[arm] Recognize SXTB, SXTH, UXTB and UXTH.

src/arm/assembler-arm.h

Index: src/arm/assembler-arm.h
diff --git a/src/arm/assembler-arm.h b/src/arm/assembler-arm.h
index 9087fab56a41b6fe2f2ff24f5bae1a74613355fa..54c927826e849b2702cdeab7ee2a005e95f29795 100644
--- a/src/arm/assembler-arm.h
+++ b/src/arm/assembler-arm.h
@@ -1034,12 +1034,20 @@ class Assembler : public AssemblerBase {
   void pkhtb(Register dst, Register src1, const Operand& src2,
              Condition cond = al);
 
-  void uxtb(Register dst, const Operand& src, Condition cond = al);
-
-  void uxtab(Register dst, Register src1, const Operand& src2,
+  void sxtb(Register dst, Register src, int rotate = 0, Condition cond = al);
+  void sxtab(Register dst, Register src1, Register src2, int rotate = 0,
+             Condition cond = al);
+  void sxth(Register dst, Register src, int rotate = 0, Condition cond = al);
+  void sxtah(Register dst, Register src1, Register src2, int rotate = 0,
              Condition cond = al);
 
-  void uxtb16(Register dst, const Operand& src, Condition cond = al);
+  void uxtb(Register dst, Register src, int rotate = 0, Condition cond = al);
+  void uxtab(Register dst, Register src1, Register src2, int rotate = 0,
+             Condition cond = al);
+  void uxtb16(Register dst, Register src, int rotate = 0, Condition cond = al);
+  void uxth(Register dst, Register src, int rotate = 0, Condition cond = al);
+  void uxtah(Register dst, Register src1, Register src2, int rotate = 0,
+             Condition cond = al);
 
   // Status register access instructions