Add support for the PowerPC-specific inline asm Z constraint and y modifier.

The Z constraint specifies an r+r memory address, and the y modifier expands
to the "r, r" in the asm string. For this initial implementation, the base
register is forced to r0 (which has the special meaning of 0 for r+r addressing
on PowerPC) and the full address is taken in the second register. In the
future, this should be improved.

llvm-svn: 167388

1 files changed, 16 insertions, 2 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 72395bb2839..4387730fcc1 100644
--- a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -284,8 +284,22 @@ bool PPCAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
                                           unsigned AsmVariant,
                                           const char *ExtraCode,
                                           raw_ostream &O) {
-  if (ExtraCode && ExtraCode[0])
-    return true; // Unknown modifier.
+  if (ExtraCode && ExtraCode[0]) {
+    if (ExtraCode[1] != 0) return true; // Unknown modifier.
+
+    switch (ExtraCode[0]) {
+    default: return true;  // Unknown modifier.
+    case 'y': // A memory reference for an X-form instruction
+      {
+        const char *RegName = "r0";
+        if (!Subtarget.isDarwin()) RegName = stripRegisterPrefix(RegName);
+        O << RegName << ", ";
+        printOperand(MI, OpNo, O);
+        return false;
+      }
+    }
+  }
+
   assert(MI->getOperand(OpNo).isReg());
   O << "0(";
   printOperand(MI, OpNo, O);