From 38fee0edcf36ea5e0541c448edf6cdead2727faf Mon Sep 17 00:00:00 2001
From: Sean Callanan <scallanan@apple.com>
Date: Tue, 15 Sep 2009 18:47:29 +0000
Subject: [PATCH] Added a new register class for segment registers to the Intel
 register table. Added 16- and 64-bit MOVs to and from the segment registers
 to the Intel instruction tables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81895 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86Instr64bit.td   | 10 ++++++++++
 lib/Target/X86/X86InstrInfo.td    | 10 ++++++++++
 lib/Target/X86/X86RegisterInfo.td |  5 +++++
 3 files changed, 25 insertions(+)

diff --git a/lib/Target/X86/X86Instr64bit.td b/lib/Target/X86/X86Instr64bit.td
index ac90357038b..b2d682c4ca6 100644
--- a/lib/Target/X86/X86Instr64bit.td
+++ b/lib/Target/X86/X86Instr64bit.td
@@ -330,6 +330,16 @@ def MOV64ao8 : RIi8<0xA2, RawFrm, (outs i8imm:$dst), (ins),
 def MOV64ao32 : RIi32<0xA3, RawFrm, (outs i32imm:$dst), (ins),
                        "mov{q}\t{%rax, $dst|$dst, %rax}", []>;
 
+// Moves to and from segment registers
+def MOV64rs : RI<0x8C, MRMDestReg, (outs GR64:$dst), (ins SEGMENT_REG:$src),
+                 "mov{w}\t{$src, $dst|$dst, $src}", []>;
+def MOV64ms : RI<0x8C, MRMDestMem, (outs i64mem:$dst), (ins SEGMENT_REG:$src),
+                 "mov{w}\t{$src, $dst|$dst, $src}", []>;
+def MOV64sr : RI<0x8E, MRMSrcReg, (outs SEGMENT_REG:$dst), (ins GR64:$src),
+                 "mov{w}\t{$src, $dst|$dst, $src}", []>;
+def MOV64sm : RI<0x8E, MRMSrcMem, (outs SEGMENT_REG:$dst), (ins i64mem:$src),
+                 "mov{w}\t{$src, $dst|$dst, $src}", []>;
+
 // Sign/Zero extenders
 
 // MOVSX64rr8 always has a REX prefix and it has an 8-bit register
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index b1f0fd8d919..734845944d3 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -946,6 +946,16 @@ def MOV16ao16 : Ii16 <0xA3, RawFrm, (outs i16imm:$dst), (ins),
 def MOV32ao32 : Ii32 <0xA3, RawFrm, (outs i32imm:$dst), (ins),
                       "mov{l}\t{%eax, $dst|$dst, %eax}", []>;
 
+// Moves to and from segment registers
+def MOV16rs : I<0x8C, MRMDestReg, (outs GR16:$dst), (ins SEGMENT_REG:$src),
+                "mov{w}\t{$src, $dst|$dst, $src}", []>;
+def MOV16ms : I<0x8C, MRMDestMem, (outs i16mem:$dst), (ins SEGMENT_REG:$src),
+                "mov{w}\t{$src, $dst|$dst, $src}", []>;
+def MOV16sr : I<0x8E, MRMSrcReg, (outs SEGMENT_REG:$dst), (ins GR16:$src),
+                "mov{w}\t{$src, $dst|$dst, $src}", []>;
+def MOV16sm : I<0x8E, MRMSrcMem, (outs SEGMENT_REG:$dst), (ins i16mem:$src),
+                "mov{w}\t{$src, $dst|$dst, $src}", []>;
+
 let canFoldAsLoad = 1, isReMaterializable = 1, mayHaveSideEffects = 1 in {
 def MOV8rm  : I<0x8A, MRMSrcMem, (outs GR8 :$dst), (ins i8mem :$src),
                 "mov{b}\t{$src, $dst|$dst, $src}",
diff --git a/lib/Target/X86/X86RegisterInfo.td b/lib/Target/X86/X86RegisterInfo.td
index c6d58e9189b..469a3d88e72 100644
--- a/lib/Target/X86/X86RegisterInfo.td
+++ b/lib/Target/X86/X86RegisterInfo.td
@@ -440,6 +440,11 @@ def GR64 : RegisterClass<"X86", [i64], 64,
   }];
 }
 
+// Segment registers for use by MOV instructions (and others) that have a
+//   segment register as one operand.  Always contain a 16-bit segment
+//   descriptor.
+def SEGMENT_REG : RegisterClass<"X86", [i16], 16, [CS, DS, SS, ES, FS, GS]> {
+}
 
 // GR8_ABCD_L, GR8_ABCD_H, GR16_ABCD, GR32_ABCD, GR64_ABCD - Subclasses of
 // GR8, GR16, GR32, and GR64 which contain just the "a" "b", "c", and "d"