crossgen2 getClassAlignmentRequirement returns wrong value on arm

[t-mustafin]

I hit on different input argument r1 usage generated by crossgen2 and Tier-1 compilation on lambda-expression MyStruct { int a; int b; long c; }:

var soldOutProducts = products.Where(p => p.MyStruct.a > 0x300 || p.MyStruct.b > 0x50000 || p.MyStruct.c > 0x6000000);

Code generated by crossgen2 uses r1+36:

000006 6A48 ldr r0, [r1+36]
000008 F5B0 7F40 cmp r0, 768
00000C DC14 bgt SHORT G_M16079_IG06
 ;; bbWeight=1 PerfScore 3.00
G_M16079_IG03:
00000E 6A88 ldr r0, [r1+40]
000010 F5B0 2FA0 cmp r0, 0x50000
000014 DC10 bgt SHORT G_M16079_IG06
000016 F101 002C add r0, r1, 44
00001A 6803 ldr r3, [r0]
00001C 6840 ldr r0, [r0+4]

Code generated by Tier-1 uses r1+40:

G_M16079_IG02:
000006 6A88 ldr r0, [r1+40]
000008 F5B0 7F40 cmp r0, 768
00000C DC14 bgt SHORT G_M16079_IG06
 ;; bbWeight=1 PerfScore 3.00
G_M16079_IG03:
00000E 6AC8 ldr r0, [r1+44]
000010 F5B0 2FA0 cmp r0, 0x50000
000014 DC10 bgt SHORT G_M16079_IG06
000016 F101 0030 add r0, r1, 48
00001A 6803 ldr r3, [r0]
00001C 6840 ldr r0, [r0+4]

MyStruct.cg2.dump.txt
MyStruct.cg2.S.txt
MyStruct.cg2-tier.dump.txt
MyStruct.cg2-tier.S.txt
Discussion started in PR38390

[t-mustafin]

cc @alpencolt @jkotas @mangod9

[mangod9]

@davidwrighton who has recently added a stress mode for field alignment, might be worthwhile to see if that flags this issue. Also adding @AntonLapounov if this only repros on arm.

[t-mustafin]

Seems like problem is inside for cycle. Print on line 639 shows Offset is not divisible by Alignment:

fieldSizeAndAlignment: Size = 16, Alignment = 8
offsets[4]: Field = [Linq]Product.<UnitPrice>k__BackingField, Offset = 20
fieldSizeAndAlignment: Size = 16, Alignment = 8
offsets[5]: Field = [Linq]Product.MyStruct, Offset = 36