[X86] Basic additions to support RegCall Calling Convention.

The Register Calling Convention (RegCall) was introduced by Intel to optimize parameter transfer on function call.
This calling convention ensures that as many values as possible are passed or returned in registers.
This commit presents the basic additions to LLVM CodeGen in order to support RegCall in X86.

Differential Revision: http://reviews.llvm.org/D25022

llvm-svn: 284108

1 files changed, 26 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/X86RegisterInfo.cpp b/llvm/lib/Target/X86/X86RegisterInfo.cpp
index 87175c32ddc..33af73c5308 100644
--- a/llvm/lib/Target/X86/X86RegisterInfo.cpp
+++ b/llvm/lib/Target/X86/X86RegisterInfo.cpp
@@ -305,6 +305,19 @@ X86RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
   }
   case CallingConv::HHVM:
     return CSR_64_HHVM_SaveList;
+  case CallingConv::X86_RegCall:
+    if (Is64Bit) {
+      if (IsWin64) {
+        return (HasSSE ? CSR_Win64_RegCall_SaveList : 
+                         CSR_Win64_RegCall_NoSSE_SaveList);
+      } else {
+        return (HasSSE ? CSR_SysV64_RegCall_SaveList : 
+                         CSR_SysV64_RegCall_NoSSE_SaveList);
+      }
+    } else {
+      return (HasSSE ? CSR_32_RegCall_SaveList : 
+                       CSR_32_RegCall_NoSSE_SaveList);
+    }
   case CallingConv::Cold:
     if (Is64Bit)
       return CSR_64_MostRegs_SaveList;
@@ -406,6 +419,19 @@ X86RegisterInfo::getCallPreservedMask(const MachineFunction &MF,
   }
   case CallingConv::HHVM:
     return CSR_64_HHVM_RegMask;
+  case CallingConv::X86_RegCall:
+    if (Is64Bit) {
+      if (IsWin64) { 
+        return (HasSSE ? CSR_Win64_RegCall_RegMask : 
+                         CSR_Win64_RegCall_NoSSE_RegMask);
+      } else {
+        return (HasSSE ? CSR_SysV64_RegCall_RegMask : 
+                         CSR_SysV64_RegCall_NoSSE_RegMask);
+      }
+    } else {
+      return (HasSSE ? CSR_32_RegCall_RegMask : 
+                       CSR_32_RegCall_NoSSE_RegMask);
+    }
   case CallingConv::Cold:
     if (Is64Bit)
       return CSR_64_MostRegs_RegMask;