[llvm] 0eeaec2 - [NFC] Refactor LoopInterchange into a loop-nest pass
Ta-Wei Tu via llvm-commits
llvm-commits at lists.llvm.org
Wed Feb 17 08:55:45 PST 2021
Author: Ta-Wei Tu
Date: 2021-02-18T00:55:38+08:00
New Revision: 0eeaec2a6d5f5758c2bbb0f47c06f769f7ae2813
URL: https://github.com/llvm/llvm-project/commit/0eeaec2a6d5f5758c2bbb0f47c06f769f7ae2813
DIFF: https://github.com/llvm/llvm-project/commit/0eeaec2a6d5f5758c2bbb0f47c06f769f7ae2813.diff
LOG: [NFC] Refactor LoopInterchange into a loop-nest pass
This is the preliminary patch of converting `LoopInterchange` pass to a loop-nest pass and has no intended functional change.
Changes that are not loop-nest related are split to D96650.
Reviewed By: Whitney
Differential Revision: https://reviews.llvm.org/D96644
Added:
llvm/test/Transforms/LoopInterchange/interchanged-loop-nest-3.ll
Modified:
llvm/include/llvm/Analysis/LoopNestAnalysis.h
llvm/include/llvm/Transforms/Scalar/LoopInterchange.h
llvm/lib/Transforms/Scalar/LoopInterchange.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/Analysis/LoopNestAnalysis.h b/llvm/include/llvm/Analysis/LoopNestAnalysis.h
index 9c4fb4dbc29b..ace17547444f 100644
--- a/llvm/include/llvm/Analysis/LoopNestAnalysis.h
+++ b/llvm/include/llvm/Analysis/LoopNestAnalysis.h
@@ -139,6 +139,11 @@ class LoopNest {
return all_of(Loops, [](const Loop *L) { return L->isRotatedForm(); });
}
+ /// Return the function to which the loop-nest belongs.
+ Function *getParent() const {
+ return Loops.front()->getHeader()->getParent();
+ }
+
StringRef getName() const { return Loops.front()->getName(); }
protected:
diff --git a/llvm/include/llvm/Transforms/Scalar/LoopInterchange.h b/llvm/include/llvm/Transforms/Scalar/LoopInterchange.h
index 9f50fc5a4127..c67a30293d2f 100644
--- a/llvm/include/llvm/Transforms/Scalar/LoopInterchange.h
+++ b/llvm/include/llvm/Transforms/Scalar/LoopInterchange.h
@@ -15,7 +15,7 @@
namespace llvm {
struct LoopInterchangePass : public PassInfoMixin<LoopInterchangePass> {
- PreservedAnalyses run(Loop &L, LoopAnalysisManager &AM,
+ PreservedAnalyses run(LoopNest &L, LoopAnalysisManager &AM,
LoopStandardAnalysisResults &AR, LPMUpdater &U);
};
diff --git a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
index 9b3f6a08f025..ff0f9f8e981b 100644
--- a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
@@ -449,7 +449,15 @@ struct LoopInterchange {
return processLoopList(populateWorklist(*L));
}
- bool isComputableLoopNest(LoopVector LoopList) {
+ bool run(LoopNest &LN) {
+ const auto &LoopList = LN.getLoops();
+ for (unsigned I = 1; I < LoopList.size(); ++I)
+ if (LoopList[I]->getParentLoop() != LoopList[I - 1])
+ return false;
+ return processLoopList(LoopList);
+ }
+
+ bool isComputableLoopNest(ArrayRef<Loop *> LoopList) {
for (Loop *L : LoopList) {
const SCEV *ExitCountOuter = SE->getBackedgeTakenCount(L);
if (isa<SCEVCouldNotCompute>(ExitCountOuter)) {
@@ -468,13 +476,13 @@ struct LoopInterchange {
return true;
}
- unsigned selectLoopForInterchange(const LoopVector &LoopList) {
+ unsigned selectLoopForInterchange(ArrayRef<Loop *> LoopList) {
// TODO: Add a better heuristic to select the loop to be interchanged based
// on the dependence matrix. Currently we select the innermost loop.
return LoopList.size() - 1;
}
- bool processLoopList(LoopVector LoopList) {
+ bool processLoopList(ArrayRef<Loop *> LoopList) {
bool Changed = false;
unsigned LoopNestDepth = LoopList.size();
if (LoopNestDepth < 2) {
@@ -515,14 +523,12 @@ struct LoopInterchange {
unsigned SelecLoopId = selectLoopForInterchange(LoopList);
// Move the selected loop outwards to the best possible position.
+ Loop *LoopToBeInterchanged = LoopList[SelecLoopId];
for (unsigned i = SelecLoopId; i > 0; i--) {
- bool Interchanged = processLoop(LoopList[i], LoopList[i - 1], i, i - 1,
- LoopNestExit, DependencyMatrix);
+ bool Interchanged = processLoop(LoopToBeInterchanged, LoopList[i - 1], i,
+ i - 1, LoopNestExit, DependencyMatrix);
if (!Interchanged)
return Changed;
- // Loops interchanged reflect the same in LoopList
- std::swap(LoopList[i - 1], LoopList[i]);
-
// Update the DependencyMatrix
interChangeDependencies(DependencyMatrix, i, i - 1);
#ifdef DUMP_DEP_MATRICIES
@@ -539,7 +545,6 @@ struct LoopInterchange {
std::vector<std::vector<char>> &DependencyMatrix) {
LLVM_DEBUG(dbgs() << "Processing InnerLoopId = " << InnerLoopId
<< " and OuterLoopId = " << OuterLoopId << "\n");
-
LoopInterchangeLegality LIL(OuterLoop, InnerLoop, SE, ORE);
if (!LIL.canInterchangeLoops(InnerLoopId, OuterLoopId, DependencyMatrix)) {
LLVM_DEBUG(dbgs() << "Not interchanging loops. Cannot prove legality.\n");
@@ -1680,14 +1685,15 @@ Pass *llvm::createLoopInterchangePass() {
return new LoopInterchangeLegacyPass();
}
-PreservedAnalyses LoopInterchangePass::run(Loop &L, LoopAnalysisManager &AM,
+PreservedAnalyses LoopInterchangePass::run(LoopNest &LN,
+ LoopAnalysisManager &AM,
LoopStandardAnalysisResults &AR,
LPMUpdater &U) {
- Function &F = *L.getHeader()->getParent();
+ Function &F = *LN.getParent();
DependenceInfo DI(&F, &AR.AA, &AR.SE, &AR.LI);
OptimizationRemarkEmitter ORE(&F);
- if (!LoopInterchange(&AR.SE, &AR.LI, &DI, &AR.DT, &ORE).run(&L))
+ if (!LoopInterchange(&AR.SE, &AR.LI, &DI, &AR.DT, &ORE).run(LN))
return PreservedAnalyses::all();
return getLoopPassPreservedAnalyses();
}
diff --git a/llvm/test/Transforms/LoopInterchange/interchanged-loop-nest-3.ll b/llvm/test/Transforms/LoopInterchange/interchanged-loop-nest-3.ll
new file mode 100644
index 000000000000..fa5db55ba5cf
--- /dev/null
+++ b/llvm/test/Transforms/LoopInterchange/interchanged-loop-nest-3.ll
@@ -0,0 +1,56 @@
+; REQUIRES: asserts
+; RUN: opt < %s -basic-aa -loop-interchange -verify-dom-info -verify-loop-info \
+; RUN: -S -debug 2>&1 | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+ at D = common global [100 x [100 x [100 x i32]]] zeroinitializer
+
+;; Test for interchange in loop nest greater than 2.
+;; for(int i=0;i<100;i++)
+;; for(int j=0;j<100;j++)
+;; for(int k=0;k<100;k++)
+;; D[k][j][i] = D[k][j][i]+t;
+
+; CHECK: Processing InnerLoopId = 2 and OuterLoopId = 1
+; CHECK: Loops interchanged.
+
+; CHECK: Processing InnerLoopId = 1 and OuterLoopId = 0
+; CHECK: Loops interchanged.
+
+define void @interchange_08(i32 %t){
+entry:
+ br label %for.cond1.preheader
+
+for.cond1.preheader: ; preds = %for.inc15, %entry
+ %i.028 = phi i32 [ 0, %entry ], [ %inc16, %for.inc15 ]
+ br label %for.cond4.preheader
+
+for.cond4.preheader: ; preds = %for.inc12, %for.cond1.preheader
+ %j.027 = phi i32 [ 0, %for.cond1.preheader ], [ %inc13, %for.inc12 ]
+ br label %for.body6
+
+for.body6: ; preds = %for.body6, %for.cond4.preheader
+ %k.026 = phi i32 [ 0, %for.cond4.preheader ], [ %inc, %for.body6 ]
+ %arrayidx8 = getelementptr inbounds [100 x [100 x [100 x i32]]], [100 x [100 x [100 x i32]]]* @D, i32 0, i32 %k.026, i32 %j.027, i32 %i.028
+ %0 = load i32, i32* %arrayidx8
+ %add = add nsw i32 %0, %t
+ store i32 %add, i32* %arrayidx8
+ %inc = add nuw nsw i32 %k.026, 1
+ %exitcond = icmp eq i32 %inc, 100
+ br i1 %exitcond, label %for.inc12, label %for.body6
+
+for.inc12: ; preds = %for.body6
+ %inc13 = add nuw nsw i32 %j.027, 1
+ %exitcond29 = icmp eq i32 %inc13, 100
+ br i1 %exitcond29, label %for.inc15, label %for.cond4.preheader
+
+for.inc15: ; preds = %for.inc12
+ %inc16 = add nuw nsw i32 %i.028, 1
+ %exitcond30 = icmp eq i32 %inc16, 100
+ br i1 %exitcond30, label %for.end17, label %for.cond1.preheader
+
+for.end17: ; preds = %for.inc15
+ ret void
+}
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