Tighten Thumb1 branch predicate decoding.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137146 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index 8ae8ce8..42cd7ba 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -592,6 +592,9 @@
 static bool DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
                                uint64_t Address, const void *Decoder) {
   if (Val == 0xF) return false;
+  // AL predicate is not allowed on Thumb1 branches.
+  if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
+    return false;
   Inst.addOperand(MCOperand::CreateImm(Val));
   if (Val == ARMCC::AL) {
     Inst.addOperand(MCOperand::CreateReg(0));