[ARM] Use the load-acquire/store-release instructions optimally in AArch32.

[oota-llvm.git] / lib / Target / ARM / ARMBaseRegisterInfo.cpp

diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index 0e1e50e5293bf0f6b4dd30c15800e7bfe8e90aab..58c06e392cf00a3c3713905bf4e1c7bd999da074 100644 (file)
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -59,30 +59,43 @@ ARMBaseRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
   }
  
   if (ghcCall)
-    return CSR_GHC_SaveList;
+    // GHC set of callee saved regs is empty as all those regs are
+    // used for passing STG regs around
+    return CSR_NoRegs_SaveList;
   else
     return (STI.isTargetIOS() && !STI.isAAPCS_ABI())
       ? CSR_iOS_SaveList : CSR_AAPCS_SaveList;
 }
 
 const uint32_t*
-ARMBaseRegisterInfo::getCallPreservedMask(CallingConv::ID) const {
+ARMBaseRegisterInfo::getCallPreservedMask(CallingConv::ID CC) const {
+  if (CC == CallingConv::GHC)
+    // This is academic becase all GHC calls are (supposed to be) tail calls
+    return CSR_NoRegs_RegMask;
   return (STI.isTargetIOS() && !STI.isAAPCS_ABI())
     ? CSR_iOS_RegMask : CSR_AAPCS_RegMask;
 }
 
 const uint32_t*
-ARMBaseRegisterInfo::getThisReturnPreservedMask(CallingConv::ID) const {
-  return (STI.isTargetIOS() && !STI.isAAPCS_ABI())
-    ? CSR_iOS_ThisReturn_RegMask : CSR_AAPCS_ThisReturn_RegMask;
-  // This should return NULL in the case of any calling convention that does
-  // not use the same register for an i32 first argument and an i32 return
-  // value
+ARMBaseRegisterInfo::getNoPreservedMask() const {
+  return CSR_NoRegs_RegMask;
 }
 
 const uint32_t*
-ARMBaseRegisterInfo::getNoPreservedMask() const {
-  return CSR_NoRegs_RegMask;
+ARMBaseRegisterInfo::getThisReturnPreservedMask(CallingConv::ID CC) const {
+  // This should return a register mask that is the same as that returned by
+  // getCallPreservedMask but that additionally preserves the register used for
+  // the first i32 argument (which must also be the register used to return a
+  // single i32 return value)
+  //
+  // In case that the calling convention does not use the same register for
+  // both or otherwise does not want to enable this optimization, the function
+  // should return NULL
+  if (CC == CallingConv::GHC)
+    // This is academic becase all GHC calls are (supposed to be) tail calls
+    return NULL;
+  return (STI.isTargetIOS() && !STI.isAAPCS_ABI())
+    ? CSR_iOS_ThisReturn_RegMask : CSR_AAPCS_ThisReturn_RegMask;
 }
 
 BitVector ARMBaseRegisterInfo::
@@ -310,7 +323,7 @@ bool ARMBaseRegisterInfo::canRealignStack(const MachineFunction &MF) const {
   // 1. Dynamic stack realignment is explicitly disabled,
   // 2. This is a Thumb1 function (it's not useful, so we don't bother), or
   // 3. There are VLAs in the function and the base pointer is disabled.
-  if (!MF.getTarget().Options.RealignStack)
+  if (MF.getFunction()->hasFnAttribute("no-realign-stack"))
     return false;
   if (AFI->isThumb1OnlyFunction())
     return false;