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[RDF] Further improve handling of multiple phis reached from shadows

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llvm-svn: 280987
This commit is contained in:
Krzysztof Parzyszek 2016-09-08 20:48:42 +00:00
parent 60cc519524
commit 8753120a11
2 changed files with 56 additions and 31 deletions
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47
lib/Target/Hexagon/RDFLiveness.cpp
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@ -109,9 +109,8 @@ NodeList Liveness::getAllReachingDefs(RegisterRef RefRR,
continue;
// Stop at the covering/overwriting def of the initial register reference.
RegisterRef RR = TA.Addr->getRegRef();
if (RAI.covers(RR, RefRR))
if (!DFG.IsPreservingDef(TA))
continue;
if (!DFG.IsPreservingDef(TA) && RAI.covers(RR, RefRR))
continue;
// Get the next level of reaching defs. This will include multiple
// reaching defs for shadows.
for (auto S : DFG.getRelatedRefs(TA.Addr->getOwner(DFG), TA))
@ -336,13 +335,6 @@ void Liveness::computePhiInfo() {
std::map<NodeId,std::map<NodeId,RegisterSet>> PhiUp;
std::vector<NodeId> PhiUQ; // Work list of phis for upward propagation.
auto isEntryPhi = [this] (NodeId P) -> bool {
auto PA = DFG.addr<PhiNode*>(P);
NodeAddr<BlockNode*> BA = PA.Addr->getOwner(DFG);
MachineBasicBlock *BB = BA.Addr->getCode();
return BB == &BB->getParent()->front();
};
// Go over all phis.
for (NodeAddr<PhiNode*> PhiA : Phis) {
// Go over all defs and collect the reached uses that are non-phi uses
@ -440,38 +432,31 @@ void Liveness::computePhiInfo() {
// the set of registers defined between this phi (PhiA) and the owner phi
// of the reaching def.
NodeSet SeenUses;
for (auto I : PhiRefs) {
if (!DFG.IsRef<NodeAttrs::Use>(I) || SeenUses.count(I.Id))
continue;
NodeAddr<UseNode*> UA = I;
std::map<NodeId,RegisterSet> &PUM = PhiUp[UA.Id];
RegisterSet DefRRs;
NodeId RP = 0; // Phi node reached upwards.
// Given a phi use UA, traverse all related phi uses (including UA).
// The related phi uses may reach different phi nodes or may reach the
// same phi node. If multiple uses reach the same phi P, the intervening
// defs must be accumulated for all such uses. To group all such uses
// into one set, map their node ids to the first use id that reaches P.
std::map<NodeId,NodeId> FirstUse; // Phi reached up -> first phi use.
for (NodeAddr<UseNode*> VA : DFG.getRelatedRefs(PhiA, UA)) {
SeenUses.insert(VA.Id);
RegisterSet DefRRs;
for (NodeAddr<DefNode*> DA : getAllReachingDefs(VA)) {
if (DA.Addr->getFlags() & NodeAttrs::PhiRef) {
// For all related phi uses, if they are reached by a phi def,
// all the reaching defs must belong to the same phi node.
// The only exception to that are the function entry phis, but
// are not playing any role in the subsequent propagation.
NodeId P = DA.Addr->getOwner(DFG).Id;
if (RP == 0)
RP = P;
assert(P == RP || (isEntryPhi(P) && isEntryPhi(RP)));
} else
DefRRs.insert(DA.Addr->getRegRef());
NodeId RP = DA.Addr->getOwner(DFG).Id;
NodeId FU = FirstUse.insert({RP,VA.Id}).first->second;
PhiUp[FU][RP].insert(DefRRs.begin(), DefRRs.end());
}
DefRRs.insert(DA.Addr->getRegRef());
}
}
// Do not add reaching information for entry phis. The data collection
// above was done under the assumption that registers on all phis
// contain all actual data-flow (i.e. a phi for R0 will not convey
// data-flow information for D0). This is not true for entry phis.
// They are not participating in the propagation anyway, so that is
// not a problem.
if (RP && !isEntryPhi(RP))
PUM[RP] = DefRRs;
}
}

40
test/CodeGen/Hexagon/rdf-multiple-phis-up.ll Normal file
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@ -0,0 +1,40 @@
; RUN: llc -march=hexagon < %s | FileCheck %s
; REQUIRES: asserts
; Check that we do not crash.
; CHECK: call foo
target triple = "hexagon"
%struct.0 = type { i8*, i8*, [2 x i8*], i32, i32, i8*, i32, i32, i32, i32, i32, [2 x i32], i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }
define i32 @fred(i8* %p0) local_unnamed_addr #0 {
entry:
%0 = bitcast i8* %p0 to %struct.0*
br i1 undef, label %if.then21, label %for.body.i
if.then21: ; preds = %entry
%.pr = load i32, i32* undef, align 4
switch i32 %.pr, label %cleanup [
i32 1, label %for.body.i
i32 3, label %if.then60
]
for.body.i: ; preds = %for.body.i, %if.then21, %entry
%1 = load i8, i8* undef, align 1
%cmp7.i = icmp ugt i8 %1, -17
br i1 %cmp7.i, label %cleanup, label %for.body.i
if.then60: ; preds = %if.then21
%call61 = call i32 @foo(%struct.0* nonnull %0) #0
br label %cleanup
cleanup: ; preds = %if.then60, %for.body.i, %if.then21
ret i32 undef
}
declare i32 @foo(%struct.0*) local_unnamed_addr #0
attributes #0 = { nounwind }