[mips][mips64r6] ll, sc, lld, and scd are re-encoded on MIPS32r6/MIPS64r6.

Summary:
The linked-load, store-conditional operations have been re-encoded such
that have a 9-bit offset instead of the 16-bit offset they have prior to
MIPS32r6/MIPS64r6.

While implementing this, I noticed that the atomic load/store pseudos always
emit a sign extension using sll and sra. I have improved this to use seb/seh
when they are available (MIPS32r2/MIPS64r2 and above).

Depends on D4118

Reviewers: jkolek, zoran.jovanovic, vmedic

Reviewed By: vmedic

Differential Revision: http://reviews.llvm.org/D4119

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211018 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 24 insertions, 0 deletions

diff --git a/lib/Target/Mips/Mips32r6InstrFormats.td b/lib/Target/Mips/Mips32r6InstrFormats.td
index 6eb8c4650c..697d550615 100644
--- a/lib/Target/Mips/Mips32r6InstrFormats.td
+++ b/lib/Target/Mips/Mips32r6InstrFormats.td
@@ -39,6 +39,7 @@ def OPGROUP_DAUI     : OPGROUP<0b011101>;
 def OPGROUP_PCREL    : OPGROUP<0b111011>;
 def OPGROUP_REGIMM   : OPGROUP<0b000001>;
 def OPGROUP_SPECIAL  : OPGROUP<0b000000>;
+// The spec occasionally names this value LL, LLD, SC, or SCD.
 def OPGROUP_SPECIAL3 : OPGROUP<0b011111>;
 // The spec names this constant LWC2, LDC2, SWC2, and SDC2 in different places.
 def OPGROUP_COP2LDST : OPGROUP<0b010010>;
@@ -84,6 +85,12 @@ def OPCODE6_DBITSWAP : OPCODE6<0b100100>;
 def OPCODE6_JALR     : OPCODE6<0b001001>;
 def OPCODE6_CACHE    : OPCODE6<0b100101>;
 def OPCODE6_PREF     : OPCODE6<0b110101>;
+// The next four constants are unnamed in the spec. These names are taken from
+// the OPGROUP names they are used with.
+def OPCODE6_LL       : OPCODE6<0b110110>;
+def OPCODE6_LLD      : OPCODE6<0b110111>;
+def OPCODE6_SC       : OPCODE6<0b100110>;
+def OPCODE6_SCD      : OPCODE6<0b100111>;
 
 class FIELD_FMT<bits<5> Val> {
   bits<5> Value = Val;
@@ -411,6 +418,23 @@ class SPECIAL3_DALIGN_FM<OPCODE6 Operation> : MipsR6Inst {
   let Inst{5-0}   = Operation.Value;
 }
 
+class SPECIAL3_LL_SC_FM<OPCODE6 Operation> : MipsR6Inst {
+  bits<5> rt;
+  bits<21> addr;
+  bits<5> base = addr{20-16};
+  bits<9> offset = addr{8-0};
+
+  bits<32> Inst;
+
+  let Inst{31-26} = OPGROUP_SPECIAL3.Value;
+  let Inst{25-21} = base;
+  let Inst{20-16} = rt;
+  let Inst{15-7} = offset;
+  let Inst{5-0} = Operation.Value;
+
+  string DecoderMethod = "DecodeSpecial3LlSc";
+}
+
 class REGIMM_FM<OPCODE5 Operation> : MipsR6Inst {
   bits<5> rs;
   bits<16> imm;