JIT: Unroll newly recognized loops

[jakobbotsch]

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Issue Details

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Based on #96751

Author:	jakobbotsch
Assignees:	jakobbotsch
Labels:	area-CodeGen-coreclr
Milestone:	-

[jakobbotsch]

/azp run runtime-coreclr jitstress, runtime-coreclr libraries-jitstress

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Azure Pipelines successfully started running 2 pipeline(s).

[jakobbotsch]

cc @dotnet/jit-contrib PTAL @BruceForstall

Diffs. Not too many cases. We may get some more when we fix

runtime/src/coreclr/jit/flowgraph.cpp

Lines 4959 to 4962 in 8f79b66

	// TODO-Quirk: For backwards compatibility always try the lexically
	// bottom-most block for the loop variable.
	BasicBlock* bottom = GetLexicallyBottomMostBlock();
	JITDUMP(" Bottom = " FMT_BB "\n", bottom->bbNum);