no merge

src/coreclr/jit/block.cpp

@@ -297,7 +297,7 @@ bool BasicBlock::IsFirstColdBlock(Compiler* compiler) const
 bool BasicBlock::CanRemoveJumpToNext(Compiler* compiler) const
 {
     assert(KindIs(BBJ_ALWAYS));
-    return JumpsToNext() && (bbNext != compiler->fgFirstColdBlock);
+    return JumpsToNext() && (bbNext != compiler->fgFirstColdBlock) && (!hasAlign() || HasFlag(BBF_JMP_TO_NESTED_LOOP));
 }
 
 //------------------------------------------------------------------------

src/coreclr/jit/block.h

@@ -429,6 +429,7 @@ enum BasicBlockFlags : unsigned __int64
                                                           // (TODO: Remove this quirk after refactoring Compiler::fgFindInsertPoint)
     BBF_OLD_LOOP_HEADER_QUIRK          = MAKE_BBFLAG(42), // Block was the header ('entry') of a loop recognized by old loop finding
     BBF_HAS_VALUE_PROFILE              = MAKE_BBFLAG(43), // Block has a node that needs a value probing
+    BBF_JMP_TO_NESTED_LOOP             = MAKE_BBFLAG(44),
 
     // The following are sets of flags.
 

src/coreclr/jit/compiler.cpp

@@ -5431,6 +5431,13 @@ PhaseStatus Compiler::placeLoopAlignInstructions()
                 bbHavingAlign = prev;
                 JITDUMP("Marking " FMT_BB " before the loop with BBF_HAS_ALIGN for loop at " FMT_BB "\n", prev->bbNum,
                         block->bbNum);
+
+                // bbHavingAlign is in a loop, and precedes a nested loop
+                if (blockToLoop->GetLoop(bbHavingAlign) != nullptr)
+                {
+                    // If bbHavingAlign is a removable jump, it will be removed despite it having alignment
+                    bbHavingAlign->SetFlags(BBF_JMP_TO_NESTED_LOOP);
+                }
             }
             else
             {

src/coreclr/scripts/superpmi.py

@@ -1971,7 +1971,7 @@ def replay_with_asm_diffs(self):
 
         # These vars are force overridden in the SPMI runs for both the base and diff, always.
         replay_vars = {
-            "DOTNET_JitAlignLoops": "0", # disable loop alignment to filter noise
+            "DOTNET_JitAlignLoops": "1", # disable loop alignment to filter noise
             "DOTNET_JitEnableNoWayAssert": "1",
             "DOTNET_JitNoForceFallback": "1",
         }