Thumb assembly parsing and encoding for LDR(immediate) form T1.

llvm-svn: 138047

2 files changed, 20 insertions, 1 deletions

diff --git a/llvm/lib/Target/ARM/ARMInstrThumb.td b/llvm/lib/Target/ARM/ARMInstrThumb.td
index a6e0ed737ba..8d4fa19d9f2 100644
--- a/llvm/lib/Target/ARM/ARMInstrThumb.td
+++ b/llvm/lib/Target/ARM/ARMInstrThumb.td
@@ -157,11 +157,13 @@ def t_addrmode_rrs4 : Operand<i32>,
 
 // t_addrmode_is4 := reg + imm5 * 4
 //
+def t_addrmode_is4_asm_operand : AsmOperandClass { let Name = "MemThumbRIs4"; }
 def t_addrmode_is4 : Operand<i32>,
                      ComplexPattern<i32, 2, "SelectThumbAddrModeImm5S4", []> {
   let EncoderMethod = "getAddrModeISOpValue";
   let DecoderMethod = "DecodeThumbAddrModeIS";
   let PrintMethod = "printThumbAddrModeImm5S4Operand";
+  let ParserMatchClass = t_addrmode_is4_asm_operand;
   let MIOperandInfo = (ops tGPR:$base, i32imm:$offsimm);
 }
 
diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 69775455111..9658e0801df 100644
--- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -616,7 +616,17 @@ public:
     if (Kind != Memory || !Mem.OffsetRegNum || Mem.isNegative ||
         Mem.ShiftType != ARM_AM::no_shift)
       return false;
-    return true;
+    return isARMLowRegister(Mem.BaseRegNum) &&
+      (!Mem.OffsetRegNum || isARMLowRegister(Mem.OffsetRegNum));
+  }
+  bool isMemThumbRIs4() const {
+    if (Kind != Memory || Mem.OffsetRegNum != 0 ||
+        !isARMLowRegister(Mem.BaseRegNum))
+      return false;
+    // Immediate offset, multiple of 4 in range [0, 124].
+    if (!Mem.OffsetImm) return true;
+    int64_t Val = Mem.OffsetImm->getValue();
+    return Val >= 0 && Val < 125 && (Val % 4) == 0;
   }
   bool isMemImm8Offset() const {
     if (Kind != Memory || Mem.OffsetRegNum != 0)
@@ -975,6 +985,13 @@ public:
     Inst.addOperand(MCOperand::CreateReg(Mem.OffsetRegNum));
   }
 
+  void addMemThumbRIs4Operands(MCInst &Inst, unsigned N) const {
+    assert(N == 2 && "Invalid number of operands!");
+    int64_t Val = Mem.OffsetImm ? (Mem.OffsetImm->getValue() / 4) : 0;
+    Inst.addOperand(MCOperand::CreateReg(Mem.BaseRegNum));
+    Inst.addOperand(MCOperand::CreateImm(Val));
+  }
+
   void addPostIdxImm8Operands(MCInst &Inst, unsigned N) const {
     assert(N == 1 && "Invalid number of operands!");
     const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(getImm());