[WASM][AOT] recursive foreach loop is 17x slower than for loop over List<T> using profiled AOT

[jeromelaban]

Description

full repro is coming

Considering the following cpde:

static void Bench(List<int> array)
{
	for (int i = 0; i < innerCount; i++)
	{
		Nest(0);
	}

	void Nest(int depth)
	{
		if(depth == maxDepth)
		{
			return;
		}

		for (int i = 0; i < array.Count; i++)
		{
			Nest(depth + 1);
		}
	}
}

Changing the loop type from for to foreach results in a significant performance degradation:

profiled AOT Nested loops:

• for loop 00:00:00.0008850
• foreach loop 00:00:00.0138100

Full-AOT Nested loops:

• for loop: 00:00:00.0002350
• foreach loop: 00:00:00.0110250

Configuration

bb65067

Regression?

No

Other information

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Issue Details

---

Description

full repro is coming

Considering the following cpde:

static void Bench(List<int> array)
{
	for (int i = 0; i < innerCount; i++)
	{
		Nest(0);
	}

	void Nest(int depth)
	{
		if(depth == maxDepth)
		{
			return;
		}

		for (int i = 0; i < array.Count; i++)
		{
			Nest(depth + 1);
		}
	}
}

Changing the loop type from for to foreach results in a significant performance degradation:

profiled AOT Nested loops:

• for loop 00:00:00.0008850
• foreach loop 00:00:00.0138100

Full-AOT Nested loops:

• for loop: 00:00:00.0002350
• foreach loop: 00:00:00.0110250

Configuration

bb65067

Regression?

No

Other information

Author:	jeromelaban
Assignees:	-
Labels:	arch-wasm, untriaged
Milestone:	-

[SamMonoRT]

@kg @vargaz do we think we get to this prior to Preview 7 ?

[kg]

I don't have enough context to answer that, zoltan would

[vargaz]

@jeromelaban Does this still happen ?

[jeromelaban]

@vargaz unless #54272 is fixed, I think this still applies.

[SamMonoRT]

@jeromelaban - can we close this, seems like 54272 was closed.

[jeromelaban]

@SamMonoRT Indeed we can.