JIT: Add helpers for increasing/decreasing block weights (dotnet#111135)

Author: amanasifkhalid

src/coreclr/jit/block.h

@@ -1220,6 +1220,22 @@ struct BasicBlock : private LIR::Range
         }
     }
 
+    // increaseBBProfileWeight -- Increase the profile-derived weight for a basic block
+    // and update the run rarely flag as appropriate.
+    void increaseBBProfileWeight(weight_t weight)
+    {
+        assert(weight >= BB_ZERO_WEIGHT);
+        setBBProfileWeight(bbWeight + weight);
+    }
+
+    // decreaseBBProfileWeight -- Decrease the profile-derived weight for a basic block,
+    // ensuring it remains non-negative, and update the run rarely flag as appropriate.
+    void decreaseBBProfileWeight(weight_t weight)
+    {
+        assert(weight >= BB_ZERO_WEIGHT);
+        setBBProfileWeight(max(BB_ZERO_WEIGHT, bbWeight - weight));
+    }
+
     // this block will inherit the same weight and relevant bbFlags as bSrc
     //
     void inheritWeight(BasicBlock* bSrc)

src/coreclr/jit/compiler.h

@@ -6549,7 +6549,6 @@ class Compiler
 
 
     void WalkSpanningTree(SpanningTreeVisitor* visitor);
-    void fgSetProfileWeight(BasicBlock* block, weight_t weight);
     void fgApplyProfileScale();
     bool fgHaveSufficientProfileWeights();
     bool fgHaveTrustedProfileWeights();

src/coreclr/jit/fgehopt.cpp

@@ -671,7 +671,7 @@ PhaseStatus Compiler::fgRemoveEmptyTry()
         // Remove profile weight into the continuation block
         if (continuation->hasProfileWeight())
         {
-            continuation->setBBProfileWeight(max(0.0, continuation->bbWeight - leave->bbWeight));
+            continuation->decreaseBBProfileWeight(leave->bbWeight);
         }
 
         // (3) Convert the callfinally to a normal jump to the handler
@@ -717,7 +717,7 @@ PhaseStatus Compiler::fgRemoveEmptyTry()
                     // Propagate profile weight into the continuation block
                     if (continuation->hasProfileWeight())
                     {
-                        continuation->setBBProfileWeight(continuation->bbWeight + block->bbWeight);
+                        continuation->increaseBBProfileWeight(block->bbWeight);
                     }
                 }
             }
@@ -2208,16 +2208,12 @@ bool Compiler::fgRetargetBranchesToCanonicalCallFinally(BasicBlock*      block,
         //
         if (callFinally->hasProfileWeight())
         {
-            weight_t const newCallFinallyWeight =
-                callFinally->bbWeight > block->bbWeight ? callFinally->bbWeight - block->bbWeight : BB_ZERO_WEIGHT;
-            callFinally->setBBProfileWeight(newCallFinallyWeight);
+            callFinally->decreaseBBProfileWeight(block->bbWeight);
         }
 
         if (leaveBlock->hasProfileWeight())
         {
-            weight_t const newLeaveWeight =
-                leaveBlock->bbWeight > block->bbWeight ? leaveBlock->bbWeight - block->bbWeight : BB_ZERO_WEIGHT;
-            leaveBlock->setBBProfileWeight(newLeaveWeight);
+            leaveBlock->decreaseBBProfileWeight(block->bbWeight);
         }
     }
 

src/coreclr/jit/fgopt.cpp

@@ -655,7 +655,7 @@ PhaseStatus Compiler::fgPostImportationCleanup()
 
                         JITDUMP("Updating block weight for now-reachable try entry " FMT_BB " via " FMT_BB "\n",
                                 fromBlock->bbNum, fgFirstBB->bbNum);
-                        fromBlock->setBBProfileWeight(fromBlock->bbWeight + entryWeight);
+                        fromBlock->increaseBBProfileWeight(entryWeight);
 
                         // We updated the weight of fromBlock above.
                         //
@@ -2277,7 +2277,7 @@ bool Compiler::fgOptimizeUncondBranchToSimpleCond(BasicBlock* block, BasicBlock*
         //
         weight_t targetWeight = target->bbWeight;
         weight_t blockWeight  = block->bbWeight;
-        target->setBBProfileWeight(max(0.0, targetWeight - blockWeight));
+        target->decreaseBBProfileWeight(blockWeight);
         JITDUMP("Decreased " FMT_BB " profile weight from " FMT_WT " to " FMT_WT "\n", target->bbNum, targetWeight,
                 target->bbWeight);
     }
@@ -2944,11 +2944,10 @@ bool Compiler::fgOptimizeSwitchJumps()
 
         // Update profile data
         //
-        const weight_t fraction              = newBlock->GetSwitchTargets()->bbsDominantFraction;
-        const weight_t blockToTargetWeight   = block->bbWeight * fraction;
-        const weight_t blockToNewBlockWeight = block->bbWeight - blockToTargetWeight;
+        const weight_t fraction            = newBlock->GetSwitchTargets()->bbsDominantFraction;
+        const weight_t blockToTargetWeight = block->bbWeight * fraction;
 
-        newBlock->setBBProfileWeight(blockToNewBlockWeight);
+        newBlock->decreaseBBProfileWeight(blockToTargetWeight);
 
         blockToTargetEdge->setLikelihood(fraction);
         blockToNewBlockEdge->setLikelihood(max(0.0, 1.0 - fraction));

src/coreclr/jit/fgprofile.cpp

@@ -2963,21 +2963,6 @@ PhaseStatus Compiler::fgIncorporateProfileData()
     return PhaseStatus::MODIFIED_EVERYTHING;
 }
 
-//------------------------------------------------------------------------
-// fgSetProfileWeight: set profile weight for a block
-//
-// Arguments:
-//   block -- block in question
-//   profileWeight -- raw profile weight (not accounting for inlining)
-//
-// Notes:
-//   Does inlinee scaling.
-//
-void Compiler::fgSetProfileWeight(BasicBlock* block, weight_t profileWeight)
-{
-    block->setBBProfileWeight(profileWeight);
-}
-
 //------------------------------------------------------------------------
 // fgIncorporateBlockCounts: read block count based profile data
 //   and set block weights
@@ -3006,7 +2991,7 @@ bool Compiler::fgIncorporateBlockCounts()
 
         if (fgGetProfileWeightForBasicBlock(block->bbCodeOffs, &profileWeight))
         {
-            fgSetProfileWeight(block, profileWeight);
+            block->setBBProfileWeight(profileWeight);
         }
     }
 
@@ -3784,7 +3769,7 @@ void EfficientEdgeCountReconstructor::Propagate()
     {
         BlockInfo* const info = BlockToInfo(block);
         assert(info->m_weightKnown);
-        m_comp->fgSetProfileWeight(block, info->m_weight);
+        block->setBBProfileWeight(info->m_weight);
 
         const unsigned nSucc = block->NumSucc(m_comp);
         if (nSucc == 0)
@@ -5117,7 +5102,7 @@ void Compiler::fgRepairProfileCondToUncond(BasicBlock* block,
 
     if (target->hasProfileWeight())
     {
-        target->setBBProfileWeight(target->bbWeight + weight);
+        target->increaseBBProfileWeight(weight);
     }
     else
     {