Do not fold relocatable constants into displacements

[SingleAccretion]

When creating address modes, we try to look through cascading ADDs with constants that could contribute to the final displacement (LEAs "offset"). In doing so, we were failing to take into account the possibility that said constants could be relocatable handles, such as [000016] in the following tree:

N009 ( 9, 11) [000009] ---XG------*RETURN int
N008 ( 8, 10) [000008] ---XG------\--*IND ushort
N007 ( 5, 8) [000007] -------N---\--*ADD byref
N003 ( 3, 6) [000015] -----------+--*ADD byref
N001 ( 1, 1) [000014] -----------|+--*CNS_INT long 12 field offset Fseq[_firstChar]
N002 ( 1, 4) [000016] H----------|\--*CNS_INT(h) ref 0x420068 [ICON_STR_HDL]
N006 ( 2, 2) [000006] -------N---\--*LSH long
N004 ( 1, 1) [000003] -----------+--*LCL_VAR long V00 arg0 u:1 (last use)
N005 ( 1, 1) [000005] -----------\--*CNS_INT long 1

We cannot fold such "constants" into LEAs, this change makes the address mode forming logic respect that.

Should fix the crashes seen in #68739.

No diffs are expected.

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Issue Details

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When creating address modes, we try to look through cascading ADDs with constants that could contribute to the final displacement (LEAs "offset"). In doing so, we were failing to take into account the possibility that said constants could be relocatable handles, such as [000016] in the following tree:

N009 ( 9, 11) [000009] ---XG------*RETURN int
N008 ( 8, 10) [000008] ---XG------\--*IND ushort
N007 ( 5, 8) [000007] -------N---\--*ADD byref
N003 ( 3, 6) [000015] -----------+--*ADD byref
N001 ( 1, 1) [000014] -----------|+--*CNS_INT long 12 field offset Fseq[_firstChar]
N002 ( 1, 4) [000016] H----------|\--*CNS_INT(h) ref 0x420068 [ICON_STR_HDL]
N006 ( 2, 2) [000006] -------N---\--*LSH long
N004 ( 1, 1) [000003] -----------+--*LCL_VAR long V00 arg0 u:1 (last use)
N005 ( 1, 1) [000005] -----------\--*CNS_INT long 1

We cannot fold such "constants" into LEAs, this change makes the address forming logic respect that.

Should fix the crashes seen in #68739.

No diffs are expected.

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

[SingleAccretion]

Diffs.

No code diffs as expected; unfortunately however, there is a throughput impact which I was not able to mitigate. I suppose since we're enabling #68739 (which improves TP significantly) with this correctness fix, that may yet be acceptable.

@dotnet/jit-contrib

[jakobbotsch]

LGTM, the TP impact looks insignificant to me.

[SingleAccretion]

The Mono AOT failure looks like #57361, presumably exposed by the recently merged #68288:

2022-05-05T18:04:04.8696931Z aot-compile: compiling /__w/1/s/artifacts/tests/coreclr/Linux.x64.Release/Tests/Core_Root/System.Net.Quic.dll; MONO_PATH: /__w/1/s/artifacts/tests/coreclr/Linux.x64.Release/Tests/Core_Root:/__w/1/s/artifacts/tests/coreclr/Linux.x64.Release/Tests/Core_Root
2022-05-05T18:04:04.9730403Z Mono Ahead of Time compiler - compiling assembly /__w/1/s/artifacts/tests/coreclr/Linux.x64.Release/Tests/Core_Root/System.Net.Quic.dll
2022-05-05T18:04:04.9734523Z AOTID E335E44F-900C-EC59-B454-0C7D355FE91C
2022-05-05T18:04:04.9736397Z * Assertion at /__w/1/s/src/mono/mono/metadata/custom-attrs.c:602, condition `out_obj' not met