Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Improve profiled casts #90594

Merged
merged 1 commit into from
Aug 15, 2023
Merged

Improve profiled casts #90594

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
21 changes: 16 additions & 5 deletions src/coreclr/jit/importer.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5394,6 +5394,7 @@ GenTree* Compiler::impCastClassOrIsInstToTree(
// Pessimistically assume the jit cannot expand this as an inline test
bool canExpandInline = false;
bool partialExpand = false;
bool reversedMTCheck = false;
const CorInfoHelpFunc helper = info.compCompHnd->getCastingHelper(pResolvedToken, isCastClass);

CORINFO_CLASS_HANDLE exactCls = NO_CLASS_HANDLE;
Expand Down Expand Up @@ -5478,8 +5479,17 @@ GenTree* Compiler::impCastClassOrIsInstToTree(
if ((likelyCls != NO_CLASS_HANDLE) &&
(likelyClass.likelihood > (UINT32)JitConfig.JitGuardedDevirtualizationChainLikelihood()))
{
if ((info.compCompHnd->compareTypesForCast(likelyCls, pResolvedToken->hClass) ==
TypeCompareState::Must))
TypeCompareState castResult =
info.compCompHnd->compareTypesForCast(likelyCls, pResolvedToken->hClass);

// If case of MustNot we still can optimize isinst (only), e.g.:
//
// bool objIsDisposable = obj is IDisposable;
//
// when the profile tells us that obj is mostly Int32, hence, never implements that interface.
// for castclass it makes little sense as it will always throw a cast exception anyway.
if ((castResult == TypeCompareState::Must) ||
(castResult == TypeCompareState::MustNot && !isCastClass))
{
bool isAbstract = (info.compCompHnd->getClassAttribs(likelyCls) &
(CORINFO_FLG_INTERFACE | CORINFO_FLG_ABSTRACT)) != 0;
Expand All @@ -5489,6 +5499,7 @@ GenTree* Compiler::impCastClassOrIsInstToTree(
JITDUMP("Adding \"is %s (%X)\" check as a fast path for %s using PGO data.\n",
eeGetClassName(likelyCls), likelyCls, isCastClass ? "castclass" : "isinst");

reversedMTCheck = castResult == TypeCompareState::MustNot;
canExpandInline = true;
partialExpand = true;
exactCls = likelyCls;
Expand Down Expand Up @@ -5567,12 +5578,12 @@ GenTree* Compiler::impCastClassOrIsInstToTree(
// op1Copy CNS_INT
// null
//
condNull = gtNewOperNode(GT_EQ, TYP_INT, gtClone(op1), gtNewIconNode(0, TYP_REF));
condNull = gtNewOperNode(GT_EQ, TYP_INT, gtClone(op1), gtNewNull());

//
// expand the true and false trees for the condMT
//
GenTree* condFalse = gtClone(op1);
GenTree* condFalse = reversedMTCheck ? gtNewNull() : gtClone(op1);
GenTree* condTrue;
if (isCastClass)
{
Expand Down Expand Up @@ -5629,7 +5640,7 @@ GenTree* Compiler::impCastClassOrIsInstToTree(
// / \.
// qmarkMT op1Copy
//
temp = new (this, GT_COLON) GenTreeColon(TYP_REF, gtClone(op1), qmarkMT);
temp = new (this, GT_COLON) GenTreeColon(TYP_REF, reversedMTCheck ? gtNewNull() : gtClone(op1), qmarkMT);
qmarkNull = gtNewQmarkNode(TYP_REF, condNull, temp->AsColon());
qmarkNull->gtFlags |= GTF_QMARK_CAST_INSTOF;

Expand Down