JIT: loop inversion doing some questionable profile maintenance #84319
Description
From the PerfLabTests.CastingPerf:CheckArrayIsInterfaceNo benchmark, running with TieredPGO, during an OSR recompile:
Note how BB04's profile data gets trashed
****** START compiling PerfLabTests.CastingPerf:CheckArrayIsInterfaceNo():bool:this (MethodHash=a46d9cd6)
Generating code for Windows x64
OPTIONS: Tier-1 compilation
OPTIONS: OSR variant with entry point 0x18
...
*************** Starting PHASE Invert loops
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BBnum BBid ref try hnd preds weight IBC lp [IL range] [jump] [EH region] [flags]
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BB01 [0004] 1 1 48701 [???..???)-> BB04 (always) i internal IBC
BB02 [0000] 0 0.00 1 [000..006)-> BB04 (always) i IBC
BB03 [0001] 1 BB04 100.00 4870143 [006..018) i hascall bwd bwd-target IBC
BB04 [0002] 3 BB01,BB02,BB03 100 4870144 [018..020)-> BB03 ( cond ) i bwd bwd-src IBC osr-entry
BB05 [0003] 1 BB04 0 0 [020..022) (return) i rare IBC
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*************** Exception Handling table is empty
=============== No blocks renumbered!
Duplication of loop condition [000010] is performed, because the cost of duplication (17) is less or equal than 136,
loopIterations = 4870143.000, optInvertTotalInfo.sharedStaticHelperCount >= 0, validProfileWeights = true
New Basic Block BB06 [0005] created.
Setting edge weights for BB02 -> BB06 to [0 .. 1]
Setting edge weights for BB06 -> BB03 to [0 .. 1]
Setting edge weights for BB06 -> BB05 to [0 .. 0]
Redirecting non-loop BB01 -> BB04 to BB01 -> BB06
Setting edge weights for BB01 -> BB06 to [0 .. 1]
Reducing profile weight of BB04 from 4870144 to 4870143
Setting weight of BB04 -> BB03 to 4870142 (iterate loop)
Setting weight of BB04 -> BB05 to 0.9999998 (exit loop)
Setting edge weights for BB04 -> BB03 to [4870142 .. 4870142]
Setting edge weights for BB04 -> BB05 to [0.9999998 .. 0.9999998]
Profile weight of BB02 remains unchanged at 1
Setting weight of BB06 -> BB03 to 0.9999998 (enter loop)
Setting weight of BB06 -> BB05 to 2.053327e-07 (avoid loop)
Setting edge weights for BB06 -> BB03 to [0.9999998 .. 0.9999998]
Setting edge weights for BB06 -> BB05 to [2.053327e-07 .. 2.053327e-07]
Duplicated loop exit block at BB06 for loop (BB03 - BB04)
Estimated code size expansion is 17
------------ BB06 [???..???) -> BB05 (cond), preds={BB01,BB02} succs={BB03,BB05}
***** BB06
STMT00006 ( 0x018[E-] ... ??? )
( 11, 17) [000028] ----G------ * JTRUE void
( 9, 15) [000029] J---G--N--- \--* GE int
( 3, 2) [000030] ----------- +--* LCL_VAR int V02 loc1
( 5, 12) [000031] n---G------ \--* IND int
( 3, 10) [000032] H---------- \--* CNS_INT(h) long 0x7ffefe7b4cb0 static Fseq[InnerIterationCount]
------------ BB04 [018..020) -> BB03 (cond), preds={BB03} succs={BB05,BB03}
***** BB04
STMT00002 ( 0x018[E-] ... 0x01E )
( 11, 17) [000010] ----G------ * JTRUE void
( 9, 15) [000009] J---G--N--- \--* LT int
( 3, 2) [000006] ----------- +--* LCL_VAR int V02 loc1
( 5, 12) [000008] n---G------ \--* IND int
( 3, 10) [000007] H---------- \--* CNS_INT(h) long 0x7ffefe7b4cb0 static Fseq[InnerIterationCount]
*************** Finishing PHASE Invert loops
Trees after Invert loops
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BBnum BBid ref try hnd preds weight IBC lp [IL range] [jump] [EH region] [flags]
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BB01 [0004] 1 1 48701 [???..???)-> BB06 (always) i internal IBC
BB02 [0000] 0 0.00 1 [000..006) i IBC
BB06 [0005] 2 BB01,BB02 0.00 1 [???..???)-> BB05 ( cond ) internal IBC
BB03 [0001] 2 BB04,BB06 100.00 4870143 [006..018) i hascall bwd bwd-target IBC
BB04 [0002] 1 BB03 0.00 1 [018..020)-> BB03 ( cond ) i bwd bwd-src IBC osr-entry
BB05 [0003] 2 BB04,BB06 0 0 [020..022) (return) i rare IBC
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