From 79fb3b434f83bcb7c382dbcfea485884a39b9544 Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Fri, 20 Feb 2009 20:43:02 +0000
Subject: [PATCH] Support return of MMX values in 64-bit mode.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65152 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86ISelLowering.cpp | 18 +++++++++++++++---
 test/CodeGen/X86/ret-mmx.ll        | 13 +++++++++++++
 2 files changed, 28 insertions(+), 3 deletions(-)
 create mode 100644 test/CodeGen/X86/ret-mmx.ll

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 85a6c0bb9bd..efcb3f47ff7 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1071,9 +1071,21 @@ LowerCallResult(SDValue Chain, SDValue InFlag, CallSDNode *TheCall,
       CopyVT = MVT::f80;
     }
 
-    Chain = DAG.getCopyFromReg(Chain, dl, VA.getLocReg(),
-                               CopyVT, InFlag).getValue(1);
-    SDValue Val = Chain.getValue(0);
+    SDValue Val;
+    if (Is64Bit && CopyVT.isVector() && CopyVT.getSizeInBits() == 64) {
+      // For x86-64, MMX values are returned in XMM0 and XMM1. Issue an
+      // extract_vector_elt to i64 and then bit_convert it to the desired type.
+      Chain = DAG.getCopyFromReg(Chain, dl, VA.getLocReg(),
+                                 MVT::v2i64, InFlag).getValue(1);
+      Val = Chain.getValue(0);
+      Val = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i64,
+                        Val, DAG.getConstant(0, MVT::i64));
+      Val = DAG.getNode(ISD::BIT_CONVERT, dl, CopyVT, Val);
+    } else {
+      Chain = DAG.getCopyFromReg(Chain, dl, VA.getLocReg(),
+                                 CopyVT, InFlag).getValue(1);
+      Val = Chain.getValue(0);
+    }
     InFlag = Chain.getValue(2);
 
     if (CopyVT != VA.getValVT()) {
diff --git a/test/CodeGen/X86/ret-mmx.ll b/test/CodeGen/X86/ret-mmx.ll
new file mode 100644
index 00000000000..fe9380585de
--- /dev/null
+++ b/test/CodeGen/X86/ret-mmx.ll
@@ -0,0 +1,13 @@
+; RUN: llvm-as < %s | llc -march=x86-64 -mattr=+mmx
+; rdar://6602459
+
+@g_v1di = external global <1 x i64>
+
+define void @test_v1di() nounwind {
+entry:
+	%call = call <1 x i64> @return_v1di()		; <<1 x i64>> [#uses=0]
+	store <1 x i64> %call, <1 x i64>* @g_v1di
+        ret void
+}
+
+declare <1 x i64> @return_v1di()