Don't attempt to handle aggregate argument values in FastISel; let

SelectionDAG do those. This fixes PR3955.

llvm-svn: 68546

2 files changed, 19 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
index 6f09f794ea4..eefe8a2884a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -57,11 +57,15 @@
 using namespace llvm;
 
 unsigned FastISel::getRegForValue(Value *V) {
-  MVT::SimpleValueType VT = TLI.getValueType(V->getType()).getSimpleVT();
+  MVT RealVT = TLI.getValueType(V->getType(), /*AllowUnknown=*/true);
+  // Don't handle non-simple values in FastISel.
+  if (!RealVT.isSimple())
+    return 0;
 
   // Ignore illegal types. We must do this before looking up the value
   // in ValueMap because Arguments are given virtual registers regardless
   // of whether FastISel can handle them.
+  MVT::SimpleValueType VT = RealVT.getSimpleVT();
   if (!TLI.isTypeLegal(VT)) {
     // Promote MVT::i1 to a legal type though, because it's common and easy.
     if (VT == MVT::i1)
diff --git a/llvm/test/CodeGen/X86/fast-isel-bail.ll b/llvm/test/CodeGen/X86/fast-isel-bail.ll
new file mode 100644
index 00000000000..fa65d209b2c
--- /dev/null
+++ b/llvm/test/CodeGen/X86/fast-isel-bail.ll
@@ -0,0 +1,14 @@
+; RUN: llvm-as < %s | llc -march=x86 -fast
+
+; This file is for regression tests for cases where FastISel needs
+; to gracefully bail out and let SelectionDAGISel take over.
+
+	type { i64, i8* }		; type %0
+
+declare void @bar(%0)
+
+define fastcc void @foo() nounwind {
+entry:
+	call void @bar(%0 zeroinitializer)
+	unreachable
+}