[llvm] r214802 - Allow CP10/CP11 operations on ARMv5/v6

[Renato Golin]

Author: rengolin
Date: Mon Aug  4 18:21:56 2014
New Revision: 214802

URL: http://llvm.org/viewvc/llvm-project?rev=214802&view=rev
Log:
Allow CP10/CP11 operations on ARMv5/v6

Those registers are VFP/NEON and vector instructions should be used instead,
but old cores rely on those co-processors to enable VFP unwinding. This change
was prompted by the libc++abi's unwinding routine and is also present in many
legacy low-level bare-metal code that we ought to compile/assemble.

Fixing bug PR20025 and allowing PR20529 to proceed with a fix in libc++abi.

Modified:
    llvm/trunk/lib/Target/ARM/AsmParser/ARMAsmParser.cpp

Modified: llvm/trunk/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/AsmParser/ARMAsmParser.cpp?rev=214802&r1=214801&r2=214802&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/AsmParser/ARMAsmParser.cpp (original)
+++ llvm/trunk/lib/Target/ARM/AsmParser/ARMAsmParser.cpp Mon Aug  4 18:21:56 2014
@@ -3118,9 +3118,10 @@ static int MatchCoprocessorOperandName(S
       return -1;
     switch (Name[1]) {
     default:  return -1;
-    // p10 and p11 are invalid for coproc instructions (reserved for FP/NEON)
-    case '0': return CoprocOp == 'p'? -1: 10;
-    case '1': return CoprocOp == 'p'? -1: 11;
+    // CP10 and CP11 are VFP/NEON and so vector instructions should be used.
+    // However, old cores (v5/v6) did use them in that way.
+    case '0': return 10;
+    case '1': return 11;
     case '2': return 12;
     case '3': return 13;
     case '4': return 14;
@@ -3177,6 +3178,9 @@ ARMAsmParser::parseCoprocNumOperand(Oper
   int Num = MatchCoprocessorOperandName(Tok.getString(), 'p');
   if (Num == -1)
     return MatchOperand_NoMatch;
+  // ARMv7 and v8 don't allow cp10/cp11 due to VFP/NEON specific instructions
+  if ((hasV7Ops() || hasV8Ops()) && (Num == 10 || Num == 11))
+    return MatchOperand_NoMatch;
 
   Parser.Lex(); // Eat identifier token.
   Operands.push_back(ARMOperand::CreateCoprocNum(Num, S));