[IR Verifier] Do not allow bitcast of pointer to vector of pointers a…

…nd vice versa.

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.

Reviewers: arsenm
Reviewed By: arsenm
Subscribers: llvm-commits, wdng
Differential Revision: https://reviews.llvm.org/D50886

llvm-svn: 340249

llvm/lib/IR/Instructions.cpp

@@ -2978,12 +2978,14 @@ CastInst::castIsValid(Instruction::CastOps op, Value *S, Type *DstTy) {
       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)
+      return (SrcVecTy->getNumElements() == DstVecTy->getNumElements());
+    if (SrcVecTy)
+      return SrcVecTy->getNumElements() == 1;
+    if (DstVecTy)
+      return DstVecTy->getNumElements() == 1;
 
     return true;
   }

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

@@ -0,0 +1,10 @@
+; 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*> @illegal_bitcast_pointer_to_vector_of_pointers(i64* %a) {
+  %b = bitcast i64* %a to <2 x i32*>
+  ret <2 x i32*> %b
+}

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

@@ -0,0 +1,15 @@
+; 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 '<4 x i32 addrspace(1)*>' to '<2 x i32 addrspace(2)*>'
+
+; The pointer in addrspace 1 of the size 16 while pointer in addrspace 2 of the size 32.
+; Converting 4 element array of pointers from addrspace 2 to 2 element array in addrspace 2
+; has the same total bit length but bitcast still does not allow conversion into
+; different addrspace.
+define <2 x i32 addrspace(2)*> @vector_illegal_bitcast_as_1_to_2(<4 x i32 addrspace(1)*> %p) {
+   %cast = bitcast <4 x i32 addrspace(1)*> %p to <2 x i32 addrspace(2)*>
+   ret <2 x i32 addrspace(2)*> %cast
+}
+

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

@@ -0,0 +1,10 @@
+; 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* @illegal_bitcast_vector_of_pointers_to_pointer(<2 x i32*> %a) {
+  %b = bitcast <2 x i32*> %a to i64*
+  ret i64* %b
+}

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

@@ -0,0 +1,14 @@
+; 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_of_pointers(i64* %a) {
+  %b = bitcast i64* %a to <1 x i32*>
+  ret <1 x i32*> %b
+}
+
+define i64* @vector_legal_bitcast_vector_of_pointers_to_pointer(<1 x i32*> %a) {
+  %b = bitcast <1 x i32*> %a to i64*
+  ret i64* %b
+}
+