From 4fd552880c9f42f117bd79929ea0179f99bd6bb7 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Tue, 7 Apr 2009 20:40:11 +0000
Subject: [PATCH] Don't attempt to handle aggregate argument values in
 FastISel; let SelectionDAG do those. This fixes PR3955.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68546 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/FastISel.cpp |  6 +++++-
 test/CodeGen/X86/fast-isel-bail.ll    | 14 ++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 test/CodeGen/X86/fast-isel-bail.ll

diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp
index 6f09f794ea4..eefe8a2884a 100644
--- a/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/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/test/CodeGen/X86/fast-isel-bail.ll b/test/CodeGen/X86/fast-isel-bail.ll
new file mode 100644
index 00000000000..fa65d209b2c
--- /dev/null
+++ b/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
+}