[IR] Use immarg for preallocated intrinsics (NFC) (#155835)

Mark the attributes as immarg to indicate that they require a constant
integer. This was previously enforced with a manual verifier check.

Author: nikic

llvm/include/llvm/IR/Intrinsics.td

@@ -960,8 +960,12 @@ def int_instrprof_mcdc_tvbitmap_update : Intrinsic<[],
                                         [llvm_ptr_ty, llvm_i64_ty,
                                          llvm_i32_ty, llvm_ptr_ty]>;
 
-def int_call_preallocated_setup : DefaultAttrsIntrinsic<[llvm_token_ty], [llvm_i32_ty]>;
-def int_call_preallocated_arg : DefaultAttrsIntrinsic<[llvm_ptr_ty], [llvm_token_ty, llvm_i32_ty]>;
+def int_call_preallocated_setup
+    : DefaultAttrsIntrinsic<[llvm_token_ty], [llvm_i32_ty],
+                            [ImmArg<ArgIndex<0>>]>;
+def int_call_preallocated_arg
+    : DefaultAttrsIntrinsic<[llvm_ptr_ty], [llvm_token_ty, llvm_i32_ty],
+                            [ImmArg<ArgIndex<1>>]>;
 def int_call_preallocated_teardown : DefaultAttrsIntrinsic<[], [llvm_token_ty]>;
 
 // This intrinsic is intentionally undocumented and users shouldn't call it;

llvm/lib/IR/Verifier.cpp

@@ -5869,9 +5869,7 @@ void Verifier::visitIntrinsicCall(Intrinsic::ID ID, CallBase &Call) {
     break;
   }
   case Intrinsic::call_preallocated_setup: {
-    auto *NumArgs = dyn_cast<ConstantInt>(Call.getArgOperand(0));
-    Check(NumArgs != nullptr,
-          "llvm.call.preallocated.setup argument must be a constant");
+    auto *NumArgs = cast<ConstantInt>(Call.getArgOperand(0));
     bool FoundCall = false;
     for (User *U : Call.users()) {
       auto *UseCall = dyn_cast<CallBase>(U);

llvm/test/Verifier/preallocated-invalid.ll

@@ -65,13 +65,21 @@ define void @preallocated_one_call() {
     ret void
 }
 
-; CHECK: must be a constant
+; CHECK: immarg operand has non-immediate parameter
 define void @preallocated_setup_constant() {
     %ac = call i32 @blackbox()
     %cs = call token @llvm.call.preallocated.setup(i32 %ac)
     ret void
 }
 
+; CHECK: llvm.call.preallocated.alloc arg index must be a constant
+define void @preallocated_arg_constant() {
+    %ac = call i32 @blackbox()
+    %cs = call token @llvm.call.preallocated.setup(i32 3)
+    call token @llvm.call.preallocated.arg(token %cs, i32 %ac)
+    ret void
+}
+
 ; CHECK: must be between 0 and corresponding
 define void @preallocated_setup_arg_index_in_bounds() {
     %cs = call token @llvm.call.preallocated.setup(i32 2)