[mips] Add Mips-specific CCIf's for accessing the MipsCCState. NFC.

[vmedic]

LGTM

lib/Target/Mips/MipsCallingConv.td

: CCIf<!strconcat(Invert,
                       "static_cast<const MipsSubtarget&>"
       "(State.getMachineFunction().getSubtarget()).",
                       F),
            A>;
 
 // The inverse of CCIfSubtarget
 class CCIfSubtargetNot<string F, CCAction A> : CCIfSubtarget<F, A, "!">;
 
+/// Match if the original argument (before lowering) was a float.
+/// For example, this is true for i32's that were lowered from soft-float.
+class CCIfOrigArgWasNotFloat<CCAction A>
+    : CCIf<"!static_cast<MipsCCState *>(&State)->WasOriginalArgFloat(ValNo)",
+           A>;
+
+/// Match if the original argument (before lowering) was a 128-bit float (i.e.
+/// long double).
+class CCIfOrigArgWasF128<CCAction A>
+    : CCIf<"static_cast<MipsCCState *>(&State)->WasOriginalArgF128(ValNo)", A>;
+
+/// Match if this specific argument is a vararg.
+/// This is slightly different fro CCIfIsVarArg which matches if any argument is
+/// a vararg.
+class CCIfArgIsVarArg<CCAction A>
+    : CCIf<"!static_cast<MipsCCState *>(&State)->IsCallOperandFixed(ValNo)", A>;
+
+
+/// Match if the special calling conv is the specified value.
+class CCIfSpecialCallingConv<string CC, CCAction A>
+    : CCIf<"static_cast<MipsCCState *>(&State)->getSpecialCallingConv() == "
+               "MipsCCState::" # CC, A>;
+
 // For soft-float, f128 values are returned in A0_64 rather than V1_64.
 def RetCC_F128SoftFloat : CallingConv<[
   CCAssignToReg<[V0_64, A0_64]>
 ]>;
 
 // For hard-float, f128 values are returned as a pair of f64's rather than a
 // pair of i64's.
 def RetCC_F128HardFloat : CallingConv<[

 ]>;
 
 def CC_MipsN : CallingConv<[
   CCIfType<[i8, i16, i32],
       CCIfSubtargetNot<"isLittle()",
           CCIfInReg<CCPromoteToUpperBitsInType<i64>>>>,
 
   // All integers (except soft-float integers) are promoted to 64-bit.
-  CCIfType<[i8, i16, i32],
-     CCIf<"!static_cast<MipsCCState *>(&State)->WasOriginalArgFloat(ValNo)",
-          CCPromoteToType<i64>>>,
+  CCIfType<[i8, i16, i32], CCIfOrigArgWasNotFloat<CCPromoteToType<i64>>>,
 
   // The only i32's we have left are soft-float arguments.
   CCIfSubtarget<"abiUsesSoftFloat()", CCIfType<[i32], CCDelegateTo<CC_MipsN_SoftFloat>>>,
 
   // Integer arguments are passed in integer registers.
   CCIfType<[i64], CCAssignToRegWithShadow<[A0_64, A1_64, A2_64, A3_64,
                                            T0_64, T1_64, T2_64, T3_64],
                                           [D12_64, D13_64, D14_64, D15_64,
def RetCC_MipsN : CallingConv<[
   // This presents us with a problem for the calling convention since hard-float
   // still needs to pass them in FPU registers, and soft-float needs to use $v0,
   // and $a0 instead of the usual $v0, and $v1. We therefore resort to a
   // pre-analyze (see PreAnalyzeReturnForF128()) step to pass information on
   // whether the result was originally an f128 into the tablegen-erated code.
   //
   // f128 should only occur for the N64 ABI where long double is 128-bit. On
   // N32, long double is equivalent to double.
-  CCIfType<[i64],
-      CCIf<"static_cast<MipsCCState *>(&State)->WasOriginalArgF128(ValNo)",
-           CCDelegateTo<RetCC_F128>>>,
+  CCIfType<[i64], CCIfOrigArgWasF128<CCDelegateTo<RetCC_F128>>>,
 
   // Aggregate returns are positioned at the lowest address in the slot for
   // both little and big-endian targets. When passing in registers, this
   // requires that big-endian targets shift the value into the upper bits.
   CCIfSubtarget<"isLittle()",
       CCIfType<[i8, i16, i32, i64], CCIfInReg<CCPromoteToType<i64>>>>,
   CCIfSubtargetNot<"isLittle()",
       CCIfType<[i8, i16, i32, i64],
def CC_Mips16RetHelper : CallingConv<[
 
   // Integer arguments are passed in integer registers.
   CCIfType<[i32], CCAssignToReg<[V0, V1, A0, A1]>>
 ]>;
 
 def CC_Mips_FixedArg : CallingConv<[
   // Mips16 needs special handling on some functions.
   CCIf<"State.getCallingConv() != CallingConv::Fast",
-      CCIf<"static_cast<MipsCCState *>(&State)->getSpecialCallingConv() == "
-               "MipsCCState::Mips16RetHelperConv",
+      CCIfSpecialCallingConv<"Mips16RetHelperConv",
            CCDelegateTo<CC_Mips16RetHelper>>>,
 
   CCIfByVal<CCDelegateTo<CC_Mips_ByVal>>,
 
   // f128 needs to be handled similarly to f32 and f64 on hard-float. However,
   // f128 is not legal and is lowered to i128 which is further lowered to a pair
   // of i64's.
   // This presents us with a problem for the calling convention since hard-float
   // still needs to pass them in FPU registers. We therefore resort to a
   // pre-analyze (see PreAnalyzeFormalArgsForF128()) step to pass information on
   // whether the argument was originally an f128 into the tablegen-erated code.
   //
   // f128 should only occur for the N64 ABI where long double is 128-bit. On
   // N32, long double is equivalent to double.
   CCIfType<[i64],
       CCIfSubtargetNot<"abiUsesSoftFloat()",
-          CCIf<"static_cast<MipsCCState *>(&State)->WasOriginalArgF128(ValNo)",
-              CCBitConvertToType<f64>>>>,
+          CCIfOrigArgWasF128<CCBitConvertToType<f64>>>>,
 
   CCIfCC<"CallingConv::Fast", CCDelegateTo<CC_Mips_FastCC>>,
 
   // FIXME: There wasn't an EABI case in the original code and it seems unlikely
   //        that it's the same as CC_MipsN
   CCIfSubtarget<"isABI_O32()", CCDelegateTo<CC_MipsO32_FP>>,
   CCDelegateTo<CC_MipsN>
 ]>;
 
 def CC_Mips_VarArg : CallingConv<[
   CCIfByVal<CCDelegateTo<CC_Mips_ByVal>>,
 
   // FIXME: There wasn't an EABI case in the original code and it seems unlikely
   //        that it's the same as CC_MipsN_VarArg
   CCIfSubtarget<"isABI_O32()", CCDelegateTo<CC_MipsO32_FP>>,
   CCDelegateTo<CC_MipsN_VarArg>
 ]>;
 
 def CC_Mips : CallingConv<[
-  CCIfVarArg<
-      CCIf<"!static_cast<MipsCCState *>(&State)->IsCallOperandFixed(ValNo)",
-          CCDelegateTo<CC_Mips_VarArg>>>,
+  CCIfVarArg<CCIfArgIsVarArg<CCDelegateTo<CC_Mips_VarArg>>>,
   CCDelegateTo<CC_Mips_FixedArg>
 ]>;
 
 //===----------------------------------------------------------------------===//
 // Callee-saved register lists.
 //===----------------------------------------------------------------------===//
 
 def CSR_SingleFloatOnly : CalleeSavedRegs<(add (sequence "F%u", 31, 20), RA, FP,