[llvm] d4c667c - Avoid unnecessary uses of `MDNode::getTemporary`, NFC
Duncan P. N. Exon Smith via llvm-commits
llvm-commits at lists.llvm.org
Mon Oct 26 14:03:36 PDT 2020
Author: Duncan P. N. Exon Smith
Date: 2020-10-26T17:03:25-04:00
New Revision: d4c667c9af0335ac20015decce204c43f03a6cee
URL: https://github.com/llvm/llvm-project/commit/d4c667c9af0335ac20015decce204c43f03a6cee
DIFF: https://github.com/llvm/llvm-project/commit/d4c667c9af0335ac20015decce204c43f03a6cee.diff
LOG: Avoid unnecessary uses of `MDNode::getTemporary`, NFC
This is a long-delayed follow-up to
5e5b85098dbeaea2cfa5d01695b5d2982634d7dd.
`TempMDNode` includes a bunch of machinery for RAUW, and should only be
used when necessary. RAUW wasn't being used in any of these cases... it
was just a placeholder for a self-reference.
Where the real node was using `MDNode::getDistinct`, just replace the
temporary argument with `nullptr`.
Where the real node was using `MDNode::get`, the `replaceOperandWith`
call was "promoting" the node to a distinct one implicitly due to
self-reference detection in `MDNode::handleChangedOperand`. The
`TempMDNode` was serving a purpose by delaying uniquing, but it's way
simpler to just call `MDNode::getDistinct` in the first place.
Note that using a self-reference at all in these places is a hold-over
from before `distinct` metadata existed. It was an old trick to create
distinct nodes. It would be intrusive to change, including bitcode
upgrades, etc., and it's harmless so I'm not sure there's much value in
removing it from existing schemas. After this commit it still has a tiny
memory cost (in the extra metadata operand) but no more overhead in
construction.
Differential Revision: https://reviews.llvm.org/D90079
Added:
Modified:
clang/lib/CodeGen/CGLoopInfo.cpp
llvm/lib/Analysis/LoopInfo.cpp
llvm/lib/IR/MDBuilder.cpp
polly/lib/CodeGen/IRBuilder.cpp
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CGLoopInfo.cpp b/clang/lib/CodeGen/CGLoopInfo.cpp
index 78da72eda0cf..a02d832b84b4 100644
--- a/clang/lib/CodeGen/CGLoopInfo.cpp
+++ b/clang/lib/CodeGen/CGLoopInfo.cpp
@@ -24,8 +24,7 @@ MDNode *
LoopInfo::createLoopPropertiesMetadata(ArrayRef<Metadata *> LoopProperties) {
LLVMContext &Ctx = Header->getContext();
SmallVector<Metadata *, 4> NewLoopProperties;
- TempMDTuple TempNode = MDNode::getTemporary(Ctx, None);
- NewLoopProperties.push_back(TempNode.get());
+ NewLoopProperties.push_back(nullptr);
NewLoopProperties.append(LoopProperties.begin(), LoopProperties.end());
MDNode *LoopID = MDNode::getDistinct(Ctx, NewLoopProperties);
@@ -58,8 +57,7 @@ MDNode *LoopInfo::createPipeliningMetadata(const LoopAttributes &Attrs,
}
SmallVector<Metadata *, 4> Args;
- TempMDTuple TempNode = MDNode::getTemporary(Ctx, None);
- Args.push_back(TempNode.get());
+ Args.push_back(nullptr);
Args.append(LoopProperties.begin(), LoopProperties.end());
if (Attrs.PipelineInitiationInterval > 0) {
@@ -113,8 +111,7 @@ LoopInfo::createPartialUnrollMetadata(const LoopAttributes &Attrs,
FollowupHasTransforms);
SmallVector<Metadata *, 4> Args;
- TempMDTuple TempNode = MDNode::getTemporary(Ctx, None);
- Args.push_back(TempNode.get());
+ Args.push_back(nullptr);
Args.append(LoopProperties.begin(), LoopProperties.end());
// Setting unroll.count
@@ -176,8 +173,7 @@ LoopInfo::createUnrollAndJamMetadata(const LoopAttributes &Attrs,
FollowupHasTransforms);
SmallVector<Metadata *, 4> Args;
- TempMDTuple TempNode = MDNode::getTemporary(Ctx, None);
- Args.push_back(TempNode.get());
+ Args.push_back(nullptr);
Args.append(LoopProperties.begin(), LoopProperties.end());
// Setting unroll_and_jam.count
@@ -250,8 +246,7 @@ LoopInfo::createLoopVectorizeMetadata(const LoopAttributes &Attrs,
FollowupHasTransforms);
SmallVector<Metadata *, 4> Args;
- TempMDTuple TempNode = MDNode::getTemporary(Ctx, None);
- Args.push_back(TempNode.get());
+ Args.push_back(nullptr);
Args.append(LoopProperties.begin(), LoopProperties.end());
// Setting vectorize.predicate
@@ -307,7 +302,7 @@ LoopInfo::createLoopVectorizeMetadata(const LoopAttributes &Attrs,
Ctx,
{MDString::get(Ctx, "llvm.loop.vectorize.followup_all"), Followup}));
- MDNode *LoopID = MDNode::get(Ctx, Args);
+ MDNode *LoopID = MDNode::getDistinct(Ctx, Args);
LoopID->replaceOperandWith(0, LoopID);
HasUserTransforms = true;
return LoopID;
@@ -344,8 +339,7 @@ LoopInfo::createLoopDistributeMetadata(const LoopAttributes &Attrs,
createLoopVectorizeMetadata(Attrs, LoopProperties, FollowupHasTransforms);
SmallVector<Metadata *, 4> Args;
- TempMDTuple TempNode = MDNode::getTemporary(Ctx, None);
- Args.push_back(TempNode.get());
+ Args.push_back(nullptr);
Args.append(LoopProperties.begin(), LoopProperties.end());
Metadata *Vals[] = {MDString::get(Ctx, "llvm.loop.distribute.enable"),
@@ -359,7 +353,7 @@ LoopInfo::createLoopDistributeMetadata(const LoopAttributes &Attrs,
Ctx,
{MDString::get(Ctx, "llvm.loop.distribute.followup_all"), Followup}));
- MDNode *LoopID = MDNode::get(Ctx, Args);
+ MDNode *LoopID = MDNode::getDistinct(Ctx, Args);
LoopID->replaceOperandWith(0, LoopID);
HasUserTransforms = true;
return LoopID;
@@ -389,8 +383,7 @@ MDNode *LoopInfo::createFullUnrollMetadata(const LoopAttributes &Attrs,
}
SmallVector<Metadata *, 4> Args;
- TempMDTuple TempNode = MDNode::getTemporary(Ctx, None);
- Args.push_back(TempNode.get());
+ Args.push_back(nullptr);
Args.append(LoopProperties.begin(), LoopProperties.end());
Args.push_back(MDNode::get(Ctx, MDString::get(Ctx, "llvm.loop.unroll.full")));
diff --git a/llvm/lib/Analysis/LoopInfo.cpp b/llvm/lib/Analysis/LoopInfo.cpp
index 46d6eb6259b6..5ac92953a960 100644
--- a/llvm/lib/Analysis/LoopInfo.cpp
+++ b/llvm/lib/Analysis/LoopInfo.cpp
@@ -1017,8 +1017,7 @@ MDNode *llvm::makePostTransformationMetadata(LLVMContext &Context,
SmallVector<Metadata *, 4> MDs;
// Reserve first location for self reference to the LoopID metadata node.
- TempMDTuple TempNode = MDNode::getTemporary(Context, None);
- MDs.push_back(TempNode.get());
+ MDs.push_back(nullptr);
// Remove metadata for the transformation that has been applied or that became
// outdated.
diff --git a/llvm/lib/IR/MDBuilder.cpp b/llvm/lib/IR/MDBuilder.cpp
index 40d70f43132d..1f3bed3776d1 100644
--- a/llvm/lib/IR/MDBuilder.cpp
+++ b/llvm/lib/IR/MDBuilder.cpp
@@ -151,24 +151,20 @@ MDNode *MDBuilder::mergeCallbackEncodings(MDNode *ExistingCallbacks,
}
MDNode *MDBuilder::createAnonymousAARoot(StringRef Name, MDNode *Extra) {
- // To ensure uniqueness the root node is self-referential.
- auto Dummy = MDNode::getTemporary(Context, None);
-
- SmallVector<Metadata *, 3> Args(1, Dummy.get());
+ SmallVector<Metadata *, 3> Args(1, nullptr);
if (Extra)
Args.push_back(Extra);
if (!Name.empty())
Args.push_back(createString(Name));
- MDNode *Root = MDNode::get(Context, Args);
+ MDNode *Root = MDNode::getDistinct(Context, Args);
// At this point we have
- // !0 = metadata !{} <- dummy
- // !1 = metadata !{metadata !0} <- root
- // Replace the dummy operand with the root node itself and delete the dummy.
+ // !0 = distinct !{null} <- root
+ // Replace the reserved operand with the root node itself.
Root->replaceOperandWith(0, Root);
// We now have
- // !1 = metadata !{metadata !1} <- self-referential root
+ // !0 = distinct !{!0} <- root
return Root;
}
diff --git a/polly/lib/CodeGen/IRBuilder.cpp b/polly/lib/CodeGen/IRBuilder.cpp
index 435be74cb7e3..c2bb5e4ecdb4 100644
--- a/polly/lib/CodeGen/IRBuilder.cpp
+++ b/polly/lib/CodeGen/IRBuilder.cpp
@@ -26,24 +26,22 @@ static const int MaxArraysInAliasScops = 10;
///
/// The MDNode looks like this (if arg0/arg1 are not null):
///
-/// '!n = metadata !{metadata !n, arg0, arg1}'
+/// '!n = distinct !{!n, arg0, arg1}'
///
/// @return The self referencing id metadata node.
static MDNode *getID(LLVMContext &Ctx, Metadata *arg0 = nullptr,
Metadata *arg1 = nullptr) {
MDNode *ID;
SmallVector<Metadata *, 3> Args;
- // Use a temporary node to safely create a unique pointer for the first arg.
- auto TempNode = MDNode::getTemporary(Ctx, None);
// Reserve operand 0 for loop id self reference.
- Args.push_back(TempNode.get());
+ Args.push_back(nullptr);
if (arg0)
Args.push_back(arg0);
if (arg1)
Args.push_back(arg1);
- ID = MDNode::get(Ctx, Args);
+ ID = MDNode::getDistinct(Ctx, Args);
ID->replaceOperandWith(0, ID);
return ID;
}
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