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[InstCombine] Remove unused entries in gc-live bundle of statepoint

If some of gc live value are not used in gc.relocate we can remove them
from gc-live bundle of statepoint instruction.

Also the CL removes duplicated Values in gc-live bundle.

Reviewers: reames, dantrushin
Reviewed By: dantrushin
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D85959
This commit is contained in:
Serguei Katkov 2020-08-14 12:00:09 +07:00
parent ce0e164b61
commit facbe0803e
4 changed files with 112 additions and 9 deletions

View File

@ -1561,6 +1561,16 @@ public:
static CallInst *Create(CallInst *CI, ArrayRef<OperandBundleDef> Bundles,
Instruction *InsertPt = nullptr);
/// Create a clone of \p CI with a different set of operand bundles and
/// insert it before \p InsertPt.
///
/// The returned call instruction is identical \p CI in every way except that
/// the operand bundle for the new instruction is set to the operand bundle
/// in \p Bundle.
static CallInst *CreateWithReplacedBundle(CallInst *CI,
OperandBundleDef Bundle,
Instruction *InsertPt = nullptr);
/// Generate the IR for a call to malloc:
/// 1. Compute the malloc call's argument as the specified type's size,
/// possibly multiplied by the array size if the array size is not
@ -3778,6 +3788,16 @@ public:
static InvokeInst *Create(InvokeInst *II, ArrayRef<OperandBundleDef> Bundles,
Instruction *InsertPt = nullptr);
/// Create a clone of \p II with a different set of operand bundles and
/// insert it before \p InsertPt.
///
/// The returned invoke instruction is identical to \p II in every way except
/// that the operand bundle for the new instruction is set to the operand
/// bundle in \p Bundle.
static InvokeInst *CreateWithReplacedBundle(InvokeInst *II,
OperandBundleDef Bundles,
Instruction *InsertPt = nullptr);
// get*Dest - Return the destination basic blocks...
BasicBlock *getNormalDest() const {
return cast<BasicBlock>(Op<NormalDestOpEndIdx>());

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@ -515,6 +515,18 @@ CallInst *CallInst::Create(CallInst *CI, ArrayRef<OperandBundleDef> OpB,
return NewCI;
}
CallInst *CallInst::CreateWithReplacedBundle(CallInst *CI, OperandBundleDef OpB,
Instruction *InsertPt) {
SmallVector<OperandBundleDef, 2> OpDefs;
for (unsigned i = 0, e = CI->getNumOperandBundles(); i < e; ++i) {
auto ChildOB = CI->getOperandBundleAt(i);
if (ChildOB.getTagName() != OpB.getTag())
OpDefs.emplace_back(ChildOB);
}
OpDefs.emplace_back(OpB);
return CallInst::Create(CI, OpDefs, InsertPt);
}
// Update profile weight for call instruction by scaling it using the ratio
// of S/T. The meaning of "branch_weights" meta data for call instruction is
// transfered to represent call count.
@ -826,6 +838,18 @@ InvokeInst *InvokeInst::Create(InvokeInst *II, ArrayRef<OperandBundleDef> OpB,
return NewII;
}
InvokeInst *InvokeInst::CreateWithReplacedBundle(InvokeInst *II,
OperandBundleDef OpB,
Instruction *InsertPt) {
SmallVector<OperandBundleDef, 2> OpDefs;
for (unsigned i = 0, e = II->getNumOperandBundles(); i < e; ++i) {
auto ChildOB = II->getOperandBundleAt(i);
if (ChildOB.getTagName() != OpB.getTag())
OpDefs.emplace_back(ChildOB);
}
OpDefs.emplace_back(OpB);
return InvokeInst::Create(II, OpDefs, InsertPt);
}
LandingPadInst *InvokeInst::getLandingPadInst() const {
return cast<LandingPadInst>(getUnwindDest()->getFirstNonPHI());

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@ -1487,7 +1487,8 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
break;
}
case Intrinsic::experimental_gc_statepoint: {
auto &GCSP = *cast<GCStatepointInst>(II);
GCStatepointInst &GCSP = *cast<GCStatepointInst>(II);
SmallPtrSet<Value *, 32> LiveGcValues;
for (const GCRelocateInst *Reloc : GCSP.getGCRelocates()) {
GCRelocateInst &GCR = *const_cast<GCRelocateInst *>(Reloc);
@ -1539,7 +1540,48 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
// Canonicalize on the type from the uses to the defs
// TODO: relocate((gep p, C, C2, ...)) -> gep(relocate(p), C, C2, ...)
LiveGcValues.insert(BasePtr);
LiveGcValues.insert(DerivedPtr);
}
Optional<OperandBundleUse> Bundle =
GCSP.getOperandBundle(LLVMContext::OB_gc_live);
unsigned NumOfGCLives = LiveGcValues.size();
if (!Bundle.hasValue() || NumOfGCLives == Bundle->Inputs.size())
break;
// We can reduce the size of gc live bundle.
DenseMap<Value *, unsigned> Val2Idx;
std::vector<Value *> NewLiveGc;
for (unsigned I = 0, E = Bundle->Inputs.size(); I < E; ++I) {
Value *V = Bundle->Inputs[I];
if (Val2Idx.count(V))
continue;
if (LiveGcValues.count(V)) {
Val2Idx[V] = NewLiveGc.size();
NewLiveGc.push_back(V);
} else
Val2Idx[V] = NumOfGCLives;
}
// Update all gc.relocates
for (const GCRelocateInst *Reloc : GCSP.getGCRelocates()) {
GCRelocateInst &GCR = *const_cast<GCRelocateInst *>(Reloc);
Value *BasePtr = GCR.getBasePtr();
assert(Val2Idx.count(BasePtr) && Val2Idx[BasePtr] != NumOfGCLives &&
"Missed live gc for base pointer");
auto *OpIntTy1 = GCR.getOperand(1)->getType();
GCR.setOperand(1, ConstantInt::get(OpIntTy1, Val2Idx[BasePtr]));
Value *DerivedPtr = GCR.getDerivedPtr();
assert(Val2Idx.count(DerivedPtr) && Val2Idx[DerivedPtr] != NumOfGCLives &&
"Missed live gc for derived pointer");
auto *OpIntTy2 = GCR.getOperand(2)->getType();
GCR.setOperand(2, ConstantInt::get(OpIntTy2, Val2Idx[DerivedPtr]));
}
// Create new statepoint instruction.
OperandBundleDef NewBundle("gc-live", NewLiveGc);
if (isa<CallInst>(II))
return CallInst::CreateWithReplacedBundle(cast<CallInst>(II), NewBundle);
else
return InvokeInst::CreateWithReplacedBundle(cast<InvokeInst>(II),
NewBundle);
break;
}
case Intrinsic::experimental_guard: {

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@ -1,3 +1,4 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -instcombine-max-iterations=1 -S | FileCheck %s
; These tests check the optimizations specific to
; pointers being relocated at a statepoint.
@ -6,6 +7,18 @@
declare void @func()
define i1 @test_null(i1 %cond) gc "statepoint-example" {
; CHECK-LABEL: @test_null(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[COND:%.*]], label [[LEFT:%.*]], label [[RIGHT:%.*]]
; CHECK: right:
; CHECK-NEXT: br label [[MERGE:%.*]]
; CHECK: left:
; CHECK-NEXT: [[SAFEPOINT_TOKEN:%.*]] = tail call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* nonnull @func, i32 0, i32 0, i32 0, i32 0) [ "gc-live"() ]
; CHECK-NEXT: br label [[MERGE]]
; CHECK: merge:
; CHECK-NEXT: [[SAFEPOINT_TOKEN2:%.*]] = tail call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* nonnull @func, i32 0, i32 0, i32 0, i32 0) [ "gc-live"() ]
; CHECK-NEXT: ret i1 true
;
entry:
br i1 %cond, label %left, label %right
@ -23,13 +36,21 @@ merge:
%pnew2 = call i32* @llvm.experimental.gc.relocate.p1i32(token %safepoint_token2, i32 0, i32 0)
%cmp = icmp eq i32* %pnew2, null
ret i1 %cmp
; CHECK-LABEL: test_null
; CHECK-NOT: %pnew
; CHECK-NOT: %pnew2
; CHECK: ret i1 true
}
define i32* @test_undef(i1 %cond) gc "statepoint-example" {
; CHECK-LABEL: @test_undef(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[COND:%.*]], label [[LEFT:%.*]], label [[RIGHT:%.*]]
; CHECK: right:
; CHECK-NEXT: br label [[MERGE:%.*]]
; CHECK: left:
; CHECK-NEXT: [[SAFEPOINT_TOKEN:%.*]] = tail call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* nonnull @func, i32 0, i32 0, i32 0, i32 0) [ "gc-live"() ]
; CHECK-NEXT: br label [[MERGE]]
; CHECK: merge:
; CHECK-NEXT: [[SAFEPOINT_TOKEN2:%.*]] = tail call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* nonnull @func, i32 0, i32 0, i32 0, i32 0) [ "gc-live"() ]
; CHECK-NEXT: ret i32* undef
;
entry:
br i1 %cond, label %left, label %right
@ -46,10 +67,6 @@ merge:
%safepoint_token2 = tail call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @func, i32 0, i32 0, i32 0, i32 0) ["gc-live" (i32* %pnew_phi)]
%pnew2 = call i32* @llvm.experimental.gc.relocate.p1i32(token %safepoint_token2, i32 0, i32 0)
ret i32* %pnew2
; CHECK-LABEL: test_undef
; CHECK-NOT: %pnew
; CHECK-NOT: %pnew2
; CHECK: ret i32* undef
}
declare token @llvm.experimental.gc.statepoint.p0f_isVoidf(i64, i32, void ()*, i32, i32, ...)