Separate out Thumb1 instructions that need an S bit operand from those that do not, for the purposes of decoding them.

llvm-svn: 137787

2 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMInstrFormats.td b/llvm/lib/Target/ARM/ARMInstrFormats.td
index fecc6bfdef8..ef5834b0acf 100644
--- a/llvm/lib/Target/ARM/ARMInstrFormats.td
+++ b/llvm/lib/Target/ARM/ARMInstrFormats.td
@@ -902,6 +902,7 @@ class Thumb1sI<dag oops, dag iops, AddrMode am, int sz,
   let Pattern = pattern;
   let thumbArithFlagSetting = 1;
   list<Predicate> Predicates = [IsThumb, IsThumb1Only];
+  let DecoderNamespace = "ThumbSBit";
 }
 
 class T1sI<dag oops, dag iops, InstrItinClass itin,
diff --git a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index 28dd986d65e..cb7a45a2572 100644
--- a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -417,6 +417,14 @@ bool ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
   bool result = decodeThumbInstruction16(MI, insn16, Address, this);
   if (result) {
     Size = 2;
+    AddThumbPredicate(MI);
+    return true;
+  }
+
+  MI.clear();
+  result = decodeThumbSBitInstruction16(MI, insn16, Address, this);
+  if (result) {
+    Size = 2;
     bool InITBlock = !ITBlock.empty();
     AddThumbPredicate(MI);
     AddThumb1SBit(MI, InITBlock);