[PowerPC] Support constrained fp operation for setcc

The constrained fp operation fcmp was added by https://reviews.llvm.org/D69281.
This patch is trying to add the support for PowerPC backend.

Reviewed By: uweigand

Differential Revision: https://reviews.llvm.org/D81727

Author: QingShan Zhang

llvm/include/llvm/Target/TargetSelectionDAG.td

@@ -553,6 +553,8 @@ def strict_sint_to_fp : SDNode<"ISD::STRICT_SINT_TO_FP",
                                SDTIntToFPOp, [SDNPHasChain]>;
 def strict_uint_to_fp : SDNode<"ISD::STRICT_UINT_TO_FP",
                                SDTIntToFPOp, [SDNPHasChain]>;
+def strict_fsetcc  : SDNode<"ISD::STRICT_FSETCC",  SDTSetCC, [SDNPHasChain]>;
+def strict_fsetccs : SDNode<"ISD::STRICT_FSETCCS", SDTSetCC, [SDNPHasChain]>;
 
 def setcc      : SDNode<"ISD::SETCC"      , SDTSetCC>;
 def select     : SDNode<"ISD::SELECT"     , SDTSelect>;
@@ -1420,6 +1422,12 @@ def any_sint_to_fp : PatFrags<(ops node:$src),
 def any_uint_to_fp : PatFrags<(ops node:$src),
                               [(strict_uint_to_fp node:$src),
                                (uint_to_fp node:$src)]>;
+def any_fsetcc : PatFrags<(ops node:$lhs, node:$rhs, node:$pred),
+                          [(strict_fsetcc node:$lhs, node:$rhs, node:$pred),
+                           (setcc node:$lhs, node:$rhs, node:$pred)]>;
+def any_fsetccs : PatFrags<(ops node:$lhs, node:$rhs, node:$pred),
+                          [(strict_fsetccs node:$lhs, node:$rhs, node:$pred),
+                           (setcc node:$lhs, node:$rhs, node:$pred)]>;
 
 multiclass binary_atomic_op_ord<SDNode atomic_op> {
   def NAME#_monotonic : PatFrag<(ops node:$ptr, node:$val),

llvm/lib/Target/PowerPC/P9InstrResources.td

@@ -94,7 +94,7 @@ def : InstRW<[P9_ALU_3C, IP_EXEC_1C, DISP_3SLOTS_1C],
     (instregex "CMPRB(8)?$"),
     (instregex "TD(I)?$"),
     (instregex "TW(I)?$"),
-    (instregex "FCMPU(S|D)$"),
+    (instregex "FCMP(O|U)(S|D)$"),
     (instregex "XSTSTDC(S|D)P$"),
     FTDIV,
     FTSQRT,

llvm/lib/Target/PowerPC/PPCISelLowering.cpp

@@ -419,6 +419,16 @@ PPCTargetLowering::PPCTargetLowering(const PPCTargetMachine &TM,
   if (!Subtarget.useCRBits())
     setOperationAction(ISD::SETCC, MVT::i32, Custom);
 
+  if (Subtarget.hasFPU()) {
+    setOperationAction(ISD::STRICT_FSETCC, MVT::f32, Legal);
+    setOperationAction(ISD::STRICT_FSETCC, MVT::f64, Legal);
+    setOperationAction(ISD::STRICT_FSETCC, MVT::f128, Legal);
+
+    setOperationAction(ISD::STRICT_FSETCCS, MVT::f32, Legal);
+    setOperationAction(ISD::STRICT_FSETCCS, MVT::f64, Legal);
+    setOperationAction(ISD::STRICT_FSETCCS, MVT::f128, Legal);
+  }
+
   // PowerPC does not have BRCOND which requires SetCC
   if (!Subtarget.useCRBits())
     setOperationAction(ISD::BRCOND, MVT::Other, Expand);

llvm/lib/Target/PowerPC/PPCInstrInfo.td

@@ -2570,14 +2570,17 @@ let isCompare = 1, hasSideEffects = 0 in {
 }
 }
 let PPC970_Unit = 3, Predicates = [HasFPU] in {  // FPU Operations.
-//def FCMPO  : XForm_17<63, 32, (outs CRRC:$crD), (ins FPRC:$fA, FPRC:$fB),
-//                      "fcmpo $crD, $fA, $fB", IIC_FPCompare>;
 let isCompare = 1, hasSideEffects = 0 in {
   def FCMPUS : XForm_17<63, 0, (outs crrc:$crD), (ins f4rc:$fA, f4rc:$fB),
                         "fcmpu $crD, $fA, $fB", IIC_FPCompare>;
-  let Interpretation64Bit = 1, isCodeGenOnly = 1 in
-  def FCMPUD : XForm_17<63, 0, (outs crrc:$crD), (ins f8rc:$fA, f8rc:$fB),
-                        "fcmpu $crD, $fA, $fB", IIC_FPCompare>;
+  def FCMPOS : XForm_17<63, 32, (outs crrc:$crD), (ins f4rc:$fA, f4rc:$fB),
+                        "fcmpo $crD, $fA, $fB", IIC_FPCompare>;
+  let Interpretation64Bit = 1, isCodeGenOnly = 1 in {
+    def FCMPUD : XForm_17<63, 0, (outs crrc:$crD), (ins f8rc:$fA, f8rc:$fB),
+                          "fcmpu $crD, $fA, $fB", IIC_FPCompare>;
+    def FCMPOD : XForm_17<63, 32, (outs crrc:$crD), (ins f8rc:$fA, f8rc:$fB),
+                          "fcmpo $crD, $fA, $fB", IIC_FPCompare>;
+  }
 }
 
 def FTDIV: XForm_17<63, 128, (outs crrc:$crD), (ins f8rc:$fA, f8rc:$fB),
@@ -3934,14 +3937,27 @@ multiclass FSetCCPat<SDNode SetCC, ValueType Ty, PatLeaf FCmp> {
 }
 
 let Predicates = [HasFPU] in {
+// FCMPU: If either of the operands is a Signaling NaN, then VXSNAN is set.
 // SETCC for f32.
-defm : FSetCCPat<setcc, f32, FCMPUS>;
+defm : FSetCCPat<any_fsetcc, f32, FCMPUS>;
 
 // SETCC for f64.
-defm : FSetCCPat<setcc, f64, FCMPUD>;
+defm : FSetCCPat<any_fsetcc, f64, FCMPUD>;
 
 // SETCC for f128.
-defm : FSetCCPat<setcc, f128, XSCMPUQP>;
+defm : FSetCCPat<any_fsetcc, f128, XSCMPUQP>;
+
+// FCMPO: If either of the operands is a Signaling NaN, then VXSNAN is set and,
+// if neither operand is a Signaling NaN but at least one operand is a Quiet NaN,
+// then VXVC is set.
+// SETCCS for f32.
+defm : FSetCCPat<strict_fsetccs, f32, FCMPOS>;
+
+// SETCCS for f64.
+defm : FSetCCPat<strict_fsetccs, f64, FCMPOD>;
+
+// SETCCS for f128.
+defm : FSetCCPat<strict_fsetccs, f128, XSCMPOQP>;
 }
 
 // This must be in this file because it relies on patterns defined in this file