From 4fd4c91c40fa40ae4cd671b03056de8c3c961046 Mon Sep 17 00:00:00 2001
From: Jim Grosbach <grosbach@apple.com>
Date: Tue, 19 Feb 2013 18:55:36 +0000
Subject: [PATCH] ARM: Allocation hints must make sure to be in the alloc
 order.

When creating an allocation hint for a register pair, make sure the hint
for the physical register reference is still in the allocation order.

rdar://13240556

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175541 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMBaseRegisterInfo.cpp        |  3 +-
 .../2013-02-19-tail-call-register-hint.ll     | 53 +++++++++++++++++++
 2 files changed, 55 insertions(+), 1 deletion(-)
 create mode 100644 test/CodeGen/Thumb2/2013-02-19-tail-call-register-hint.ll

diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index 0deafae7385..db33d540a4d 100644
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -205,7 +205,8 @@ ARMBaseRegisterInfo::getRegAllocationHints(unsigned VirtReg,
   }
 
   // First prefer the paired physreg.
-  if (PairedPhys)
+  if (PairedPhys &&
+      std::find(Order.begin(), Order.end(), PairedPhys) != Order.end())
     Hints.push_back(PairedPhys);
 
   // Then prefer even or odd registers.
diff --git a/test/CodeGen/Thumb2/2013-02-19-tail-call-register-hint.ll b/test/CodeGen/Thumb2/2013-02-19-tail-call-register-hint.ll
new file mode 100644
index 00000000000..502b138f65c
--- /dev/null
+++ b/test/CodeGen/Thumb2/2013-02-19-tail-call-register-hint.ll
@@ -0,0 +1,53 @@
+; RUN: llc < %s -mtriple=thumbv7s-apple-ios6.0.0 -verify-machineinstrs
+
+; Check to make sure the tail-call return at the end doesn't use a
+; callee-saved register. Register hinting from t2LDRDri was getting this
+; wrong. The intervening call will force allocation to try a high register
+; first, so the hint will attempt to fire, but must be rejected due to
+; not being in the allocation order for the tcGPR register class.
+; The machine instruction verifier will make sure that all actually worked
+; out the way it's supposed to.
+
+%"myclass" = type { %struct.foo }
+%struct.foo = type { i32, [40 x i8] }
+
+define hidden void @func(i8* %Data) nounwind ssp {
+  %1 = getelementptr inbounds i8* %Data, i32 12
+  %2 = bitcast i8* %1 to %"myclass"*
+  tail call void @abc(%"myclass"* %2) nounwind
+  tail call void @def(%"myclass"* %2) nounwind
+  %3 = getelementptr inbounds i8* %Data, i32 8
+  %4 = bitcast i8* %3 to i8**
+  %5 = load i8** %4, align 4, !tbaa !0
+  tail call void @ghi(i8* %5) nounwind
+  %6 = bitcast i8* %Data to void (i8*)**
+  %7 = load void (i8*)** %6, align 4, !tbaa !0
+  %8 = getelementptr inbounds i8* %Data, i32 4
+  %9 = bitcast i8* %8 to i8**
+  %10 = load i8** %9, align 4, !tbaa !0
+  %11 = icmp eq i8* %Data, null
+  br i1 %11, label %14, label %12
+
+; <label>:12                                      ; preds = %0
+  %13 = tail call %"myclass"* @jkl(%"myclass"* %2) nounwind
+  tail call void @mno(i8* %Data) nounwind
+  br label %14
+
+; <label>:14                                      ; preds = %12, %0
+  tail call void %7(i8* %10) nounwind
+  ret void
+}
+
+declare void @mno(i8*)
+
+declare void @def(%"myclass"*)
+
+declare void @abc(%"myclass"*)
+
+declare void @ghi(i8*)
+
+declare %"myclass"* @jkl(%"myclass"*) nounwind
+
+!0 = metadata !{metadata !"any pointer", metadata !1}
+!1 = metadata !{metadata !"omnipotent char", metadata !2}
+!2 = metadata !{metadata !"Simple C/C++ TBAA"}