Improve fgGetStaticFieldSeqAndAddress

[EgorBo]

It turns out it's a bit too conservative by looking only at CNS_INT nodes and in a case I found I need to rely on VN instead, e.g.:

[000106] U--XG------                         \--*  IND       long   <l:$280, c:$281>
[000027] -------N---                            \--*  ADD       long   $141
[000026] ---------U-                               +--*  CAST      long <- ulong <- uint $100
[000025] -----------                               |  \--*  LSH       int    $46
[000098] -----------                               |     +--*  XOR       int    $44
[000097] -----------                               |     |  +--*  HWINTRINSIC int     LeadingZeroCount $42
[000096] -----------                               |     |  |  \--*  CNS_INT   int    445 $41
[000095] -----------                               |     |  \--*  CNS_INT   int    31 $43
[000024] -----------                               |     \--*  CNS_INT   int    3 $45
[000132] H----------                               \--*  CNS_INT(h) long   0x1b1b6542c18 static Fseq[..] $140

In this case CAST node has $100,$100 VN that represents an integer constant (with help of #78929)

@dotnet/jit-contrib PTAL simple change.

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Issue Details

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It turns out it's a bit too conservative by looking only at CNS_INT nodes and in a case I found I need to rely on VN instead, e.g.:

[000106] U--XG------                         \--*  IND       long   <l:$280, c:$281>
[000027] -------N---                            \--*  ADD       long   $141
[000026] ---------U-                               +--*  CAST      long <- ulong <- uint $100
[000025] -----------                               |  \--*  LSH       int    $46
[000098] -----------                               |     +--*  XOR       int    $44
[000097] -----------                               |     |  +--*  HWINTRINSIC int     LeadingZeroCount $42
[000096] -----------                               |     |  |  \--*  CNS_INT   int    445 $41
[000095] -----------                               |     |  \--*  CNS_INT   int    31 $43
[000024] -----------                               |     \--*  CNS_INT   int    3 $45
[000132] H----------                               \--*  CNS_INT(h) long   0x1b1b6542c18 static Fseq[..] $140

In this case CAST node has $100,$100 VN that represents an integer constant (with help of #78929)

@dotnet/jit-contrib PTAL simple change.

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

[TIHan]

This looks like a simple and good change to me, pending CI.

Quick question, what is GTF_ICON_STATIC_HDL and why are we not including them?

[EgorBo]

GTF_ICON_STATIC_HDL

This functions looks for trees where GTF_ICON_STATIC_HDL (address of a static field basically, in this case -- address of an RVA element) is blended with constant offsets, e.g.
ADD(ICON_STATIC, 10) or ADD(ADD(ICON_STATIC, 10), LCL) where LCL has "I am a constant" VN

[EgorBo]

Failure is #78986 (fixed)