JIT: Handle primitive remainder stores to regularly promoted fields in physical promotion #87217
Conversation
…n physical promotion
If the remainder of a block copy is handled as a primitive, then it is
possible that the destination or source is a regularly promoted field.
In this case we do not have to DNER it.
Example. Before:
```
Processing block operation [000009] that involves replacements
V08 (field V02.hasValue (fldOffset=0x0)) <- V16 (V00.[000..001)) (last use)
Remainder: [004..008)
=> Remainder strategy: int at +004
Local V00 should not be enregistered because: was accessed as a local field
Local V02 should not be enregistered because: was accessed as a local field
New statement:
STMT00003 ( 0x00D[E-] ... 0x00E )
[000090] -A--------- ▌ COMMA void
[000087] DA--------- ├──▌ STORE_LCL_VAR bool V08 tmp4
[000086] ----------- │ └──▌ LCL_VAR bool V16 tmp12 (last use)
[000089] UA--------- └──▌ STORE_LCL_FLD int (P) V02 loc1 [+4]
▌ bool V02.<unknown class>:hasValue (offs=0x00) -> V08 tmp4
▌ int V02.<unknown class>:value (offs=0x04) -> V09 tmp5
[000088] ----------- └──▌ LCL_FLD int V00 arg0 [+4]
```
After:
```
Processing block operation [000009] that involves replacements
V08 (field V02.hasValue (fldOffset=0x0)) <- V16 (V00.[000..001)) (last use)
Remainder: [004..008)
=> Remainder strategy: int at +004
Local V00 should not be enregistered because: was accessed as a local field
New statement:
STMT00003 ( 0x00D[E-] ... 0x00E )
[000090] -A--------- ▌ COMMA void
[000087] DA--------- ├──▌ STORE_LCL_VAR bool V08 tmp4
[000086] ----------- │ └──▌ LCL_VAR bool V16 tmp12 (last use)
[000089] DA--------- └──▌ STORE_LCL_VAR int V09 tmp5
[000088] ----------- └──▌ LCL_FLD int V00 arg0 [+4]
```
ghost
assigned 
dotnet-issue-labeler
bot
added
the
area-CodeGen-coreclr
|
Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch Issue DetailsIf the remainder of a block copy is handled as a primitive, then it is possible that the destination or source is a regularly promoted field. In this case we do not have to DNER it. For example Example. Before: STMT00003 ( 0x00D[E-] ... 0x00E )
[000009] DA--------- ▌ STORE_LCL_VAR struct<System.Nullable`1, 8>(P) V02 loc1
▌ bool V02.<unknown class>:hasValue (offs=0x00) -> V08 tmp4
▌ int V02.<unknown class>:value (offs=0x04) -> V09 tmp5
[000008] ----------- └──▌ LCL_VAR struct<System.Nullable`1, 8> V00 arg0 (last use)
Processing block operation [000009] that involves replacements
V08 (field V02.hasValue (fldOffset=0x0)) <- V16 (V00.[000..001)) (last use)
Remainder: [004..008)
=> Remainder strategy: int at +004
Local V00 should not be enregistered because: was accessed as a local field
Local V02 should not be enregistered because: was accessed as a local field
New statement:
STMT00003 ( 0x00D[E-] ... 0x00E )
[000090] -A--------- ▌ COMMA void
[000087] DA--------- ├──▌ STORE_LCL_VAR bool V08 tmp4
[000086] ----------- │ └──▌ LCL_VAR bool V16 tmp12 (last use)
[000089] UA--------- └──▌ STORE_LCL_FLD int (P) V02 loc1 [+4]
▌ bool V02.<unknown class>:hasValue (offs=0x00) -> V08 tmp4
▌ int V02.<unknown class>:value (offs=0x04) -> V09 tmp5
[000088] ----------- └──▌ LCL_FLD int V00 arg0 [+4]After: STMT00003 ( 0x00D[E-] ... 0x00E )
[000009] DA--------- ▌ STORE_LCL_VAR struct<System.Nullable`1, 8>(P) V02 loc1
▌ bool V02.<unknown class>:hasValue (offs=0x00) -> V08 tmp4
▌ int V02.<unknown class>:value (offs=0x04) -> V09 tmp5
[000008] ----------- └──▌ LCL_VAR struct<System.Nullable`1, 8> V00 arg0 (last use)
Processing block operation [000009] that involves replacements
V08 (field V02.hasValue (fldOffset=0x0)) <- V16 (V00.[000..001)) (last use)
Remainder: [004..008)
=> Remainder strategy: int at +004
Local V00 should not be enregistered because: was accessed as a local field
New statement:
STMT00003 ( 0x00D[E-] ... 0x00E )
[000090] -A--------- ▌ COMMA void
[000087] DA--------- ├──▌ STORE_LCL_VAR bool V08 tmp4
[000086] ----------- │ └──▌ LCL_VAR bool V16 tmp12 (last use)
[000089] DA--------- └──▌ STORE_LCL_VAR int V09 tmp5
[000088] ----------- └──▌ LCL_FLD int V00 arg0 [+4]
|
|
cc @dotnet/jit-contrib PTAL @EgorBo. Diffs with physical promotion. Quite large x86/arm32 diffs compared to 64-bit, not quite sure why, will try to take a closer look, and also look at some of the regressions. Diffs without old promotion. None as expected since there are no regular promoted fields in this case. |
|
/azp run runtime-coreclr jitstress, runtime-coreclr libraries-jitstress, runtime-jit-experimental |
|
Azure Pipelines successfully started running 3 pipeline(s). |
We only promote struct parameters if they are passed in registers or as implicit byrefs, which particularly means a parameter
There are very few, but the one I looked at was just due to different register allocation because of a new independent promotion taking up a register and another local then being spilled instead. |
If the remainder of a block copy is handled as a primitive, then it is possible that the destination or source is a regularly promoted field. In this case we do not have to DNER it.
Example. Before:
After: