RPCS3/llvm
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm.git synced 2025-04-02 21:31:41 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Use a WeakVH for UnknownInstructions in AliasSetTracker

Browse Source 
Summary:
This change solves the same problem as D30726, except that this only
throws out the bathwater.

AST was not correctly tracking and deleting UnknownInstructions via
handles.  The existing code only tracks "pointers" in its
`ASTCallbackVH`, so an UnknownInstruction (that isn't also def'ing a
pointer used by another memory instruction) never gets a
`ASTCallbackVH`.

There are two other ways to solve this problem:

 - Use the `PointerRec` scheme for both known and unknown instructions.
 - Use a `CallbackVH` that erases the offending Instruction from the
   UnknownInstruction list.

Both of the above changes seemed to be significantly (and unnecessarily
IMO) more complex than this.

Reviewers: chandlerc, dberlin, hfinkel, reames

Subscribers: mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D30849

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297539 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Sanjoy Das 2017-03-11 01:15:48 +00:00
parent 5b9a142f57
commit c32a57361b
3 changed files with 37 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
include/llvm/Analysis/AliasSetTracker.h
View File

@ -121,7 +121,10 @@ class AliasSet : public ilist_node<AliasSet> {
AliasSet *Forward;
/// All instructions without a specific address in this alias set.
std::vector<AssertingVH<Instruction> > UnknownInsts;
/// In rare cases this vector can have a null'ed out WeakVH
/// instances (can happen if some other loop pass deletes an
/// instruction in this list).
std::vector<WeakVH> UnknownInsts;
/// Number of nodes pointing to this AliasSet plus the number of AliasSets
/// forwarding to it.
@ -171,7 +174,7 @@ class AliasSet : public ilist_node<AliasSet> {
Instruction *getUnknownInst(unsigned i) const {
assert(i < UnknownInsts.size());
return UnknownInsts[i];
return cast_or_null<Instruction>(UnknownInsts[i]);
}
public:

36
lib/Analysis/AliasSetTracker.cpp
View File

@ -199,9 +199,10 @@ bool AliasSet::aliasesPointer(const Value *Ptr, uint64_t Size,
// Check the unknown instructions...
if (!UnknownInsts.empty()) {
for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i)
if (AA.getModRefInfo(UnknownInsts[i],
MemoryLocation(Ptr, Size, AAInfo)) != MRI_NoModRef)
return true;
if (auto *Inst = getUnknownInst(i))
if (AA.getModRefInfo(Inst, MemoryLocation(Ptr, Size, AAInfo)) !=
MRI_NoModRef)
return true;
}
return false;
@ -217,10 +218,12 @@ bool AliasSet::aliasesUnknownInst(const Instruction *Inst,
return false;
for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i) {
ImmutableCallSite C1(getUnknownInst(i)), C2(Inst);
if (!C1 || !C2 || AA.getModRefInfo(C1, C2) != MRI_NoModRef ||
AA.getModRefInfo(C2, C1) != MRI_NoModRef)
return true;
if (auto *Inst = getUnknownInst(i)) {
ImmutableCallSite C1(Inst), C2(Inst);
if (!C1 || !C2 || AA.getModRefInfo(C1, C2) != MRI_NoModRef ||
AA.getModRefInfo(C2, C1) != MRI_NoModRef)
return true;
}
}
for (iterator I = begin(), E = end(); I != E; ++I)
@ -471,7 +474,8 @@ void AliasSetTracker::add(const AliasSetTracker &AST) {
// If there are any call sites in the alias set, add them to this AST.
for (unsigned i = 0, e = AS.UnknownInsts.size(); i != e; ++i)
add(AS.UnknownInsts[i]);
if (auto *Inst = AS.getUnknownInst(i))
add(Inst);
// Loop over all of the pointers in this alias set.
for (AliasSet::iterator ASI = AS.begin(), E = AS.end(); ASI != E; ++ASI) {
@ -489,19 +493,6 @@ void AliasSetTracker::add(const AliasSetTracker &AST) {
// dangling pointers to deleted instructions.
//
void AliasSetTracker::deleteValue(Value *PtrVal) {
// If this is a call instruction, remove the callsite from the appropriate
// AliasSet (if present).
if (Instruction *Inst = dyn_cast<Instruction>(PtrVal)) {
if (Inst->mayReadOrWriteMemory()) {
// Scan all the alias sets to see if this call site is contained.
for (iterator I = begin(), E = end(); I != E;) {
iterator Cur = I++;
if (!Cur->Forward)
Cur->removeUnknownInst(*this, Inst);
}
}
}
// First, look up the PointerRec for this pointer.
PointerMapType::iterator I = PointerMap.find_as(PtrVal);
if (I == PointerMap.end()) return; // Noop
@ -633,7 +624,8 @@ void AliasSet::print(raw_ostream &OS) const {
OS << "\n " << UnknownInsts.size() << " Unknown instructions: ";
for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i) {
if (i) OS << ", ";
UnknownInsts[i]->printAsOperand(OS);
if (auto *I = getUnknownInst(i))
I->printAsOperand(OS);
}
}
OS << "\n";

18
test/Transforms/LICM/pr32129.ll Normal file
View File

@ -0,0 +1,18 @@
; RUN: opt -S -licm -loop-unswitch -licm < %s | FileCheck %s
declare void @llvm.experimental.guard(i1, ...)
define void @test() {
; CHECK-LABEL: @test(
; CHECK-NOT: guard
entry:
br label %header
header:
br label %loop
loop:
%0 = icmp ult i32 0, 400
call void (i1, ...) @llvm.experimental.guard(i1 %0, i32 9) [ "deopt"() ]
br i1 undef, label %header, label %loop
}