The inline asm operand modifier 'c' is suppose

to be generic across architectures. It has the
following description in the gnu sources:

    Substitute immediate value without immediate syntax

Several Architectures such as x86 have local implementations
of operand modifier 'c' which go beyond the above description
slightly. To make use of the generic modifiers without overriding
local implementation one can make a call to the base class method
for AsmPrinter::PrintAsmOperand() in the locally derived method's 
"default" case in the switch statement. That way if it is already
defined locally the generic version will never get called.

This change is needed when test/CodeGen/generic/asm-large-immediate.ll
failed on a native Mips board. The test was assuming a generic
implementation was in place.

Affected files:

    lib/Target/Mips/MipsAsmPrinter.cpp:
        Changed the default case to call the base method.
    lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
        Added 'c' to the switch cases.
    test/CodeGen/Mips/asm-large-immediate.ll
        Mips compiled version of the generic one

Contributer: Jack Carter
llvm-svn: 158925

lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp

@@ -411,7 +411,21 @@ void AsmPrinter::PrintSpecial(const MachineInstr *MI, raw_ostream &OS,
 bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
     unsigned AsmVariant, const char *ExtraCode,
     raw_ostream &O) {
-  // Target doesn't support this yet!
+  // Does this asm operand have a single letter operand modifier?
+  if (ExtraCode && ExtraCode[0]) {
+    if (ExtraCode[1] != 0) return true; // Unknown modifier.
+
+    const MachineOperand &MO = MI->getOperand(OpNo);
+    switch (ExtraCode[0]) {
+    default:
+      return true;  // Unknown modifier.
+    case 'c': // Substitute immediate value without immediate syntax
+      if ((MO.getType()) != MachineOperand::MO_Immediate)
+        return true;
+      O << MO.getImm();
+      return false;
+    }
+  }
   return true;
 }
 

lib/Target/Mips/MipsAsmPrinter.cpp

@@ -301,7 +301,8 @@ bool MipsAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
     const MachineOperand &MO = MI->getOperand(OpNum);
     switch (ExtraCode[0]) {
     default:
-      return true;  // Unknown modifier.
+      // See if this is a generic print operand
+      return AsmPrinter::PrintAsmOperand(MI,OpNum,AsmVariant,ExtraCode,O);
     case 'X': // hex const int
       if ((MO.getType()) != MachineOperand::MO_Immediate)
         return true;

test/CodeGen/Mips/asm-large-immediate.ll

@@ -0,0 +1,10 @@
+; RUNx: llc -march=mipsel < %s | grep 68719476738
+
+; RUN: llc -march=mipsel < %s | FileCheck %s
+define void @test() {
+entry:
+; CHECK: /* result: 68719476738 */
+        tail call void asm sideeffect "/* result: ${0:c} */", "i,~{dirflag},~{fpsr},~{flags}"( i64 68719476738 )
+        ret void
+}
+