From bbc71b2904644bfa85d8785328dc08d61c534467 Mon Sep 17 00:00:00 2001
From: Johnny Chen <johnny.chen@apple.com>
Date: Wed, 16 Dec 2009 02:32:54 +0000
Subject: [PATCH] Add encoding bits for some Thumb instructions.  Plus
 explicitly set the top two bytes of Inst to 0x0000 for the benefit of the
 Thumb decoder.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91496 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMInstrFormats.td | 19 +++++++++++--------
 lib/Target/ARM/ARMInstrThumb.td   |  8 ++++++--
 lib/Target/ARM/ARMInstrThumb2.td  |  1 +
 3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/lib/Target/ARM/ARMInstrFormats.td b/lib/Target/ARM/ARMInstrFormats.td
index e54ac618a65..28b2821f7fc 100644
--- a/lib/Target/ARM/ARMInstrFormats.td
+++ b/lib/Target/ARM/ARMInstrFormats.td
@@ -920,8 +920,7 @@ class T1Ix2<dag oops, dag iops, InstrItinClass itin,
   : Thumb1I<oops, iops, AddrModeNone, Size4Bytes, itin, asm, "", pattern>;
 class T1JTI<dag oops, dag iops, InstrItinClass itin,
             string asm, list<dag> pattern>
-  : Thumb1I<oops, iops, AddrModeNone, SizeSpecial, itin, asm, "", pattern>,
-    Encoding;
+  : Thumb1I<oops, iops, AddrModeNone, SizeSpecial, itin, asm, "", pattern>;
 
 // Two-address instructions
 class T1It<dag oops, dag iops, InstrItinClass itin,
@@ -986,31 +985,35 @@ class T1pIs<dag oops, dag iops,
             InstrItinClass itin, string opc, string asm, list<dag> pattern>
   : Thumb1pI<oops, iops, AddrModeT1_s, Size2Bytes, itin, opc, asm, "", pattern>;
 
+class Encoding16 : Encoding {
+  let Inst{31-16} = 0x0000;
+}
+
 // A6.2 16-bit Thumb instruction encoding
-class T1Encoding<bits<6> opcode> : Encoding {
+class T1Encoding<bits<6> opcode> : Encoding16 {
   let Inst{15-10} = opcode;
 }
 
 // A6.2.1 Shift (immediate), add, subtract, move, and compare encoding.
-class T1General<bits<5> opcode> : Encoding {
+class T1General<bits<5> opcode> : Encoding16 {
   let Inst{15-14} = 0b00;
   let Inst{13-9} = opcode;
 }
 
 // A6.2.2 Data-processing encoding.
-class T1DataProcessing<bits<4> opcode> : Encoding {
+class T1DataProcessing<bits<4> opcode> : Encoding16 {
   let Inst{15-10} = 0b010000;
   let Inst{9-6} = opcode;
 }
 
 // A6.2.3 Special data instructions and branch and exchange encoding.
-class T1Special<bits<4> opcode> : Encoding {
+class T1Special<bits<4> opcode> : Encoding16 {
   let Inst{15-10} = 0b010001;
   let Inst{9-6} = opcode;
 }
 
 // A6.2.4 Load/store single data item encoding.
-class T1LoadStore<bits<4> opA, bits<3> opB> : Encoding {
+class T1LoadStore<bits<4> opA, bits<3> opB> : Encoding16 {
   let Inst{15-12} = opA;
   let Inst{11-9} = opB;
 }
@@ -1021,7 +1024,7 @@ class T1LdSt2Imm<bits<3> opB> : T1LoadStore<0b1000, opB>; // Immediate, 2 bytes
 class T1LdStSP<bits<3> opB> : T1LoadStore<0b1001, opB>;   // SP relative
 
 // A6.2.5 Miscellaneous 16-bit instructions encoding.
-class T1Misc<bits<7> opcode> : Encoding {
+class T1Misc<bits<7> opcode> : Encoding16 {
   let Inst{15-12} = 0b1011;
   let Inst{11-5} = opcode;
 }
diff --git a/lib/Target/ARM/ARMInstrThumb.td b/lib/Target/ARM/ARMInstrThumb.td
index 6142d2e875d..dae3c22ee13 100644
--- a/lib/Target/ARM/ARMInstrThumb.td
+++ b/lib/Target/ARM/ARMInstrThumb.td
@@ -306,7 +306,11 @@ let isBranch = 1, isTerminator = 1 in {
   def tBR_JTr : T1JTI<(outs),
                       (ins tGPR:$target, jtblock_operand:$jt, i32imm:$id),
                       IIC_Br, "mov\tpc, $target\n\t.align\t2\n$jt",
-                      [(ARMbrjt tGPR:$target, tjumptable:$jt, imm:$id)]>;
+                      [(ARMbrjt tGPR:$target, tjumptable:$jt, imm:$id)]>,
+                Encoding16 {
+    let Inst{15-7} = 0b010001101;
+    let Inst{2-0} = 0b111;
+  }
   }
 }
 
@@ -596,7 +600,7 @@ def tMOVr       : T1I<(outs tGPR:$dst), (ins tGPR:$src), IIC_iMOVr,
                   T1Special<0b1000>;
 let Defs = [CPSR] in
 def tMOVSr      : T1I<(outs tGPR:$dst), (ins tGPR:$src), IIC_iMOVr,
-                       "movs\t$dst, $src", []>, Encoding {
+                       "movs\t$dst, $src", []>, Encoding16 {
   let Inst{15-6} = 0b0000000000;
 }
 
diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index 2e09cbbf44a..27c5712fd88 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -1911,6 +1911,7 @@ def t2IT : Thumb2XI<(outs), (ins it_pred:$cc, it_mask:$mask),
                     AddrModeNone, Size2Bytes,  IIC_iALUx,
                     "it$mask\t$cc", "", []> {
   // 16-bit instruction.
+  let Inst{31-16} = 0x0000;
   let Inst{15-8} = 0b10111111;
 }
 
-- 
2.34.1