Revise ARM inline assembly memory operands to require the memory address to

be in a register.  The previous use of ARM address mode 2 was completely
arbitrary and inappropriate for Thumb.  Radar 7137468.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84022 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 11 insertions, 10 deletions

diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index b0b100c8ef..1651851761 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -2156,14 +2156,10 @@ bool ARMDAGToDAGISel::
 SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
                              std::vector<SDValue> &OutOps) {
   assert(ConstraintCode == 'm' && "unexpected asm memory constraint");
-
-  SDValue Base, Offset, Opc;
-  if (!SelectAddrMode2(Op, Op, Base, Offset, Opc))
-    return true;
-
-  OutOps.push_back(Base);
-  OutOps.push_back(Offset);
-  OutOps.push_back(Opc);
+  // Require the address to be in a register.  That is safe for all ARM
+  // variants and it is hard to do anything much smarter without knowing
+  // how the operand is used.
+  OutOps.push_back(Op);
   return false;
 }
 
diff --git a/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp b/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
index 1679e12be0..546731b00d 100644
--- a/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
@@ -1017,7 +1017,10 @@ bool ARMAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
                                           const char *ExtraCode) {
   if (ExtraCode && ExtraCode[0])
     return true; // Unknown modifier.
-  printAddrMode2Operand(MI, OpNum);
+
+  const MachineOperand &MO = MI->getOperand(OpNum);
+  assert(MO.isReg() && "unexpected inline asm memory operand");
+  O << "[" << getRegisterName(MO.getReg()) << "]";
   return false;
 }
 
diff --git a/test/CodeGen/ARM/2009-05-18-InlineAsmMem.ll b/test/CodeGen/ARM/2009-05-18-InlineAsmMem.ll
index 2fc9eb3741..1e2707f7b5 100644
--- a/test/CodeGen/ARM/2009-05-18-InlineAsmMem.ll
+++ b/test/CodeGen/ARM/2009-05-18-InlineAsmMem.ll
@@ -1,7 +1,9 @@
-; RUN: llc < %s -march=arm | grep swp
+; RUN: llc < %s -march=arm | FileCheck %s
+; RUN: llc < %s -march=thumb | FileCheck %s
 ; PR4091
 
 define void @foo(i32 %i, i32* %p) nounwind {
+;CHECK: swp r2, r0, [r1]
 	%asmtmp = call i32 asm sideeffect "swp $0, $2, $3", "=&r,=*m,r,*m,~{memory}"(i32* %p, i32 %i, i32* %p) nounwind
 	ret void
 }