[IR Verifier] Do not allow bitcast of pointer to vector of pointers and vice versa.

[skatkov]

Summary

LangRef for BitCast requires that
"The bit sizes of value and the destination type, ty2, must be identical".
Currently verifier allows BitCast of pointer to vector of pointers so that
the sizes are different.

This change fixes that.

[arsenm]

test/Verifier/bitcast-pointer-vector-neg.ll

7

Test names are misleading, these aren't pointers to vector

10

Should also include tests where the pointers are in a different address space with a different size (such that the total sizes match) for good measure

[skatkov]

test/Verifier/bitcast-pointer-vector-neg.ll

7

I'm sorry but I do not follow this comment...
The test represents bitcast of pointer to vector.
Will the name illegal_bitcast_pointer_to_vector_of_pointers fits better?

[arsenm]

LGTM

lib/IR/Instructions.cpp

case Instruction::BitCast: {
     if (!SrcPtrTy)
       return SrcTy->getPrimitiveSizeInBits() == DstTy->getPrimitiveSizeInBits();
 
     // If both are pointers then the address spaces must match.
     if (SrcPtrTy->getAddressSpace() != DstPtrTy->getAddressSpace())
       return false;
 
     // A vector of pointers must have the same number of elements.
-    if (VectorType *SrcVecTy = dyn_cast<VectorType>(SrcTy)) {
-      if (VectorType *DstVecTy = dyn_cast<VectorType>(DstTy))
-        return (SrcVecTy->getNumElements() == DstVecTy->getNumElements());
-
-      return false;
-    }
+    VectorType *SrcVecTy = dyn_cast<VectorType>(SrcTy);
+    VectorType *DstVecTy = dyn_cast<VectorType>(DstTy);
+    if (SrcVecTy && DstVecTy)
+    if (SrcVecTy)
+      return SrcVecTy->getNumElements() == 1;
+    if (DstVecTy)
+      return DstVecTy->getNumElements() == 1;
 
     return true;
   }
   case Instruction::AddrSpaceCast: {
     PointerType *SrcPtrTy = dyn_cast<PointerType>(SrcTy->getScalarType());
     if (!SrcPtrTy)
       return false;
 

test/Verifier/bitcast-pointer-vector-neg.ll

+; RUN: not llvm-as -disable-output %s 2>&1 | FileCheck %s
+
+target datalayout = "e-p:32:32:32-p1:16:16:16-p2:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n8:16:32"
+
+; CHECK: error: invalid cast opcode for cast from 'i64*' to '<2 x i32*>'
+
+define <2 x i32*> @vector_illegal_bitcast_pointer_to_vector(i64* %a) {
+  %b = bitcast i64* %a to <2 x i32*>
+  ret <2 x i32*> %b
+}

test/Verifier/bitcast-vector-pointer-neg.ll

+; RUN: not llvm-as -disable-output %s 2>&1 | FileCheck %s
+
+target datalayout = "e-p:32:32:32-p1:16:16:16-p2:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n8:16:32"
+
+; CHECK: error: invalid cast opcode for cast from '<2 x i32*>' to 'i64*'
+
+define i64* @vector_illegal_bitcast_vector_to_pointer(<2 x i32*> %a) {
+  %b = bitcast <2 x i32*> %a to i64*
+  ret i64* %b
+}

test/Verifier/bitcast-vector-pointer-pos.ll

+; RUN: llvm-as -disable-output %s
+
+target datalayout = "e-p:32:32:32-p1:16:16:16-p2:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n8:16:32"
+
+define <1 x i32*> @vector_legal_bitcast_pointer_to_vector(i64* %a) {
+  %b = bitcast i64* %a to <1 x i32*>
+  ret <1 x i32*> %b
+}
+
+define i64* @vector_legal_bitcast_vector_to_pointer(<1 x i32*> %a) {
+  %b = bitcast <1 x i32*> %a to i64*
+  ret i64* %b
+}
+