Added the B9.3.19 SUBS PC, LR, #imm (Thumb2) system instruction.

While the .td entry is nice and all, it takes a pretty gross hack in
ARMAsmParser::ParseInstruction() because of handling of other "subs"
instructions to get it to match.  Ran it by Jim Grosbach and he said it was
about what he expected to make this work given the existing code.

rdar://14214063


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187530 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 20 insertions, 0 deletions

diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 6d885a0d91..8e56a1ab94 100644
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -5138,6 +5138,26 @@ bool ARMAsmParser::ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
     }
   }
 
+  // FIXME: As said above, this is all a pretty gross hack.  This instruction
+  // does not fit with other "subs" and tblgen.
+  // Adjust operands of B9.3.19 SUBS PC, LR, #imm (Thumb2) system instruction
+  // so the Mnemonic is the original name "subs" and delete the predicate
+  // operand so it will match the table entry.
+  if (isThumbTwo() && Mnemonic == "sub" && Operands.size() == 6 &&
+      static_cast<ARMOperand*>(Operands[3])->isReg() &&
+      static_cast<ARMOperand*>(Operands[3])->getReg() == ARM::PC &&
+      static_cast<ARMOperand*>(Operands[4])->isReg() &&
+      static_cast<ARMOperand*>(Operands[4])->getReg() == ARM::LR &&
+      static_cast<ARMOperand*>(Operands[5])->isImm()) {
+    ARMOperand *Op0 = static_cast<ARMOperand*>(Operands[0]);
+    Operands.erase(Operands.begin());
+    delete Op0;
+    Operands.insert(Operands.begin(), ARMOperand::CreateToken(Name, NameLoc));
+
+    ARMOperand *Op1 = static_cast<ARMOperand*>(Operands[1]);
+    Operands.erase(Operands.begin() + 1);
+    delete Op1;
+  }
   return false;
 }