From 8f8946389418ce3cdbf69bbf34443efe0c874b40 Mon Sep 17 00:00:00 2001
From: Eric Christopher <echristo@apple.com>
Date: Wed, 25 May 2011 20:51:58 +0000
Subject: [PATCH] Implement the 'm' modifier. Note that it only works for
 memory operands.

Part of rdar://9119939


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132081 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMAsmPrinter.cpp | 18 ++++++++++++++----
 test/CodeGen/ARM/arm-modifier.ll | 11 +++++++++++
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/lib/Target/ARM/ARMAsmPrinter.cpp b/lib/Target/ARM/ARMAsmPrinter.cpp
index 02263ee45e9..41cedab9692 100644
--- a/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -426,7 +426,6 @@ bool ARMAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
         return true;
       O << (MI->getOperand(OpNum).getImm() & 0xffff);
       return false;
-    case 'm': // The base register of a memory operand.
     case 'M': // A register range suitable for LDM/STM.
     case 'p': // The high single-precision register of a VFP double-precision
               // register.
@@ -450,9 +449,20 @@ bool ARMAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
                                           unsigned OpNum, unsigned AsmVariant,
                                           const char *ExtraCode,
                                           raw_ostream &O) {
-  if (ExtraCode && ExtraCode[0])
-    return true; // Unknown modifier.
-
+  // Does this asm operand have a single letter operand modifier?
+  if (ExtraCode && ExtraCode[0]) {
+    if (ExtraCode[1] != 0) return true; // Unknown modifier.
+    
+    switch (ExtraCode[0]) {
+      default: return true;  // Unknown modifier.
+      case 'm': // The base register of a memory operand.
+        if (!MI->getOperand(OpNum).isReg())
+          return true;
+        O << ARMInstPrinter::getRegisterName(MI->getOperand(OpNum).getReg());
+        return false;
+    }
+  }
+  
   const MachineOperand &MO = MI->getOperand(OpNum);
   assert(MO.isReg() && "unexpected inline asm memory operand");
   O << "[" << ARMInstPrinter::getRegisterName(MO.getReg()) << "]";
diff --git a/test/CodeGen/ARM/arm-modifier.ll b/test/CodeGen/ARM/arm-modifier.ll
index 91629a9ab24..6dd39897289 100644
--- a/test/CodeGen/ARM/arm-modifier.ll
+++ b/test/CodeGen/ARM/arm-modifier.ll
@@ -29,3 +29,14 @@ entry:
 call void asm sideeffect ".word ${0:L} \0A\09", "i"(i32 -1) nounwind, !srcloc !0
 ret void
 }
+
+@f2_ptr = internal global i32* @f2_var, align 4
+@f2_var = external global i32
+
+define void @f2() nounwind ssp {
+entry:
+; CHECK: f2
+; CHECK: ldr r0, [r{{[0-9]+}}]
+call void asm sideeffect "ldr r0, [${0:m}]\0A\09", "*m,~{r0}"(i32** @f2_ptr) nounwind, !srcloc !0
+ret void
+}