[AMDGPU][IGLP]: Add SchedGroupMask::TRANS (#75416)

Makes constructing SchedGroups of this type easier, and provides ability
to create them with __builtin_amdgcn_sched_group_barrier

Author: jrbyrnes

llvm/docs/AMDGPUUsage.rst

@@ -1143,6 +1143,7 @@ The AMDGPU backend implements the following LLVM IR intrinsics.
                                                    - 0x0080: All DS instructions may be scheduled across sched_barrier.
                                                    - 0x0100: All DS read instructions may be scheduled accoss sched_barrier.
                                                    - 0x0200: All DS write instructions may be scheduled across sched_barrier.
+                                                   - 0x0400: All Transcendental (e.g. V_EXP) instructions may be scheduled across sched_barrier.
 
   llvm.amdgcn.sched_group_barrier                  Creates schedule groups with specific properties to create custom scheduling
                                                    pipelines. The ordering between groups is enforced by the instruction scheduler.

llvm/lib/Target/AMDGPU/AMDGPUIGroupLP.cpp

@@ -75,8 +75,9 @@ enum class SchedGroupMask {
   DS = 1u << 7,
   DS_READ = 1u << 8,
   DS_WRITE = 1u << 9,
+  TRANS = 1u << 10,
   ALL = ALU | VALU | SALU | MFMA | VMEM | VMEM_READ | VMEM_WRITE | DS |
-        DS_READ | DS_WRITE,
+        DS_READ | DS_WRITE | TRANS,
   LLVM_MARK_AS_BITMASK_ENUM(/* LargestFlag = */ ALL)
 };
 
@@ -1435,11 +1436,12 @@ bool SchedGroup::canAddMI(const MachineInstr &MI) const {
     Result = false;
 
   else if (((SGMask & SchedGroupMask::ALU) != SchedGroupMask::NONE) &&
-           (TII->isVALU(MI) || TII->isMFMAorWMMA(MI) || TII->isSALU(MI)))
+           (TII->isVALU(MI) || TII->isMFMAorWMMA(MI) || TII->isSALU(MI) ||
+            TII->isTRANS(MI)))
     Result = true;
 
   else if (((SGMask & SchedGroupMask::VALU) != SchedGroupMask::NONE) &&
-           TII->isVALU(MI) && !TII->isMFMAorWMMA(MI))
+           TII->isVALU(MI) && !TII->isMFMAorWMMA(MI) && !TII->isTRANS(MI))
     Result = true;
 
   else if (((SGMask & SchedGroupMask::SALU) != SchedGroupMask::NONE) &&
@@ -1476,6 +1478,10 @@ bool SchedGroup::canAddMI(const MachineInstr &MI) const {
            MI.mayStore() && TII->isDS(MI))
     Result = true;
 
+  else if (((SGMask & SchedGroupMask::TRANS) != SchedGroupMask::NONE) &&
+           TII->isTRANS(MI))
+    Result = true;
+
   LLVM_DEBUG(
       dbgs() << "For SchedGroup with mask " << format_hex((int)SGMask, 10, true)
              << (Result ? " could classify " : " unable to classify ") << MI);
@@ -1635,10 +1641,13 @@ void IGroupLPDAGMutation::addSchedBarrierEdges(SUnit &SchedBarrier) {
   // Remove all existing edges from the SCHED_BARRIER that were added due to the
   // instruction having side effects.
   resetEdges(SchedBarrier, DAG);
+  LLVM_DEBUG(dbgs() << "Building SchedGroup for SchedBarrier with Mask: "
+                    << MI.getOperand(0).getImm() << "\n");
   auto InvertedMask =
       invertSchedBarrierMask((SchedGroupMask)MI.getOperand(0).getImm());
   SchedGroup SG(InvertedMask, std::nullopt, DAG, TII);
   SG.initSchedGroup();
+
   // Preserve original instruction ordering relative to the SCHED_BARRIER.
   SG.link(
       SchedBarrier,
@@ -1652,14 +1661,15 @@ IGroupLPDAGMutation::invertSchedBarrierMask(SchedGroupMask Mask) const {
   // allowed past the SCHED_BARRIER.
   SchedGroupMask InvertedMask = ~Mask;
 
-  // ALU implies VALU, SALU, MFMA.
+  // ALU implies VALU, SALU, MFMA, TRANS.
   if ((InvertedMask & SchedGroupMask::ALU) == SchedGroupMask::NONE)
-    InvertedMask &=
-        ~SchedGroupMask::VALU & ~SchedGroupMask::SALU & ~SchedGroupMask::MFMA;
-  // VALU, SALU, MFMA implies ALU.
+    InvertedMask &= ~SchedGroupMask::VALU & ~SchedGroupMask::SALU &
+                    ~SchedGroupMask::MFMA & ~SchedGroupMask::TRANS;
+  // VALU, SALU, MFMA, TRANS implies ALU.
   else if ((InvertedMask & SchedGroupMask::VALU) == SchedGroupMask::NONE ||
            (InvertedMask & SchedGroupMask::SALU) == SchedGroupMask::NONE ||
-           (InvertedMask & SchedGroupMask::MFMA) == SchedGroupMask::NONE)
+           (InvertedMask & SchedGroupMask::MFMA) == SchedGroupMask::NONE ||
+           (InvertedMask & SchedGroupMask::TRANS) == SchedGroupMask::NONE)
     InvertedMask &= ~SchedGroupMask::ALU;
 
   // VMEM implies VMEM_READ, VMEM_WRITE.
@@ -1678,6 +1688,9 @@ IGroupLPDAGMutation::invertSchedBarrierMask(SchedGroupMask Mask) const {
            (InvertedMask & SchedGroupMask::DS_WRITE) == SchedGroupMask::NONE)
     InvertedMask &= ~SchedGroupMask::DS;
 
+  LLVM_DEBUG(dbgs() << "After Inverting, SchedGroup Mask: " << (int)InvertedMask
+                    << "\n");
+
   return InvertedMask;
 }