb670 100644
--- a/docs/LangRef.html
+++ b/docs/LangRef.html
@@ -1729,7 +1729,8 @@
was stored to memory and read back as TYPE. In other words, no bits change
with this operator, just the type. This can be used for conversion of
vector types to any other type, as long as they have the same bit width. For
- pointers it is only valid to cast to another pointer type.
+ pointers it is only valid to cast to another pointer type. It is not valid
+ to bitcast to or from an aggregate type.
</dd>
<dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
@@ -3808,8 +3809,9 @@
<h5>Arguments:</h5>
<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
-a first class value, and a type to cast it to, which must also be a <a
- href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
+a non-aggregate first class value, and a type to cast it to, which must also be
+a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
+<tt>value</tt>
and the destination type, <tt>ty2</tt>, must be identical. If the source
type is a pointer, the destination type must also be a pointer. This
instruction supports bitwise conversion of vectors to integers and to vectors
diff --git a/lib/VMCore/Verifier.cpp b/lib/VMCore/Verifier.cpp
index aa6963d..805fb25 100644
--- a/lib/VMCore/Verifier.cpp
+++ b/lib/VMCore/Verifier.cpp
@@ -883,6 +883,12 @@
"Bitcast requires both operands to be pointer or neither", &I);
Assert1(SrcBitSize == DestBitSize, "Bitcast requies types of same width", &I);
+ // Disallow aggregates.
+ Assert1(!SrcTy->isAggregateType(),
+ "Bitcast operand must not be aggregate", &I);
+ Assert1(!DestTy->isAggregateType(),
+ "Bitcast type must not be aggregate", &I);
+
visitInstruction(I);
}