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Missing GTF_ASG and GTF_ALL_EFFECT on GenTree nodes. #13758
Description
Sometimes we are missing GTF_ASG flag for calls when create a setup argument node in fgArgInfo::EvalArgsToTemps(). It creates an unwanted effect that call to gtUpdateSideEffects(tree, stmt) could change flags when the trees are unchanged:
before calling gtUpdateSideEffects(000055, stmt):
N019 ( 51, 40) [000068] --CXG------- * JTRUE void
N018 ( 49, 38) [000067] J-CXG--N---- \--* LT int $148
N016 ( 47, 36) [000065] --CXG------- HERE +--* CALLV stub int System.Collections.IComparer.Compare $383
N010 ( 18, 11) [000131] -ACXG---R-L- arg2 SETUP | +--* ASG ref $346
N009 ( 1, 1) [000130] D------N---- | | +--* LCL_VAR ref V12 tmp5 d:2 $346
N008 ( 18, 11) [000059] --CXG------- | | \--* CALL r2r_ind ref System.Array.GetValue $346
N006 ( 3, 2) [000049] *--XG------- this in rcx | | +--* IND ref <l:$286, c:$285>
N005 ( 1, 1) [000048] ------------ | | | \--* LCL_VAR byref V00 this u:1 Zero Fseq[keys] $80
N007 ( 1, 1) [000055] ------------ arg1 in rdx | | \--* LCL_VAR int V05 loc2 u:5 (last use) $147
N012 ( 1, 1) [000132] ------------ arg2 in rdx | +--* LCL_VAR ref V12 tmp5 u:2 (last use) $346
N013 ( 1, 1) [000064] ------------ arg3 in r8 | +--* LCL_VAR ref V04 loc1 u:2 $205
N014 ( 1, 1) [000062] ------------ this in rcx | +--* LCL_VAR ref V09 tmp2 u:2 (last use) <l:$241, c:$341>
N015 ( 3, 10) [000127] ------------ arg1 in r11 | \--* CNS_INT(h) long 0xd1ffab1e ftn REG r11 $480
N017 ( 1, 1) [000066] ------------ \--* CNS_INT int 0 $40
after:
N019 ( 51, 40) [000068] -ACXG------- * JTRUE void
N018 ( 49, 38) [000067] JACXG--N---- \--* LT int $148
N016 ( 47, 36) [000065] -ACXG------- HERE +--* CALLV stub int System.Collections.IComparer.Compare $383
N010 ( 18, 11) [000131] -ACXG---R-L- arg2 SETUP | +--* ASG ref $346
N009 ( 1, 1) [000130] D------N---- | | +--* LCL_VAR ref V12 tmp5 d:2 $346
N008 ( 18, 11) [000059] --CXG------- | | \--* CALL r2r_ind ref System.Array.GetValue $346
N006 ( 3, 2) [000049] *--XG------- this in rcx | | +--* IND ref <l:$286, c:$285>
N005 ( 1, 1) [000048] ------------ | | | \--* LCL_VAR byref V00 this u:1 Zero Fseq[keys] $80
N007 ( 1, 1) [000055] ------------ arg1 in rdx | | \--* LCL_VAR int V05 loc2 u:5 (last use) $147
N012 ( 1, 1) [000132] ------------ arg2 in rdx | +--* LCL_VAR ref V12 tmp5 u:2 (last use) $346
N013 ( 1, 1) [000064] ------------ arg3 in r8 | +--* LCL_VAR ref V04 loc1 u:2 $205
N014 ( 1, 1) [000062] ------------ this in rcx | +--* LCL_VAR ref V09 tmp2 u:2 (last use) <l:$241, c:$341>
N015 ( 3, 10) [000127] ------------ arg1 in r11 | \--* CNS_INT(h) long 0xd1ffab1e ftn REG r11 $480
N017 ( 1, 1) [000066] ------------ \--* CNS_INT int 0 $40
see that flags on [000065] have changed, but they should not.
The same happens with GTF_ALL_EFFECT on addr modes.
The fix for it is simple and published in dotnet/coreclr#27732, however, the fix create 0.1% size regression because of another issue. So I will postpone it until another issue is fixed.
Along the way fix that we don't print fgMorphTree block, stmt(after) if only the flags were changed.
category:correctness
theme:ir
skill-level:intermediate
cost:medium
Activity
[-]Missing flags on GenTree nodes.[/-][+]Missing `GTF_ASG` and `GTF_ALL_EFFECT` on GenTree nodes.[/+]AndyAyersMS commentedon May 1, 2020
Moving this to future.
JIT: Improve call args interference checking when stores are involved (…