[IR] Make VPIntrinsic::getDeclarationForParams() opaque pointer compatible

The vp.load and vp.gather intrinsics require the intrinsic return
type to determine the correct function signature. With opaque pointers,
it cannot be derived from the parameter pointee types.

Differential Revision: https://reviews.llvm.org/D115632

Author: nikic

llvm/include/llvm/IR/IntrinsicInst.h

@@ -390,8 +390,10 @@ class DbgLabelInst : public DbgInfoIntrinsic {
 class VPIntrinsic : public IntrinsicInst {
 public:
   /// \brief Declares a llvm.vp.* intrinsic in \p M that matches the parameters
-  /// \p Params.
+  /// \p Params. Additionally, the load and gather intrinsics require
+  /// \p ReturnType to be specified.
   static Function *getDeclarationForParams(Module *M, Intrinsic::ID,
+                                           Type *ReturnType,
                                            ArrayRef<Value *> Params);
 
   static Optional<unsigned> getMaskParamPos(Intrinsic::ID IntrinsicID);

llvm/lib/IR/IntrinsicInst.cpp

@@ -468,6 +468,7 @@ bool VPIntrinsic::canIgnoreVectorLengthParam() const {
 }
 
 Function *VPIntrinsic::getDeclarationForParams(Module *M, Intrinsic::ID VPID,
+                                               Type *ReturnType,
                                                ArrayRef<Value *> Params) {
   assert(isVPIntrinsic(VPID) && "not a VP intrinsic");
   Function *VPFunc;
@@ -486,22 +487,15 @@ Function *VPIntrinsic::getDeclarationForParams(Module *M, Intrinsic::ID VPID,
     break;
   case Intrinsic::vp_load:
     VPFunc = Intrinsic::getDeclaration(
-        M, VPID,
-        {Params[0]->getType()->getPointerElementType(), Params[0]->getType()});
+        M, VPID, {ReturnType, Params[0]->getType()});
     break;
   case Intrinsic::vp_gather:
     VPFunc = Intrinsic::getDeclaration(
-        M, VPID,
-        {VectorType::get(cast<VectorType>(Params[0]->getType())
-                             ->getElementType()
-                             ->getPointerElementType(),
-                         cast<VectorType>(Params[0]->getType())),
-         Params[0]->getType()});
+        M, VPID, {ReturnType, Params[0]->getType()});
     break;
   case Intrinsic::vp_store:
     VPFunc = Intrinsic::getDeclaration(
-        M, VPID,
-        {Params[1]->getType()->getPointerElementType(), Params[1]->getType()});
+        M, VPID, {Params[0]->getType(), Params[1]->getType()});
     break;
   case Intrinsic::vp_scatter:
     VPFunc = Intrinsic::getDeclaration(

llvm/unittests/IR/VPIntrinsicTest.cpp

@@ -272,7 +272,7 @@ TEST_F(VPIntrinsicTest, VPIntrinsicDeclarationForParams) {
 
     ASSERT_NE(F.getIntrinsicID(), Intrinsic::not_intrinsic);
     auto *NewDecl = VPIntrinsic::getDeclarationForParams(
-        OutM.get(), F.getIntrinsicID(), Values);
+        OutM.get(), F.getIntrinsicID(), FuncTy->getReturnType(), Values);
     ASSERT_TRUE(NewDecl);
 
     // Check that 'old decl' == 'new decl'.