From e7f301e079ee4b86f0a54b1108222ee3b6938ca1 Mon Sep 17 00:00:00 2001
From: Juergen Ributzka <juergen@apple.com>
Date: Fri, 29 Aug 2014 23:48:06 +0000
Subject: [PATCH] [FastISel][AArch64] Use the correct register class for
 branches.

Also constrain the register class for branches.

This fixes rdar://problem/18181496.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216804 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/AArch64/AArch64FastISel.cpp       | 16 +++++++++-------
 test/CodeGen/AArch64/arm64-fast-isel-call.ll | 15 +++++++++++++++
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/lib/Target/AArch64/AArch64FastISel.cpp b/lib/Target/AArch64/AArch64FastISel.cpp
index 7ee8c47930a..ac1b5d5fa8e 100644
--- a/lib/Target/AArch64/AArch64FastISel.cpp
+++ b/lib/Target/AArch64/AArch64FastISel.cpp
@@ -2182,15 +2182,16 @@ bool AArch64FastISel::FastLowerCall(CallLoweringInfo &CLI) {
   // Issue the call.
   MachineInstrBuilder MIB;
   if (CM == CodeModel::Small) {
-    unsigned CallOpc = Addr.getReg() ? AArch64::BLR : AArch64::BL;
-    MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(CallOpc));
+    const MCInstrDesc &II = TII.get(Addr.getReg() ? AArch64::BLR : AArch64::BL);
+    MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, II);
     if (SymName)
       MIB.addExternalSymbol(SymName, 0);
     else if (Addr.getGlobalValue())
       MIB.addGlobalAddress(Addr.getGlobalValue(), 0, 0);
-    else if (Addr.getReg())
-      MIB.addReg(Addr.getReg());
-    else
+    else if (Addr.getReg()) {
+      unsigned Reg = constrainOperandRegClass(II, Addr.getReg(), 0);
+      MIB.addReg(Reg);
+    } else
       return false;
   } else {
     unsigned CallReg = 0;
@@ -2214,8 +2215,9 @@ bool AArch64FastISel::FastLowerCall(CallLoweringInfo &CLI) {
     if (!CallReg)
       return false;
 
-    MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
-                  TII.get(AArch64::BLR)).addReg(CallReg);
+    const MCInstrDesc &II = TII.get(AArch64::BLR);
+    CallReg = constrainOperandRegClass(II, CallReg, 0);
+    MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, II).addReg(CallReg);
   }
 
   // Add implicit physical register uses to the call.
diff --git a/test/CodeGen/AArch64/arm64-fast-isel-call.ll b/test/CodeGen/AArch64/arm64-fast-isel-call.ll
index 6e22fcf7dc7..f1e2c40a33c 100644
--- a/test/CodeGen/AArch64/arm64-fast-isel-call.ll
+++ b/test/CodeGen/AArch64/arm64-fast-isel-call.ll
@@ -252,3 +252,18 @@ define void @call_arguments9(i8 %a1, i16 %a2, i32 %a3, i64 %a4, float %a5, doubl
 ; CHECK-LABEL: call_arguments9
   ret void
 }
+
+; Test that we use the correct register class for the branch.
+define void @call_blr(i64 %Fn, i1 %c) {
+; CHECK-LABEL: call_blr
+; CHECK:       blr
+  br i1 %c, label %bb1, label %bb2
+bb1:
+  %1 = inttoptr i64 %Fn to void (i64)*
+  br label %bb2
+bb2:
+  %2 = phi void (i64)* [ %1, %bb1 ], [ undef, %0 ]
+  call void %2(i64 1)
+  ret void
+}
+