DAG: Move soft float predicate management into RuntimeLibcalls (llvm#142905)

Work towards making RuntimeLibcalls the centralized location for
all libcall information. This requires changing the encoding from
tracking the ISD::CondCode to using CmpInst::Predicate.

Author: arsenm

llvm/include/llvm/CodeGen/TargetLowering.h

@@ -3574,20 +3574,18 @@ class LLVM_ABI TargetLoweringBase {
 
   /// Override the default CondCode to be used to test the result of the
   /// comparison libcall against zero.
-  /// FIXME: This can't be merged with 'RuntimeLibcallsInfo' because of the ISD.
-  void setCmpLibcallCC(RTLIB::Libcall Call, ISD::CondCode CC) {
-    CmpLibcallCCs[Call] = CC;
+  /// FIXME: This should be removed
+  void setCmpLibcallCC(RTLIB::Libcall Call, CmpInst::Predicate Pred) {
+    Libcalls.setSoftFloatCmpLibcallPredicate(Call, Pred);
   }
 
-
   /// Get the CondCode that's to be used to test the result of the comparison
   /// libcall against zero.
-  /// FIXME: This can't be merged with 'RuntimeLibcallsInfo' because of the ISD.
-  ISD::CondCode getCmpLibcallCC(RTLIB::Libcall Call) const {
-    return CmpLibcallCCs[Call];
+  CmpInst::Predicate
+  getSoftFloatCmpLibcallPredicate(RTLIB::Libcall Call) const {
+    return Libcalls.getSoftFloatCmpLibcallPredicate(Call);
   }
 
-
   /// Set the CallingConv that should be used for the specified libcall.
   void setLibcallCallingConv(RTLIB::Libcall Call, CallingConv::ID CC) {
     Libcalls.setLibcallCallingConv(Call, CC);

llvm/include/llvm/IR/RuntimeLibcalls.h

@@ -17,6 +17,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/Sequence.h"
 #include "llvm/IR/CallingConv.h"
+#include "llvm/IR/InstrTypes.h"
 #include "llvm/Support/AtomicOrdering.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/TargetParser/Triple.h"
@@ -86,13 +87,35 @@ struct RuntimeLibcallsInfo {
     return ArrayRef(LibcallRoutineNames).drop_back();
   }
 
+  /// Get the comparison predicate that's to be used to test the result of the
+  /// comparison libcall against zero. This should only be used with
+  /// floating-point compare libcalls.
+  CmpInst::Predicate
+  getSoftFloatCmpLibcallPredicate(RTLIB::Libcall Call) const {
+    return SoftFloatCompareLibcallPredicates[Call];
+  }
+
+  // FIXME: This should be removed. This should be private constant.
+  void setSoftFloatCmpLibcallPredicate(RTLIB::Libcall Call,
+                                       CmpInst::Predicate Pred) {
+    SoftFloatCompareLibcallPredicates[Call] = Pred;
+  }
+
 private:
   /// Stores the name each libcall.
   const char *LibcallRoutineNames[RTLIB::UNKNOWN_LIBCALL + 1];
 
   /// Stores the CallingConv that should be used for each libcall.
   CallingConv::ID LibcallCallingConvs[RTLIB::UNKNOWN_LIBCALL];
 
+  /// The condition type that should be used to test the result of each of the
+  /// soft floating-point comparison libcall against integer zero.
+  ///
+  // FIXME: This is only relevant for the handful of floating-point comparison
+  // runtime calls; it's excessive to have a table entry for every single
+  // opcode.
+  CmpInst::Predicate SoftFloatCompareLibcallPredicates[RTLIB::UNKNOWN_LIBCALL];
+
   static bool darwinHasSinCos(const Triple &TT) {
     assert(TT.isOSDarwin() && "should be called with darwin triple");
     // Don't bother with 32 bit x86.
@@ -108,6 +131,8 @@ struct RuntimeLibcallsInfo {
     return true;
   }
 
+  void initSoftFloatCmpLibcallPredicates();
+
   /// Set default libcall names. If a target wants to opt-out of a libcall it
   /// should be placed here.
   LLVM_ABI void initLibcalls(const Triple &TT);

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -14,6 +14,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/Analysis/VectorUtils.h"
+#include "llvm/CodeGen/Analysis.h"
 #include "llvm/CodeGen/CallingConvLower.h"
 #include "llvm/CodeGen/CodeGenCommonISel.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
@@ -419,7 +420,7 @@ void TargetLowering::softenSetCCOperands(SelectionDAG &DAG, EVT VT,
   NewLHS = Call.first;
   NewRHS = DAG.getConstant(0, dl, RetVT);
 
-  CCCode = getCmpLibcallCC(LC1);
+  CCCode = getICmpCondCode(getSoftFloatCmpLibcallPredicate(LC1));
   if (ShouldInvertCC) {
     assert(RetVT.isInteger());
     CCCode = getSetCCInverse(CCCode, RetVT);
@@ -441,7 +442,7 @@ void TargetLowering::softenSetCCOperands(SelectionDAG &DAG, EVT VT,
 
     SDValue Tmp = DAG.getSetCC(dl, SetCCVT, NewLHS, NewRHS, CCCode);
     auto Call2 = makeLibCall(DAG, LC2, RetVT, Ops, CallOptions, dl, Chain);
-    CCCode = getCmpLibcallCC(LC2);
+    CCCode = getICmpCondCode(getSoftFloatCmpLibcallPredicate(LC2));
     if (ShouldInvertCC)
       CCCode = getSetCCInverse(CCCode, RetVT);
     NewLHS = DAG.getSetCC(dl, SetCCVT, Call2.first, NewRHS, CCCode);

llvm/lib/IR/RuntimeLibcalls.cpp

@@ -220,12 +220,45 @@ static void setMSP430Libcalls(RuntimeLibcallsInfo &Info, const Triple &TT) {
   // TODO: __mspabi_srall, __mspabi_srlll, __mspabi_sllll
 }
 
+void RuntimeLibcallsInfo::initSoftFloatCmpLibcallPredicates() {
+  SoftFloatCompareLibcallPredicates[RTLIB::OEQ_F32] = CmpInst::ICMP_EQ;
+  SoftFloatCompareLibcallPredicates[RTLIB::OEQ_F64] = CmpInst::ICMP_EQ;
+  SoftFloatCompareLibcallPredicates[RTLIB::OEQ_F128] = CmpInst::ICMP_EQ;
+  SoftFloatCompareLibcallPredicates[RTLIB::OEQ_PPCF128] = CmpInst::ICMP_EQ;
+  SoftFloatCompareLibcallPredicates[RTLIB::UNE_F32] = CmpInst::ICMP_NE;
+  SoftFloatCompareLibcallPredicates[RTLIB::UNE_F64] = CmpInst::ICMP_NE;
+  SoftFloatCompareLibcallPredicates[RTLIB::UNE_F128] = CmpInst::ICMP_NE;
+  SoftFloatCompareLibcallPredicates[RTLIB::UNE_PPCF128] = CmpInst::ICMP_NE;
+  SoftFloatCompareLibcallPredicates[RTLIB::OGE_F32] = CmpInst::ICMP_SGE;
+  SoftFloatCompareLibcallPredicates[RTLIB::OGE_F64] = CmpInst::ICMP_SGE;
+  SoftFloatCompareLibcallPredicates[RTLIB::OGE_F128] = CmpInst::ICMP_SGE;
+  SoftFloatCompareLibcallPredicates[RTLIB::OGE_PPCF128] = CmpInst::ICMP_SGE;
+  SoftFloatCompareLibcallPredicates[RTLIB::OLT_F32] = CmpInst::ICMP_SLT;
+  SoftFloatCompareLibcallPredicates[RTLIB::OLT_F64] = CmpInst::ICMP_SLT;
+  SoftFloatCompareLibcallPredicates[RTLIB::OLT_F128] = CmpInst::ICMP_SLT;
+  SoftFloatCompareLibcallPredicates[RTLIB::OLT_PPCF128] = CmpInst::ICMP_SLT;
+  SoftFloatCompareLibcallPredicates[RTLIB::OLE_F32] = CmpInst::ICMP_SLE;
+  SoftFloatCompareLibcallPredicates[RTLIB::OLE_F64] = CmpInst::ICMP_SLE;
+  SoftFloatCompareLibcallPredicates[RTLIB::OLE_F128] = CmpInst::ICMP_SLE;
+  SoftFloatCompareLibcallPredicates[RTLIB::OLE_PPCF128] = CmpInst::ICMP_SLE;
+  SoftFloatCompareLibcallPredicates[RTLIB::OGT_F32] = CmpInst::ICMP_SGT;
+  SoftFloatCompareLibcallPredicates[RTLIB::OGT_F64] = CmpInst::ICMP_SGT;
+  SoftFloatCompareLibcallPredicates[RTLIB::OGT_F128] = CmpInst::ICMP_SGT;
+  SoftFloatCompareLibcallPredicates[RTLIB::OGT_PPCF128] = CmpInst::ICMP_SGT;
+  SoftFloatCompareLibcallPredicates[RTLIB::UO_F32] = CmpInst::ICMP_NE;
+  SoftFloatCompareLibcallPredicates[RTLIB::UO_F64] = CmpInst::ICMP_NE;
+  SoftFloatCompareLibcallPredicates[RTLIB::UO_F128] = CmpInst::ICMP_NE;
+  SoftFloatCompareLibcallPredicates[RTLIB::UO_PPCF128] = CmpInst::ICMP_NE;
+}
+
 /// Set default libcall names. If a target wants to opt-out of a libcall it
 /// should be placed here.
 void RuntimeLibcallsInfo::initLibcalls(const Triple &TT) {
   std::fill(std::begin(LibcallRoutineNames), std::end(LibcallRoutineNames),
             nullptr);
 
+  initSoftFloatCmpLibcallPredicates();
+
 #define HANDLE_LIBCALL(code, name) setLibcallName(RTLIB::code, name);
 #define LIBCALL_NO_NAME nullptr
 #include "llvm/IR/RuntimeLibcalls.def"