NewGVN: Fix PR 33185 by checking whether we need to recursively
generate a phi of ops, which we don't currently support. llvm-svn: 304272
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@ -613,7 +613,7 @@ private:
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return CClass;
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}
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void initializeCongruenceClasses(Function &F);
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const Expression *makePossiblePhiOfOps(Instruction *, bool,
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const Expression *makePossiblePhiOfOps(Instruction *,
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SmallPtrSetImpl<Value *> &);
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void addPhiOfOps(PHINode *Op, BasicBlock *BB, Instruction *ExistingValue);
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@ -1937,6 +1937,7 @@ void NewGVN::touchAndErase(Map &M, const KeyType &Key) {
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}
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void NewGVN::addAdditionalUsers(Value *To, Value *User) const {
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if (isa<Instruction>(To))
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AdditionalUsers[To].insert(User);
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}
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@ -2423,7 +2424,7 @@ static bool okayForPHIOfOps(const Instruction *I) {
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// When we see an instruction that is an op of phis, generate the equivalent phi
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// of ops form.
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const Expression *
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NewGVN::makePossiblePhiOfOps(Instruction *I, bool HasBackedge,
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NewGVN::makePossiblePhiOfOps(Instruction *I,
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SmallPtrSetImpl<Value *> &Visited) {
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if (!okayForPHIOfOps(I))
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return nullptr;
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@ -2438,24 +2439,6 @@ NewGVN::makePossiblePhiOfOps(Instruction *I, bool HasBackedge,
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return nullptr;
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unsigned IDFSNum = InstrToDFSNum(I);
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// Pretty much all of the instructions we can convert to phi of ops over a
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// backedge that are adds, are really induction variables, and those are
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// pretty much pointless to convert. This is very coarse-grained for a
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// test, so if we do find some value, we can change it later.
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// But otherwise, what can happen is we convert the induction variable from
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//
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// i = phi (0, tmp)
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// tmp = i + 1
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//
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// to
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// i = phi (0, tmpphi)
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// tmpphi = phi(1, tmpphi+1)
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//
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// Which we don't want to happen. We could just avoid this for all non-cycle
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// free phis, and we made go that route.
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if (HasBackedge && I->getOpcode() == Instruction::Add)
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return nullptr;
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SmallPtrSet<const Value *, 8> ProcessedPHIs;
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// TODO: We don't do phi translation on memory accesses because it's
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// complicated. For a load, we'd need to be able to simulate a new memoryuse,
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@ -2470,6 +2453,16 @@ NewGVN::makePossiblePhiOfOps(Instruction *I, bool HasBackedge,
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// Convert op of phis to phi of ops
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for (auto &Op : I->operands()) {
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// TODO: We can't handle expressions that must be recursively translated
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// IE
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// a = phi (b, c)
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// f = use a
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// g = f + phi of something
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// To properly make a phi of ops for g, we'd have to properly translate and
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// use the instruction for f. We should add this by splitting out the
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// instruction creation we do below.
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if (isa<Instruction>(Op) && PHINodeUses.count(cast<Instruction>(Op)))
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return nullptr;
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if (!isa<PHINode>(Op))
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continue;
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auto *OpPHI = cast<PHINode>(Op);
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@ -2782,8 +2775,7 @@ void NewGVN::valueNumberInstruction(Instruction *I) {
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// Make a phi of ops if necessary
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if (Symbolized && !isa<ConstantExpression>(Symbolized) &&
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!isa<VariableExpression>(Symbolized) && PHINodeUses.count(I)) {
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// FIXME: Backedge argument
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auto *PHIE = makePossiblePhiOfOps(I, false, Visited);
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auto *PHIE = makePossiblePhiOfOps(I, Visited);
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if (PHIE)
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Symbolized = PHIE;
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}
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@ -0,0 +1,59 @@
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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt -newgvn -S %s | FileCheck %s
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@a = local_unnamed_addr global i32 9, align 4
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@.str4 = private unnamed_addr constant [6 x i8] c"D:%d\0A\00", align 1
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define i32 @main() local_unnamed_addr {
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; CHECK-LABEL: @main(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[TMP:%.*]] = load i32, i32* @a, align 4
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; CHECK-NEXT: [[CMP1_I:%.*]] = icmp ne i32 [[TMP]], 0
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; CHECK-NEXT: br label [[FOR_BODY_I:%.*]]
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; CHECK: for.body.i:
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; CHECK-NEXT: [[TMP1:%.*]] = phi i1 [ true, [[ENTRY:%.*]] ], [ false, [[COND_END_I:%.*]] ]
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; CHECK-NEXT: [[F_08_I:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[INC_I:%.*]], [[COND_END_I]] ]
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; CHECK-NEXT: [[MUL_I:%.*]] = select i1 [[CMP1_I]], i32 [[F_08_I]], i32 0
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; CHECK-NEXT: br i1 [[TMP1]], label [[COND_END_I]], label [[COND_TRUE_I:%.*]]
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; CHECK: cond.true.i:
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; CHECK-NEXT: [[DIV_I:%.*]] = udiv i32 [[MUL_I]], [[F_08_I]]
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; CHECK-NEXT: br label [[COND_END_I]]
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; CHECK: cond.end.i:
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; CHECK-NEXT: [[COND_I:%.*]] = phi i32 [ [[DIV_I]], [[COND_TRUE_I]] ], [ 0, [[FOR_BODY_I]] ]
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; CHECK-NEXT: [[INC_I]] = add nuw nsw i32 [[F_08_I]], 1
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; CHECK-NEXT: [[EXITCOND_I:%.*]] = icmp eq i32 [[INC_I]], 4
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; CHECK-NEXT: br i1 [[EXITCOND_I]], label [[FN1_EXIT:%.*]], label [[FOR_BODY_I]]
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; CHECK: fn1.exit:
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; CHECK-NEXT: [[CALL4:%.*]] = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str4, i64 0, i64 0), i32 [[COND_I]])
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; CHECK-NEXT: ret i32 0
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;
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entry:
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%tmp = load i32, i32* @a, align 4
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%cmp1.i = icmp ne i32 %tmp, 0
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br label %for.body.i
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for.body.i:
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%tmp1 = phi i1 [ true, %entry ], [ false, %cond.end.i ]
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%f.08.i = phi i32 [ 0, %entry ], [ %inc.i, %cond.end.i ]
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%mul.i = select i1 %cmp1.i, i32 %f.08.i, i32 0
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br i1 %tmp1, label %cond.end.i, label %cond.true.i
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cond.true.i:
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;; Ensure we don't replace this divide with a phi of ops that merges the wrong loop iteration value
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%div.i = udiv i32 %mul.i, %f.08.i
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br label %cond.end.i
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cond.end.i:
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%cond.i = phi i32 [ %div.i, %cond.true.i ], [ 0, %for.body.i ]
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%inc.i = add nuw nsw i32 %f.08.i, 1
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%exitcond.i = icmp eq i32 %inc.i, 4
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br i1 %exitcond.i, label %fn1.exit, label %for.body.i
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fn1.exit:
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%cond.i.lcssa = phi i32 [ %cond.i, %cond.end.i ]
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%call4= tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str4, i64 0, i64 0), i32 %cond.i.lcssa)
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ret i32 0
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}
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declare i32 @printf(i8* nocapture readonly, ...)
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