Remove an over-aggressive assert. Functions with empty struct return

types don't have any return values, from CodeGen's perspective.
This fixes PR4688.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78311 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 50 insertions, 3 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
index 1eb87e888c..d90b9680aa 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
@@ -4468,9 +4468,6 @@ void SelectionDAGLowering::LowerCallTo(CallSite CS, SDValue Callee,
                     isTailCall,
                     !CS.getInstruction()->use_empty(),
                     Callee, Args, DAG, getCurDebugLoc());
-  assert((isTailCall || CS.getType() == Type::VoidTy ||
-          Result.first.getNode()) &&
-         "Non-null value expected with non-void non-tail call!");
   assert((isTailCall || Result.second.getNode()) &&
          "Non-null chain expected with non-tail call!");
   assert((Result.second.getNode() || !Result.first.getNode()) &&
diff --git a/test/CodeGen/X86/empty-struct-return-type.ll b/test/CodeGen/X86/empty-struct-return-type.ll
new file mode 100644
index 0000000000..d398cb9837
--- /dev/null
+++ b/test/CodeGen/X86/empty-struct-return-type.ll
@@ -0,0 +1,50 @@
+; RUN: llvm-as < %s | llc -march=x86-64 | grep call | count 3
+; PR4688
+
+; Return types can be empty structs, which can be awkward.
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-unknown-linux-gnu"
+	%llvm.fe.ty10 = type %struct.pthread_attr_t*
+	%llvm.fe.ty11 = type i8* (i8*)
+	%llvm.fe.ty12 = type %llvm.fe.ty11*
+	%llvm.fe.ty13 = type %struct.__pthread_list_t*
+	%llvm.fe.ty15 = type %struct.pthread_mutex_t*
+	%llvm.fe.ty17 = type %struct.QBasicAtomicInt*
+	%llvm.fe.ty18 = type void (i8*)
+	%llvm.fe.ty19 = type %llvm.fe.ty18*
+	%llvm.fe.ty3 = type void ()
+	%llvm.fe.ty4 = type %llvm.fe.ty3*
+	%struct..0KnownPointers = type { %struct.QMutex, %"struct.QHash<void*,QHashDummyValue>" }
+	%struct..0__pthread_mutex_s = type { i32, i32, i32, i32, i32, i32, %struct.__pthread_list_t }
+	%struct.QBasicAtomicInt = type { i32 }
+	%"struct.QHash<void*,QHashDummyValue>" = type { %"struct.QHash<void*,QHashDummyValue>::._177" }
+	%"struct.QHash<void*,QHashDummyValue>::._177" = type { %struct.QHashData* }
+	%struct.QHashData = type { %"struct.QHashData::Node"*, %"struct.QHashData::Node"**, %struct.QBasicAtomicInt, i32, i32, i16, i16, i32, i8 }
+	%"struct.QHashData::Node" = type { %"struct.QHashData::Node"*, i32 }
+	%struct.QMutex = type { %struct.QMutexPrivate* }
+	%struct.QMutexPrivate = type opaque
+	%struct.__pthread_list_t = type { %llvm.fe.ty13, %llvm.fe.ty13 }
+	%struct.pthread_attr_t = type { i64, [48 x i8] }
+	%struct.pthread_mutex_t = type { %struct..0__pthread_mutex_s }
+
+define void @_ZN15QtSharedPointer22internalSafetyCheckAddEPVKv(i8* %ptr) {
+entry:
+	%0 = invoke fastcc %struct..0KnownPointers* @_ZL13knownPointersv()
+			to label %invcont1 unwind label %lpad		; <%struct..0KnownPointers*> [#uses=0]
+
+invcont1:		; preds = %entry
+	%1 = invoke fastcc %struct..0KnownPointers* @_ZL13knownPointersv()
+			to label %invcont3 unwind label %lpad		; <%struct..0KnownPointers*> [#uses=0]
+
+invcont3:		; preds = %invcont1
+	%2 = call { } @_ZNK5QHashIPv15QHashDummyValueE5valueERKS0_(%"struct.QHash<void*,QHashDummyValue>"* undef, i8** undef)		; <{ }> [#uses=0]
+	unreachable
+
+lpad:		; preds = %invcont1, %entry
+	unreachable
+}
+
+declare hidden { } @_ZNK5QHashIPv15QHashDummyValueE5valueERKS0_(%"struct.QHash<void*,QHashDummyValue>"*, i8** nocapture) nounwind
+
+declare fastcc %struct..0KnownPointers* @_ZL13knownPointersv()