From ef2865a8eadffd7e346b9bc70c647578010b6afd Mon Sep 17 00:00:00 2001
From: Owen Anderson <resistor@mac.com>
Date: Mon, 15 Aug 2011 23:38:54 +0000
Subject: [PATCH] Specify a necessary fixed bit for VLD3DUP, and otherwise
 rearrange the Thumb2 NEON decoding hooks to bring us closer to correctness.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137686 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMInstrFormats.td             |  6 ++-
 lib/Target/ARM/ARMInstrNEON.td                |  4 +-
 .../ARM/Disassembler/ARMDisassembler.cpp      | 37 +++++++++++--------
 3 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/lib/Target/ARM/ARMInstrFormats.td b/lib/Target/ARM/ARMInstrFormats.td
index a3bcbff21a7..ba378ed5fed 100644
--- a/lib/Target/ARM/ARMInstrFormats.td
+++ b/lib/Target/ARM/ARMInstrFormats.td
@@ -1548,7 +1548,7 @@ class NeonI<dag oops, dag iops, AddrMode am, IndexMode im, Format f,
   let AsmString = !strconcat(opc, "${p}", ".", dt, "\t", asm);
   let Pattern = pattern;
   list<Predicate> Predicates = [HasNEON];
-  let DecoderNamespace = "NEONData";
+  let DecoderNamespace = "NEON";
 }
 
 // Same as NeonI except it does not have a "data type" specifier.
@@ -1561,7 +1561,7 @@ class NeonXI<dag oops, dag iops, AddrMode am, IndexMode im, Format f,
   let AsmString = !strconcat(opc, "${p}", "\t", asm);
   let Pattern = pattern;
   list<Predicate> Predicates = [HasNEON];
-  let DecoderNamespace = "NEONData";
+  let DecoderNamespace = "NEON";
 }
 
 class NLdSt<bit op23, bits<2> op21_20, bits<4> op11_8, bits<4> op7_4,
@@ -1620,6 +1620,7 @@ class NDataI<dag oops, dag iops, Format f, InstrItinClass itin,
           pattern> {
   let Inst{31-25} = 0b1111001;
   let PostEncoderMethod = "NEONThumb2DataIPostEncoder";
+  let DecoderNamespace = "NEONData";
 }
 
 class NDataXI<dag oops, dag iops, Format f, InstrItinClass itin,
@@ -1628,6 +1629,7 @@ class NDataXI<dag oops, dag iops, Format f, InstrItinClass itin,
            cstr, pattern> {
   let Inst{31-25} = 0b1111001;
   let PostEncoderMethod = "NEONThumb2DataIPostEncoder";
+  let DecoderNamespace = "NEONData";
 }
 
 // NEON "one register and a modified immediate" format.
diff --git a/lib/Target/ARM/ARMInstrNEON.td b/lib/Target/ARM/ARMInstrNEON.td
index a8bbc9ec525..dbbf4039ff7 100644
--- a/lib/Target/ARM/ARMInstrNEON.td
+++ b/lib/Target/ARM/ARMInstrNEON.td
@@ -966,7 +966,7 @@ class VLD3DUP<bits<4> op7_4, string Dt>
           (ins addrmode6dup:$Rn), IIC_VLD3dup,
           "vld3", Dt, "\\{$Vd[], $dst2[], $dst3[]\\}, $Rn", "", []> {
   let Rm = 0b1111;
-  let Inst{4} = Rn{4};
+  let Inst{4} = 0;
   let DecoderMethod = "DecodeVLD3DupInstruction";
 }
 
@@ -989,7 +989,7 @@ class VLD3DUPWB<bits<4> op7_4, string Dt>
           (ins addrmode6dup:$Rn, am6offset:$Rm), IIC_VLD3dupu,
           "vld3", Dt, "\\{$Vd[], $dst2[], $dst3[]\\}, $Rn$Rm",
           "$Rn.addr = $wb", []> {
-  let Inst{4} = Rn{4};
+  let Inst{4} = 0;
   let DecoderMethod = "DecodeVLD3DupInstruction";
 }
 
diff --git a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index 852c52af8be..28dd986d65e 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -494,7 +494,28 @@ bool ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
   }
 
   MI.clear();
+  result = decodeNEONDupInstruction32(MI, insn32, Address, this);
+  if (result) {
+    Size = 4;
+    AddThumbPredicate(MI);
+    return true;
+  }
+
+  if (fieldFromInstruction32(insn32, 24, 8) == 0xF9) {
+    MI.clear();
+    uint32_t NEONLdStInsn = insn32;
+    NEONLdStInsn &= 0xF0FFFFFF;
+    NEONLdStInsn |= 0x04000000;
+    result = decodeNEONLoadStoreInstruction32(MI, NEONLdStInsn, Address, this);
+    if (result) {
+      Size = 4;
+      AddThumbPredicate(MI);
+      return true;
+    }
+  }
+
   if (fieldFromInstruction32(insn32, 24, 4) == 0xF) {
+    MI.clear();
     uint32_t NEONDataInsn = insn32;
     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
@@ -507,22 +528,6 @@ bool ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
     }
   }
 
-  MI.clear();
-  result = decodeNEONLoadStoreInstruction32(MI, insn32, Address, this);
-  if (result) {
-    Size = 4;
-    AddThumbPredicate(MI);
-    return true;
-  }
-
-  MI.clear();
-  result = decodeNEONDupInstruction32(MI, insn32, Address, this);
-  if (result) {
-    Size = 4;
-    AddThumbPredicate(MI);
-    return true;
-  }
-
   return false;
 }