From ec51a6225c59fee9021b8b6c7c813228cb27a3fa Mon Sep 17 00:00:00 2001
From: Johnny Chen <johnny.chen@apple.com>
Date: Tue, 12 Apr 2011 21:41:51 +0000
Subject: [PATCH] The Thumb2 RFE instructions need to have their second
 halfword fully specified. In addition, the base register is not rGPR, but GPR
 with th exception that:

    if n == 15 then UNPREDICTABLE

rdar://problem/9273836


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129391 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMInstrThumb2.td                    | 9 +++++----
 lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h | 8 ++++++--
 test/MC/Disassembler/ARM/thumb-tests.txt            | 3 +++
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index ac963cb59ad..a560a805680 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -3228,19 +3228,20 @@ class T2RFE<bits<12> op31_20, dag oops, dag iops, InstrItinClass itin,
 
   bits<4> Rn;
   let Inst{19-16} = Rn;
+  let Inst{15-0} = 0xc000;
 }
 
 def t2RFEDBW : T2RFE<0b111010000011,
-                   (outs), (ins rGPR:$Rn), NoItinerary, "rfedb", "\t$Rn!",
+                   (outs), (ins GPR:$Rn), NoItinerary, "rfedb", "\t$Rn!",
                    [/* For disassembly only; pattern left blank */]>;
 def t2RFEDB  : T2RFE<0b111010000001,
-                   (outs), (ins rGPR:$Rn), NoItinerary, "rfeab", "\t$Rn",
+                   (outs), (ins GPR:$Rn), NoItinerary, "rfedb", "\t$Rn",
                    [/* For disassembly only; pattern left blank */]>;
 def t2RFEIAW : T2RFE<0b111010011011,
-                   (outs), (ins rGPR:$Rn), NoItinerary, "rfeia", "\t$Rn!",
+                   (outs), (ins GPR:$Rn), NoItinerary, "rfeia", "\t$Rn!",
                    [/* For disassembly only; pattern left blank */]>;
 def t2RFEIA  : T2RFE<0b111010011001,
-                   (outs), (ins rGPR:$Rn), NoItinerary, "rfeia", "\t$Rn",
+                   (outs), (ins GPR:$Rn), NoItinerary, "rfeia", "\t$Rn",
                    [/* For disassembly only; pattern left blank */]>;
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h b/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
index 3d2d1ab947f..e29d84604ec 100644
--- a/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
+++ b/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
@@ -1142,8 +1142,12 @@ static bool DisassembleThumb2SRS(MCInst &MI, unsigned Opcode, uint32_t insn,
 // t2RFE[IA|DB]W/t2RFE[IA|DB]: Rn
 static bool DisassembleThumb2RFE(MCInst &MI, unsigned Opcode, uint32_t insn,
     unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
-  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
-                                                     decodeRn(insn))));
+  unsigned Rn = decodeRn(insn);
+  if (Rn == 15) {
+    DEBUG(errs() << "if n == 15 then UNPREDICTABLE\n");
+    return false;
+  }
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B,ARM::GPRRegClassID,Rn)));
   NumOpsAdded = 1;
   return true;
 }
diff --git a/test/MC/Disassembler/ARM/thumb-tests.txt b/test/MC/Disassembler/ARM/thumb-tests.txt
index 609cd6badeb..ce447b61c7b 100644
--- a/test/MC/Disassembler/ARM/thumb-tests.txt
+++ b/test/MC/Disassembler/ARM/thumb-tests.txt
@@ -238,3 +238,6 @@
 
 # CHECK:	svc	#230
 0xe6 0xdf
+
+# CHECK:	rfedb	lr
+0x1e 0xe8 0x00 0xc0