JIT: Make loop inversion graph based

src/coreclr/jit/compiler.cpp

@@ -4825,10 +4825,6 @@ void Compiler::compCompile(void** methodCodePtr, uint32_t* methodCodeSize, JitFl
         //
         DoPhase(this, PHASE_COMPUTE_BLOCK_WEIGHTS, &Compiler::fgComputeBlockWeights);
 
-        // Invert loops
-        //
-        DoPhase(this, PHASE_INVERT_LOOPS, &Compiler::optInvertLoops);
-
         // Run some flow graph optimizations (but don't reorder)
         //
         DoPhase(this, PHASE_OPTIMIZE_FLOW, &Compiler::optOptimizeFlow);
@@ -4852,6 +4848,10 @@ void Compiler::compCompile(void** methodCodePtr, uint32_t* methodCodeSize, JitFl
         //
         DoPhase(this, PHASE_SET_BLOCK_WEIGHTS, &Compiler::optSetBlockWeights);
 
+        // Invert loops
+        //
+        DoPhase(this, PHASE_INVERT_LOOPS, &Compiler::optInvertLoops);
+
         // Clone loops with optimization opportunities, and choose one based on dynamic condition evaluation.
         //
         DoPhase(this, PHASE_CLONE_LOOPS, &Compiler::optCloneLoops);

src/coreclr/jit/compiler.h

@@ -7196,7 +7196,7 @@ class Compiler
 
     OptInvertCountTreeInfoType optInvertCountTreeInfo(GenTree* tree);
 
-    bool optInvertWhileLoop(BasicBlock* block);
+    bool optTryInvertWhileLoop(FlowGraphNaturalLoop* loop);
     bool optIfConvert(BasicBlock* block);
 
 private:

src/coreclr/jit/fgdiagnostic.cpp

@@ -4708,7 +4708,12 @@ void Compiler::fgDebugCheckLoops()
             loop->VisitRegularExitBlocks([=](BasicBlock* exit) {
                 for (BasicBlock* pred : exit->PredBlocks())
                 {
-                    assert(loop->ContainsBlock(pred));
+                    if (!loop->ContainsBlock(pred))
+                    {
+                        JITDUMP("Loop " FMT_LP " exit " FMT_BB " has non-loop predecessor " FMT_BB "\n",
+                                loop->GetIndex(), exit->bbNum, pred->bbNum);
+                        assert(!"Loop exit has non-loop predecessor");
+                    }
                 }
                 return BasicBlockVisit::Continue;
             });