JIT: Always aggressively compact blocks (#109521)

dotnet · Dec 5, 2024 · 052ad42 · 052ad42
1 parent 223dea5
commit 052ad42
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Showing 4 changed files with 8 additions and 14 deletions.
diff --git a/src/coreclr/jit/compiler.h b/src/coreclr/jit/compiler.h
@@ -6286,7 +6286,7 @@ class Compiler
 
     bool fgIsForwardBranch(BasicBlock* bJump, BasicBlock* bDest, BasicBlock* bSrc = nullptr);
 
-    bool fgUpdateFlowGraph(bool doTailDup = false, bool isPhase = false, bool doAggressiveCompaction = true);
+    bool fgUpdateFlowGraph(bool doTailDup = false, bool isPhase = false);
     PhaseStatus fgUpdateFlowGraphPhase();
 
     PhaseStatus fgDfsBlocksAndRemove();
@@ -6354,7 +6354,7 @@ class Compiler
 
     static fgWalkPreFn fgStress64RsltMulCB;
     void               fgStress64RsltMul();
-    void               fgDebugCheckUpdate(const bool doAggressiveCompaction);
+    void               fgDebugCheckUpdate();
 
     void fgDebugCheckBBNumIncreasing();
     void fgDebugCheckBBlist(bool checkBBNum = false, bool checkBBRefs = true);

diff --git a/src/coreclr/jit/fgdiagnostic.cpp b/src/coreclr/jit/fgdiagnostic.cpp
@@ -56,7 +56,7 @@ void Compiler::fgPrintEdgeWeights()
 
 #ifdef DEBUG
 
-void Compiler::fgDebugCheckUpdate(const bool doAggressiveCompaction)
+void Compiler::fgDebugCheckUpdate()
 {
     if (!compStressCompile(STRESS_CHK_FLOW_UPDATE, 30))
     {
@@ -139,7 +139,7 @@ void Compiler::fgDebugCheckUpdate(const bool doAggressiveCompaction)
 
         /* no un-compacted blocks */
 
-        if (fgCanCompactBlock(block) && (doAggressiveCompaction || block->JumpsToNext()))
+        if (fgCanCompactBlock(block))
         {
             noway_assert(!"Found un-compacted blocks!");
         }

diff --git a/src/coreclr/jit/fgopt.cpp b/src/coreclr/jit/fgopt.cpp
@@ -5586,18 +5586,14 @@ PhaseStatus Compiler::fgUpdateFlowGraphPhase()
 // Arguments:
 //    doTailDuplication - true to attempt tail duplication optimization
 //    isPhase - true if being run as the only thing in a phase
-//    doAggressiveCompaction - if false, only compact blocks that jump to the next block
-//    to prevent modifying the flowgraph; else, compact as much as possible
 //
 // Returns: true if the flowgraph has been modified
 //
 // Notes:
 //    Debuggable code and Min Optimization JIT also introduces basic blocks
 //    but we do not optimize those!
 //
-bool Compiler::fgUpdateFlowGraph(bool doTailDuplication /* = false */,
-                                 bool isPhase /* = false */,
-                                 bool doAggressiveCompaction /* = true */)
+bool Compiler::fgUpdateFlowGraph(bool doTailDuplication /* = false */, bool isPhase /* = false */)
 {
 #ifdef DEBUG
     if (verbose && !isPhase)
@@ -5981,7 +5977,7 @@ bool Compiler::fgUpdateFlowGraph(bool doTailDuplication /* = false */,
 
             /* COMPACT blocks if possible */
 
-            if (fgCanCompactBlock(block) && (doAggressiveCompaction || block->JumpsToNext()))
+            if (fgCanCompactBlock(block))
             {
                 fgCompactBlock(block);
 
@@ -6115,7 +6111,7 @@ bool Compiler::fgUpdateFlowGraph(bool doTailDuplication /* = false */,
         fgVerifyHandlerTab();
         // Make sure that the predecessor lists are accurate
         fgDebugCheckBBlist();
-        fgDebugCheckUpdate(doAggressiveCompaction);
+        fgDebugCheckUpdate();
     }
 #endif // DEBUG
 

diff --git a/src/coreclr/jit/lower.cpp b/src/coreclr/jit/lower.cpp
@@ -7885,9 +7885,7 @@ PhaseStatus Lowering::DoPhase()
 
         comp->fgLocalVarLiveness();
         // local var liveness can delete code, which may create empty blocks
-        // Don't churn the flowgraph with aggressive compaction since we've already run block layout
-        bool modified = comp->fgUpdateFlowGraph(/* doTailDuplication */ false, /* isPhase */ false,
-                                                /* doAggressiveCompaction */ false);
+        bool modified = comp->fgUpdateFlowGraph(/* doTailDuplication */ false, /* isPhase */ false);
 
         if (modified)
         {