VSadov/Satori
1
0
Fork 0
mirror of https://github.com/VSadov/Satori.git synced 2025-06-09 17:44:48 +09:00
Code Activity

JIT: Disable old promotion for structs with significant padding (#104438)

Browse source 
When old promotion kicks in for structs with significant padding it
generally results in dependent promotion as block morphing handles these
conservatively. Disable this case and allow physical promotion to handle
it instead.
This commit is contained in:
Jakob Botsch Nielsen 2024-07-05 13:41:37 +02:00 • committed by GitHub
parent bd752c34ef
commit 8a99adad39
Signed by: github
GPG key ID: B5690EEEBB952194
5 changed files with 20 additions and 56 deletions
Download patch file Download diff file Expand all files Collapse all files

8
src/coreclr/jit/compiler.h
View file

@ -605,12 +605,6 @@ public:
unsigned char lvIsStructField : 1; // Is this local var a field of a promoted struct local?
unsigned char lvContainsHoles : 1; // Is this a promoted struct whose fields do not cover the struct local?
// True for a promoted struct that has significant padding in it.
// Significant padding is any data in the struct that is not covered by a
// promoted field and that the EE told us we need to preserve on block
// copies/inits.
unsigned char lvAnySignificantPadding : 1;
unsigned char lvIsMultiRegArg : 1; // true if this is a multireg LclVar struct used in an argument context
unsigned char lvIsMultiRegRet : 1; // true if this is a multireg LclVar struct assigned from a multireg call
@ -4210,7 +4204,6 @@ public:
CORINFO_CLASS_HANDLE typeHnd;
bool canPromote;
bool containsHoles;
bool anySignificantPadding;
bool fieldsSorted;
unsigned char fieldCnt;
lvaStructFieldInfo fields[MAX_NumOfFieldsInPromotableStruct];
@ -4219,7 +4212,6 @@ public:
: typeHnd(typeHnd)
, canPromote(false)
, containsHoles(false)
, anySignificantPadding(false)
, fieldsSorted(false)
, fieldCnt(0)
{

33
src/coreclr/jit/lclvars.cpp
View file

@ -2371,9 +2371,15 @@ bool Compiler::StructPromotionHelper::CanPromoteStructType(CORINFO_CLASS_HANDLE
if (fieldsSize != treeNodes[0].size)
{
structPromotionInfo.containsHoles = true;
}
structPromotionInfo.anySignificantPadding = treeNodes[0].hasSignificantPadding && structPromotionInfo.containsHoles;
if (treeNodes[0].hasSignificantPadding)
{
// Struct has significant data not covered by fields we would promote;
// this would typically result in dependent promotion, so leave this
// struct to physical promotion.
return false;
}
}
// Cool, this struct is promotable.
@ -2716,11 +2722,6 @@ bool Compiler::StructPromotionHelper::ShouldPromoteStructVar(unsigned lclNum)
structPromotionInfo.fieldCnt, varDsc->lvFieldAccessed);
shouldPromote = false;
}
else if (varDsc->lvIsMultiRegRet && structPromotionInfo.anySignificantPadding)
{
JITDUMP("Not promoting multi-reg returned struct local V%02u with significant padding.\n", lclNum);
shouldPromote = false;
}
#if defined(TARGET_LOONGARCH64) || defined(TARGET_RISCV64)
else if ((structPromotionInfo.fieldCnt == 2) && (varTypeIsFloating(structPromotionInfo.fields[0].fldType) ||
varTypeIsFloating(structPromotionInfo.fields[1].fldType)))
@ -2739,13 +2740,8 @@ bool Compiler::StructPromotionHelper::ShouldPromoteStructVar(unsigned lclNum)
// multiple registers?
if (compiler->lvaIsMultiregStruct(varDsc, compiler->info.compIsVarArgs))
{
if (structPromotionInfo.anySignificantPadding)
{
JITDUMP("Not promoting multi-reg struct local V%02u with significant padding.\n", lclNum);
shouldPromote = false;
}
else if ((structPromotionInfo.fieldCnt != 2) &&
!((structPromotionInfo.fieldCnt == 1) && varTypeIsSIMD(structPromotionInfo.fields[0].fldType)))
if ((structPromotionInfo.fieldCnt != 2) &&
!((structPromotionInfo.fieldCnt == 1) && varTypeIsSIMD(structPromotionInfo.fields[0].fldType)))
{
JITDUMP("Not promoting multireg struct local V%02u, because lvIsParam is true, #fields != 2 and it's "
"not a single SIMD.\n",
@ -2834,11 +2830,10 @@ void Compiler::StructPromotionHelper::PromoteStructVar(unsigned lclNum)
assert(varDsc->GetLayout()->GetClassHandle() == structPromotionInfo.typeHnd);
assert(structPromotionInfo.canPromote);
varDsc->lvFieldCnt = structPromotionInfo.fieldCnt;
varDsc->lvFieldLclStart = compiler->lvaCount;
varDsc->lvPromoted = true;
varDsc->lvContainsHoles = structPromotionInfo.containsHoles;
varDsc->lvAnySignificantPadding = structPromotionInfo.anySignificantPadding;
varDsc->lvFieldCnt = structPromotionInfo.fieldCnt;
varDsc->lvFieldLclStart = compiler->lvaCount;
varDsc->lvPromoted = true;
varDsc->lvContainsHoles = structPromotionInfo.containsHoles;
#ifdef DEBUG
// Don't stress this in LCL_FLD stress.

2
src/coreclr/jit/liveness.cpp
View file

@ -1024,7 +1024,7 @@ bool Compiler::fgComputeLifeUntrackedLocal(VARSET_TP& life,
{
// Do not consider this store dead if the parent local variable is an address exposed local or
// if the struct has any significant padding we must retain the value of.
return !varDsc.IsAddressExposed() && !varDsc.lvAnySignificantPadding;
return !varDsc.IsAddressExposed();
}
return false;

11
src/coreclr/jit/morph.cpp
View file

@ -14728,12 +14728,11 @@ PhaseStatus Compiler::fgRetypeImplicitByRefArgs()
}
// Copy the struct promotion annotations to the new temp.
LclVarDsc* newVarDsc = lvaGetDesc(newLclNum);
newVarDsc->lvPromoted = true;
newVarDsc->lvFieldLclStart = varDsc->lvFieldLclStart;
newVarDsc->lvFieldCnt = varDsc->lvFieldCnt;
newVarDsc->lvContainsHoles = varDsc->lvContainsHoles;
newVarDsc->lvAnySignificantPadding = varDsc->lvAnySignificantPadding;
LclVarDsc* newVarDsc = lvaGetDesc(newLclNum);
newVarDsc->lvPromoted = true;
newVarDsc->lvFieldLclStart = varDsc->lvFieldLclStart;
newVarDsc->lvFieldCnt = varDsc->lvFieldCnt;
newVarDsc->lvContainsHoles = varDsc->lvContainsHoles;
#ifdef DEBUG
newVarDsc->lvKeepType = true;
#endif // DEBUG

22
src/coreclr/jit/morphblock.cpp
View file

@ -359,12 +359,6 @@ void MorphInitBlockHelper::TryInitFieldByField()
return;
}
if (destLclVar->lvAnySignificantPadding)
{
JITDUMP(" dest has significant padding.\n");
return;
}
if (m_dstLclOffset != 0)
{
JITDUMP(" dest not at a zero offset.\n");
@ -775,22 +769,6 @@ void MorphCopyBlockHelper::MorphStructCases()
requiresCopyBlock = true;
}
// Can we use field by field copy for the dest?
if (m_dstDoFldStore && m_dstVarDsc->lvAnySignificantPadding)
{
JITDUMP(" dest has significant padding");
// C++ style CopyBlock with holes
requiresCopyBlock = true;
}
// Can we use field by field copy for the src?
if (m_srcDoFldStore && m_srcVarDsc->lvAnySignificantPadding)
{
JITDUMP(" src has significant padding");
// C++ style CopyBlock with holes
requiresCopyBlock = true;
}
#if defined(TARGET_ARM)
if (m_store->OperIsIndir() && m_store->AsIndir()->IsUnaligned())
{