Fix pr13145 - Naming a function like a register name confuses the asm parser.

Patch by Stepan Dyatkovskiy <stpworld@narod.ru>
rdar://13457826

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177463 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/AsmParser/ARMAsmParser.cpp

@@ -4593,6 +4593,11 @@ bool ARMAsmParser::parseOperand(SmallVectorImpl<MCParsedAsmOperand*> &Operands,
     Error(Parser.getTok().getLoc(), "unexpected token in operand");
     return true;
   case AsmToken::Identifier: {
+    // If we've seen a branch mnemonic, the next operand must be a label.  This
+    // is true even if the label is a register name.  So "br r1" means branch to
+    // label "r1".
+    bool ExpectLabel = Mnemonic == "b" || Mnemonic == "bl";
+    if (!ExpectLabel) {
       if (!tryParseRegisterWithWriteBack(Operands))
         return false;
       int Res = tryParseShiftRegister(Operands);
@@ -4608,6 +4613,7 @@ bool ARMAsmParser::parseOperand(SmallVectorImpl<MCParsedAsmOperand*> &Operands,
         Operands.push_back(ARMOperand::CreateToken("APSR_nzcv", S));
         return false;
       }
+    }
 
     // Fall though for the Identifier case that is not a register or a
     // special name.

test/MC/ARM/2013-03-18-Br-to-label-named-like-reg.s

@@ -0,0 +1,5 @@
+@ RUN: llvm-mc -arch arm %s
+@ CHECK: test:
+@ CHECK: br r1
+test:
+  bl r1