[Mlir-commits] [mlir] c7592c7 - [mlir][scf] NFC - Add debug information to scf pipelining

[Nicolas Vasilache]

Author: Nicolas Vasilache
Date: 2023-05-30T01:02:51-07:00
New Revision: c7592c7714c2796715e6460fc5fd19e5a930c427

URL: https://github.com/llvm/llvm-project/commit/c7592c7714c2796715e6460fc5fd19e5a930c427
DIFF: https://github.com/llvm/llvm-project/commit/c7592c7714c2796715e6460fc5fd19e5a930c427.diff

LOG: [mlir][scf] NFC - Add debug information to scf pipelining

Added: 
    

Modified: 
    mlir/lib/Dialect/SCF/Transforms/LoopPipelining.cpp

Removed: 
    


################################################################################
diff  --git a/mlir/lib/Dialect/SCF/Transforms/LoopPipelining.cpp b/mlir/lib/Dialect/SCF/Transforms/LoopPipelining.cpp
index a85985b84a037..9b673d6f1de93 100644
--- a/mlir/lib/Dialect/SCF/Transforms/LoopPipelining.cpp
+++ b/mlir/lib/Dialect/SCF/Transforms/LoopPipelining.cpp
@@ -20,6 +20,11 @@
 #include "mlir/Support/MathExtras.h"
 #include "mlir/Transforms/RegionUtils.h"
 #include "llvm/ADT/MapVector.h"
+#include "llvm/Support/Debug.h"
+
+#define DEBUG_TYPE "scf-loop-pipelining"
+#define DBGS() (llvm::dbgs() << "[" DEBUG_TYPE "]: ")
+#define LDBG(X) LLVM_DEBUG(DBGS() << X << "\n")
 
 using namespace mlir;
 using namespace mlir::scf;
@@ -84,26 +89,33 @@ struct LoopPipelinerInternal {
 
 bool LoopPipelinerInternal::initializeLoopInfo(
     ForOp op, const PipeliningOption &options) {
+  LDBG("Start initializeLoopInfo");
   forOp = op;
   auto upperBoundCst =
       forOp.getUpperBound().getDefiningOp<arith::ConstantIndexOp>();
   auto lowerBoundCst =
       forOp.getLowerBound().getDefiningOp<arith::ConstantIndexOp>();
   auto stepCst = forOp.getStep().getDefiningOp<arith::ConstantIndexOp>();
-  if (!upperBoundCst || !lowerBoundCst || !stepCst)
+  if (!upperBoundCst || !lowerBoundCst || !stepCst) {
+    LDBG("--no constant bounds or step -> BAIL");
     return false;
+  }
   ub = upperBoundCst.value();
   lb = lowerBoundCst.value();
   step = stepCst.value();
   peelEpilogue = options.peelEpilogue;
   predicateFn = options.predicateFn;
-  if (!peelEpilogue && predicateFn == nullptr)
+  if (!peelEpilogue && predicateFn == nullptr) {
+    LDBG("--no epilogue or predicate set -> BAIL");
     return false;
+  }
   int64_t numIteration = ceilDiv(ub - lb, step);
   std::vector<std::pair<Operation *, unsigned>> schedule;
   options.getScheduleFn(forOp, schedule);
-  if (schedule.empty())
+  if (schedule.empty()) {
+    LDBG("--empty schedule -> BAIL");
     return false;
+  }
 
   opOrder.reserve(schedule.size());
   for (auto &opSchedule : schedule) {
@@ -111,13 +123,16 @@ bool LoopPipelinerInternal::initializeLoopInfo(
     stages[opSchedule.first] = opSchedule.second;
     opOrder.push_back(opSchedule.first);
   }
-  if (numIteration <= maxStage)
+  if (numIteration <= maxStage) {
+    LDBG("--fewer loop iterations than pipeline stages -> BAIL");
     return false;
+  }
 
   // All operations need to have a stage.
   for (Operation &op : forOp.getBody()->without_terminator()) {
     if (!stages.contains(&op)) {
       op.emitOpError("not assigned a pipeline stage");
+      LDBG("--op not assigned a pipeline stage: " << op << " -> BAIL");
       return false;
     }
   }
@@ -129,11 +144,15 @@ bool LoopPipelinerInternal::initializeLoopInfo(
     (void)stageNum;
     if (op == forOp.getBody()->getTerminator()) {
       op->emitError("terminator should not be assigned a stage");
+      LDBG("--terminator should not be assigned stage: " << *op << " -> BAIL");
       return false;
     }
     if (op->getBlock() != forOp.getBody()) {
       op->emitOpError("the owning Block of all operations assigned a stage "
                       "should be the loop body block");
+      LDBG("--the owning Block of all operations assigned a stage "
+           "should be the loop body block: "
+           << *op << " -> BAIL");
       return false;
     }
   }
@@ -145,8 +164,10 @@ bool LoopPipelinerInternal::initializeLoopInfo(
                    [this](Value operand) {
                      Operation *def = operand.getDefiningOp();
                      return !def || !stages.contains(def);
-                   }))
+                   })) {
+    LDBG("--only support loop carried dependency with a distance of 1 -> BAIL");
     return false;
+  }
   annotateFn = options.annotateFn;
   return true;
 }