JIT: Fix liveness for dependently promoted TYP_LONGs on x86

[jakobbotsch]

We were only handling uses of promoted locals when varTypeIsStruct(lcl)
was true. For TYP_LONG promoted locals on x86 it is not.

Fix #73559

[ghost]

Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch
See info in area-owners.md if you want to be subscribed.

Issue Details

---

We were only handling uses of promoted locals when varTypeIsStruct(lcl)
was true. For TYP_LONG promoted locals on x86 it is not.

Fix #73559

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

[SingleAccretion]

LGTM. I was fixing the same issues the other day for multi-reg longs and wondered whether the current state is correct. Turns out not.

There is also this code in ref counting which I think should use the same treatment:

runtime/src/coreclr/jit/compiler.hpp

Lines 1953 to 1964 in d63c65d

	if (varTypeIsStruct(lvType) && propagate)
	{
	// For promoted struct locals, increment lvRefCnt on its field locals as well.
	if (promotionType == Compiler::PROMOTION_TYPE_INDEPENDENT ||
	promotionType == Compiler::PROMOTION_TYPE_DEPENDENT)
	{
	for (unsigned i = lvFieldLclStart; i < lvFieldLclStart + lvFieldCnt; ++i)
	{
	comp->lvaTable[i].incRefCnts(weight, comp, state, false); // Don't propagate
	}
	}
	}

Many of these conditions look a bit pointless, they could just be checking promotion type and/or lvPromoted directly, but that's not a 7.0 issue, naturally.

[kunalspathak]

LGTM. I am wondering if these 2 places also need fixup?

runtime/src/coreclr/jit/codegencommon.cpp

Line 3387 in 9865cc7

if (varTypeIsStruct(varDsc) &&

runtime/src/coreclr/jit/compiler.hpp

Line 1906 in 9865cc7

if (varTypeIsStruct(lvType))

[jakobbotsch]

LGTM. I am wondering if these 2 places also need fixup?

runtime/src/coreclr/jit/codegencommon.cpp

Line 3387 in 9865cc7

if (varTypeIsStruct(varDsc) &&

runtime/src/coreclr/jit/compiler.hpp

Line 1906 in 9865cc7

if (varTypeIsStruct(lvType))

I don't think it would hurt, but it is not necessary today. We never promote TYP_LONG parameters independently (first one) and there is a != TYP_STRUCT check in the code that follows that covers the second one. I will leave it to avoid rerunning CI.

[kunalspathak]

LGTM

[jakobbotsch]

Actually, CI looked particularly fussy so I updated them too to also rerun it.