Several changes to Mips backend, experimental fp support being the most
important.
- Cleanup in the Subtarget info with addition of new features, not all support
  yet, but they allow the future inclusion of features easier. Among new features,
  we have : Arch family info (mips1, mips2, ...), ABI info (o32, eabi), 64-bit
  integer
  and float registers, allegrex vector FPU (VFPU), single float only support.
- TargetMachine now detects allegrex core.
- Added allegrex (Mips32r2) sext_inreg instructions.
- *Added Float Point Instructions*, handling single float only, and
  aliased accesses for 32-bit FPUs.
- Some cleanup in FP instruction formats and FP register classes.
- Calling conventions improved to support mips 32-bit EABI.
- Added Asm Printer support for fp cond codes.
- Added support for sret copy to a return register.
- EABI support added into LowerCALL and FORMAL_ARGS.
- MipsFunctionInfo now keeps a virtual register per function to track the
  sret on function entry until function ret.
- MipsInstrInfo FP support into methods (isMoveInstr, isLoadFromStackSlot, ...),
  FP cond codes mapping and initial FP Branch Analysis.
- Two new Mips SDNode to handle fp branch and compare instructions : FPBrcond,
  FPCmp
- MipsTargetLowering : handling different FP classes, Allegrex support, sret
  return copy, no homing location within EABI, non 32-bit stack objects
  arguments, and asm constraint for float.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53146 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsCallingConv.td b/lib/Target/Mips/MipsCallingConv.td
index 85f019d..c05e82d 100644
--- a/lib/Target/Mips/MipsCallingConv.td
+++ b/lib/Target/Mips/MipsCallingConv.td
@@ -14,18 +14,9 @@
   CCIf<!strconcat("State.getTarget().getSubtarget<MipsSubtarget>().", F), A>;
 
 //===----------------------------------------------------------------------===//
-// Mips Return Value Calling Convention
+// Mips O32 Calling Convention
 //===----------------------------------------------------------------------===//
-def RetCC_Mips : CallingConv<[
-  // i32 are returned in registers V0, V1
-  CCIfType<[i32], CCAssignToReg<[V0, V1]>>
-]>;
-
-
-//===----------------------------------------------------------------------===//
-// Mips Argument Calling Conventions
-//===----------------------------------------------------------------------===//
-def CC_Mips : CallingConv<[
+def CC_MipsO32 : CallingConv<[
   // Promote i8/i16 arguments to i32.
   CCIfType<[i8, i16], CCPromoteToType<i32>>,
 
@@ -37,3 +28,62 @@
   CCIfType<[i32], CCAssignToStack<4, 4>>
 ]>;
 
+def RetCC_MipsO32 : CallingConv<[
+  // i32 are returned in registers V0, V1
+  CCIfType<[i32], CCAssignToReg<[V0, V1]>>
+]>;
+
+//===----------------------------------------------------------------------===//
+// Mips EABI Calling Convention
+//===----------------------------------------------------------------------===//
+def CC_MipsEABI : CallingConv<[
+  // Promote i8/i16 arguments to i32.
+  CCIfType<[i8, i16], CCPromoteToType<i32>>,
+
+  // Integer arguments are passed in integer registers.
+  CCIfType<[i32], CCAssignToReg<[A0, A1, A2, A3, T0, T1, T2, T3]>>,
+
+  // Single fp arguments are passed in pairs within 32-bit mode 
+  CCIfType<[f32], CCIfSubtarget<"isSingleFloat()", 
+                  CCAssignToReg<[F12, F13, F14, F15, F16, F17, F18, F19]>>>,
+
+  CCIfType<[f32], CCIfSubtarget<"isNotSingleFloat()", 
+                  CCAssignToReg<[F12, F14, F16, F18]>>>,
+
+  // The first 4 doubl fp arguments are passed in single fp registers.
+  CCIfType<[f64], CCIfSubtarget<"isNotSingleFloat()", 
+                  CCAssignToReg<[D6, D7, D8, D9]>>>,
+
+  // Integer values get stored in stack slots that are 4 bytes in
+  // size and 4-byte aligned.
+  CCIfType<[i32, f32], CCAssignToStack<4, 4>>,
+
+  // Integer values get stored in stack slots that are 8 bytes in
+  // size and 8-byte aligned.
+  CCIfType<[f64], CCIfSubtarget<"isNotSingleFloat()", CCAssignToStack<8, 8>>>
+]>;
+
+def RetCC_MipsEABI : CallingConv<[
+  // i32 are returned in registers V0, V1
+  CCIfType<[i32], CCAssignToReg<[V0, V1]>>,
+
+  // f32 are returned in registers F0, F1
+  CCIfType<[f32], CCAssignToReg<[F0, F1]>>,
+
+  // f64 are returned in register D0
+  CCIfType<[f64], CCIfSubtarget<"isNotSingleFloat()", CCAssignToReg<[D0]>>>
+]>;
+
+//===----------------------------------------------------------------------===//
+// Mips Calling Convention Dispatch
+//===----------------------------------------------------------------------===//
+
+def CC_Mips : CallingConv<[
+  CCIfSubtarget<"isABI_EABI()", CCDelegateTo<CC_MipsEABI>>,
+  CCDelegateTo<CC_MipsO32>
+]>;
+
+def RetCC_Mips : CallingConv<[
+  CCIfSubtarget<"isABI_EABI()", CCDelegateTo<RetCC_MipsEABI>>,
+  CCDelegateTo<RetCC_MipsO32>
+]>;