Make "mov" work for all Thumb2 MOV encodings

According to the ARM specification, "mov" is a valid mnemonic for all Thumb2 MOV encodings.
To achieve this, the patch adds one instruction alias with a special range condition to avoid collision with the Thumb1 MOV.

llvm-svn: 188901

3 files changed, 17 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMInstrInfo.td b/llvm/lib/Target/ARM/ARMInstrInfo.td
index 280757fb37d..3b836671ce3 100644
--- a/llvm/lib/Target/ARM/ARMInstrInfo.td
+++ b/llvm/lib/Target/ARM/ARMInstrInfo.td
@@ -710,6 +710,11 @@ def imm0_65535_expr : Operand<i32> {
   let ParserMatchClass = Imm0_65535ExprAsmOperand;
 }
 
+def Imm256_65535ExprAsmOperand: ImmAsmOperand { let Name = "Imm256_65535Expr"; }
+def imm256_65535_expr : Operand<i32> {
+  let ParserMatchClass = Imm256_65535ExprAsmOperand;
+}
+
 /// imm24b - True if the 32-bit immediate is encodable in 24 bits.
 def Imm24bitAsmOperand: ImmAsmOperand { let Name = "Imm24bit"; }
 def imm24b : Operand<i32>, ImmLeaf<i32, [{
diff --git a/llvm/lib/Target/ARM/ARMInstrThumb2.td b/llvm/lib/Target/ARM/ARMInstrThumb2.td
index 02ff08bb47c..3498e41ba1b 100644
--- a/llvm/lib/Target/ARM/ARMInstrThumb2.td
+++ b/llvm/lib/Target/ARM/ARMInstrThumb2.td
@@ -1855,6 +1855,9 @@ def t2MOVi16 : T2I<(outs rGPR:$Rd), (ins imm0_65535_expr:$imm), IIC_iMOVi,
   let DecoderMethod = "DecodeT2MOVTWInstruction";
 }
 
+def : t2InstAlias<"mov${p} $Rd, $imm", 
+                  (t2MOVi16 rGPR:$Rd, imm256_65535_expr:$imm, pred:$p)>;
+
 def t2MOVi16_ga_pcrel : PseudoInst<(outs rGPR:$Rd),
                                 (ins i32imm:$addr, pclabel:$id), IIC_iMOVi, []>;
 
diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index df9306a9b99..7467071db32 100644
--- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -867,6 +867,15 @@ public:
     int64_t Value = CE->getValue();
     return Value >= 0 && Value < 65536;
   }
+  bool isImm256_65535Expr() const {
+    if (!isImm()) return false;
+    const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(getImm());
+    // If it's not a constant expression, it'll generate a fixup and be
+    // handled later.
+    if (!CE) return true;
+    int64_t Value = CE->getValue();
+    return Value >= 256 && Value < 65536;
+  }
   bool isImm0_65535Expr() const {
     if (!isImm()) return false;
     const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(getImm());