[llvm] (Draft) [SimplifyIndVar] Push more users to worklist for simplifyUsers (PR #93598)
via llvm-commits
llvm-commits at lists.llvm.org
Wed Jun 5 00:14:27 PDT 2024
https://github.com/v01dXYZ updated https://github.com/llvm/llvm-project/pull/93598
>From 4306f3b479701ce410ce2fb9b990fe80ebff3f8d Mon Sep 17 00:00:00 2001
From: v01dxyz <v01dxyz at v01d.xyz>
Date: Mon, 27 May 2024 11:31:21 +0200
Subject: [PATCH 1/6] (Draft) [SimplifyIndVar] Push more users to worklist for
simplifyUsers
Instead of considering only users that are inside the loop,
consider all the users with parent dominated by the loop header.
---
llvm/lib/Transforms/Utils/SimplifyIndVar.cpp | 22 ++++++++++----------
1 file changed, 11 insertions(+), 11 deletions(-)
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index 912c02c2ed3ae..decdf27125f58 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -840,9 +840,9 @@ bool SimplifyIndvar::strengthenRightShift(BinaryOperator *BO,
/// Add all uses of Def to the current IV's worklist.
static void pushIVUsers(
- Instruction *Def, Loop *L,
- SmallPtrSet<Instruction*,16> &Simplified,
- SmallVectorImpl< std::pair<Instruction*,Instruction*> > &SimpleIVUsers) {
+ Instruction *Def, Loop *L, DominatorTree *DT,
+ SmallPtrSet<Instruction *, 16> &Simplified,
+ SmallVectorImpl<std::pair<Instruction *, Instruction *>> &SimpleIVUsers) {
for (User *U : Def->users()) {
Instruction *UI = cast<Instruction>(U);
@@ -854,9 +854,9 @@ static void pushIVUsers(
if (UI == Def)
continue;
- // Only change the current Loop, do not change the other parts (e.g. other
- // Loops).
- if (!L->contains(UI))
+ // Avoid adding Defs that SCEV expand to themselves, e.g. the LoopPhis
+ // of the outter loops.
+ if (!DT->dominates(L->getHeader(), UI->getParent()))
continue;
// Do not push the same instruction more than once.
@@ -913,7 +913,7 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
// Push users of the current LoopPhi. In rare cases, pushIVUsers may be
// called multiple times for the same LoopPhi. This is the proper thing to
// do for loop header phis that use each other.
- pushIVUsers(CurrIV, L, Simplified, SimpleIVUsers);
+ pushIVUsers(CurrIV, L, DT, Simplified, SimpleIVUsers);
while (!SimpleIVUsers.empty()) {
std::pair<Instruction*, Instruction*> UseOper =
@@ -960,7 +960,7 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
continue;
if (eliminateIVUser(UseInst, IVOperand)) {
- pushIVUsers(IVOperand, L, Simplified, SimpleIVUsers);
+ pushIVUsers(IVOperand, L, DT, Simplified, SimpleIVUsers);
continue;
}
@@ -968,14 +968,14 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
if (strengthenBinaryOp(BO, IVOperand)) {
// re-queue uses of the now modified binary operator and fall
// through to the checks that remain.
- pushIVUsers(IVOperand, L, Simplified, SimpleIVUsers);
+ pushIVUsers(IVOperand, L, DT, Simplified, SimpleIVUsers);
}
}
// Try to use integer induction for FPToSI of float induction directly.
if (replaceFloatIVWithIntegerIV(UseInst)) {
// Re-queue the potentially new direct uses of IVOperand.
- pushIVUsers(IVOperand, L, Simplified, SimpleIVUsers);
+ pushIVUsers(IVOperand, L, DT, Simplified, SimpleIVUsers);
continue;
}
@@ -985,7 +985,7 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
continue;
}
if (isSimpleIVUser(UseInst, L, SE)) {
- pushIVUsers(UseInst, L, Simplified, SimpleIVUsers);
+ pushIVUsers(UseInst, L, DT, Simplified, SimpleIVUsers);
}
}
}
>From c55695b44b98640c7c5eaf04b7895c2888407b13 Mon Sep 17 00:00:00 2001
From: v01dxyz <v01dxyz at v01d.xyz>
Date: Fri, 31 May 2024 00:22:58 +0200
Subject: [PATCH 2/6] (Draft) [SimplifyIndvar] Dirty fixes to allow out of loop
Users
---
llvm/lib/Transforms/Utils/SimplifyIndVar.cpp | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index decdf27125f58..18257373d678f 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -511,6 +511,7 @@ bool SimplifyIndvar::eliminateTrunc(TruncInst *TI) {
ICmpInst *ICI = dyn_cast<ICmpInst>(U);
if (!ICI) return false;
assert(L->contains(ICI->getParent()) && "LCSSA form broken?");
+ // assert(L->contains(ICI->getParent()) && "LCSSA form broken?");
if (!(ICI->getOperand(0) == TI && L->isLoopInvariant(ICI->getOperand(1))) &&
!(ICI->getOperand(1) == TI && L->isLoopInvariant(ICI->getOperand(0))))
return false;
@@ -942,7 +943,8 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
if ((isa<PtrToIntInst>(UseInst)) || (isa<TruncInst>(UseInst)))
for (Use &U : UseInst->uses()) {
Instruction *User = cast<Instruction>(U.getUser());
- if (replaceIVUserWithLoopInvariant(User))
+ if (DT->dominates(L->getHeader(), User->getParent()) &&
+ replaceIVUserWithLoopInvariant(User))
break; // done replacing
}
>From 6ae58f1e0c0c86b870f49035be1686b87c80554a Mon Sep 17 00:00:00 2001
From: v01dxyz <v01dxyz at v01d.xyz>
Date: Mon, 3 Jun 2024 10:27:55 +0200
Subject: [PATCH 3/6] (Draft) [SimplifyIndvar] Add a parameter to limit
processing out-of-loop users
---
llvm/lib/Transforms/Utils/SimplifyIndVar.cpp | 52 ++++++++++++++------
1 file changed, 37 insertions(+), 15 deletions(-)
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index 18257373d678f..7023b2f01696c 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -62,6 +62,12 @@ namespace {
bool Changed = false;
bool RunUnswitching = false;
+ // When following the def-use chains, it can go outside the loop.
+ // Stop processing the chain if it encounters
+ // MaxSuccessiveOutOfLoop successive out-of-loop users.
+ // If null, traverse the full chain.
+ std::optional<unsigned> MaxSuccessiveOutOfLoop = 0;
+
public:
SimplifyIndvar(Loop *Loop, ScalarEvolution *SE, DominatorTree *DT,
LoopInfo *LI, const TargetTransformInfo *TTI,
@@ -840,10 +846,13 @@ bool SimplifyIndvar::strengthenRightShift(BinaryOperator *BO,
}
/// Add all uses of Def to the current IV's worklist.
-static void pushIVUsers(
- Instruction *Def, Loop *L, DominatorTree *DT,
- SmallPtrSet<Instruction *, 16> &Simplified,
- SmallVectorImpl<std::pair<Instruction *, Instruction *>> &SimpleIVUsers) {
+static void
+pushIVUsers(Instruction *Def, Loop *L, DominatorTree *DT,
+ SmallPtrSet<Instruction *, 16> &Simplified,
+ SmallVectorImpl<std::tuple<Instruction *, Instruction *, unsigned>>
+ &SimpleIVUsers,
+ unsigned OutOfLoopChainCounter,
+ std::optional<unsigned> MaxSuccessiveOutOfLoop) {
for (User *U : Def->users()) {
Instruction *UI = cast<Instruction>(U);
@@ -864,7 +873,13 @@ static void pushIVUsers(
if (!Simplified.insert(UI).second)
continue;
- SimpleIVUsers.push_back(std::make_pair(UI, Def));
+ // reset depth if we go back inside the loop.
+ if (L->contains(UI) || !MaxSuccessiveOutOfLoop) {
+ SimpleIVUsers.push_back(std::make_tuple(UI, Def, 0));
+ } else if (OutOfLoopChainCounter + 1 <= *MaxSuccessiveOutOfLoop) {
+ SimpleIVUsers.push_back(
+ std::make_tuple(UI, Def, OutOfLoopChainCounter + 1));
+ }
}
}
@@ -909,17 +924,21 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
SmallPtrSet<Instruction*,16> Simplified;
// Use-def pairs if IV users waiting to be processed for CurrIV.
- SmallVector<std::pair<Instruction*, Instruction*>, 8> SimpleIVUsers;
+ SmallVector<std::tuple<Instruction *, Instruction *, unsigned>, 8>
+ SimpleIVUsers;
// Push users of the current LoopPhi. In rare cases, pushIVUsers may be
// called multiple times for the same LoopPhi. This is the proper thing to
// do for loop header phis that use each other.
- pushIVUsers(CurrIV, L, DT, Simplified, SimpleIVUsers);
+ pushIVUsers(CurrIV, L, DT, Simplified, SimpleIVUsers, 0,
+ MaxSuccessiveOutOfLoop);
while (!SimpleIVUsers.empty()) {
- std::pair<Instruction*, Instruction*> UseOper =
- SimpleIVUsers.pop_back_val();
- Instruction *UseInst = UseOper.first;
+ Instruction *UseInst, *IVOperand;
+ unsigned OutOfLoopChainCounter;
+
+ std::tie(UseInst, IVOperand, OutOfLoopChainCounter) =
+ SimpleIVUsers.pop_back_val();
// If a user of the IndVar is trivially dead, we prefer just to mark it dead
// rather than try to do some complex analysis or transformation (such as
@@ -948,7 +967,6 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
break; // done replacing
}
- Instruction *IVOperand = UseOper.second;
for (unsigned N = 0; IVOperand; ++N) {
assert(N <= Simplified.size() && "runaway iteration");
(void) N;
@@ -962,7 +980,8 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
continue;
if (eliminateIVUser(UseInst, IVOperand)) {
- pushIVUsers(IVOperand, L, DT, Simplified, SimpleIVUsers);
+ pushIVUsers(IVOperand, L, DT, Simplified, SimpleIVUsers,
+ OutOfLoopChainCounter, MaxSuccessiveOutOfLoop);
continue;
}
@@ -970,14 +989,16 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
if (strengthenBinaryOp(BO, IVOperand)) {
// re-queue uses of the now modified binary operator and fall
// through to the checks that remain.
- pushIVUsers(IVOperand, L, DT, Simplified, SimpleIVUsers);
+ pushIVUsers(IVOperand, L, DT, Simplified, SimpleIVUsers,
+ OutOfLoopChainCounter, MaxSuccessiveOutOfLoop);
}
}
// Try to use integer induction for FPToSI of float induction directly.
if (replaceFloatIVWithIntegerIV(UseInst)) {
// Re-queue the potentially new direct uses of IVOperand.
- pushIVUsers(IVOperand, L, DT, Simplified, SimpleIVUsers);
+ pushIVUsers(IVOperand, L, DT, Simplified, SimpleIVUsers,
+ OutOfLoopChainCounter, MaxSuccessiveOutOfLoop);
continue;
}
@@ -987,7 +1008,8 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
continue;
}
if (isSimpleIVUser(UseInst, L, SE)) {
- pushIVUsers(UseInst, L, DT, Simplified, SimpleIVUsers);
+ pushIVUsers(UseInst, L, DT, Simplified, SimpleIVUsers,
+ OutOfLoopChainCounter, MaxSuccessiveOutOfLoop);
}
}
}
>From ddcf5916b6e1f86f2a333a0f3454aee7d30f83b5 Mon Sep 17 00:00:00 2001
From: v01dxyz <v01dxyz at v01d.xyz>
Date: Mon, 3 Jun 2024 13:43:47 +0200
Subject: [PATCH 4/6] (Draft) TMP Add MaxSuccessiveOutOfLoop to IndVarSimplify
to squash
---
.../llvm/Transforms/Utils/SimplifyIndVar.h | 11 ++++----
llvm/lib/Transforms/Scalar/IndVarSimplify.cpp | 9 +++++--
llvm/lib/Transforms/Utils/SimplifyIndVar.cpp | 27 ++++++++++---------
3 files changed, 26 insertions(+), 21 deletions(-)
diff --git a/llvm/include/llvm/Transforms/Utils/SimplifyIndVar.h b/llvm/include/llvm/Transforms/Utils/SimplifyIndVar.h
index bd1718dd8cad7..2fdd9fefd3980 100644
--- a/llvm/include/llvm/Transforms/Utils/SimplifyIndVar.h
+++ b/llvm/include/llvm/Transforms/Utils/SimplifyIndVar.h
@@ -52,12 +52,11 @@ class IVVisitor {
/// where the first entry indicates that the function makes changes and the
/// second entry indicates that it introduced new opportunities for loop
/// unswitching.
-std::pair<bool, bool> simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE,
- DominatorTree *DT, LoopInfo *LI,
- const TargetTransformInfo *TTI,
- SmallVectorImpl<WeakTrackingVH> &Dead,
- SCEVExpander &Rewriter,
- IVVisitor *V = nullptr);
+std::pair<bool, bool>
+simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT,
+ LoopInfo *LI, const TargetTransformInfo *TTI,
+ SmallVectorImpl<WeakTrackingVH> &Dead, SCEVExpander &Rewriter,
+ unsigned MaxSuccessiveOutOfLoop = 1, IVVisitor *V = nullptr);
/// SimplifyLoopIVs - Simplify users of induction variables within this
/// loop. This does not actually change or add IVs.
diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
index dd7c89034ca09..0d62d0c1dc4d9 100644
--- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -124,6 +124,10 @@ static cl::opt<bool>
AllowIVWidening("indvars-widen-indvars", cl::Hidden, cl::init(true),
cl::desc("Allow widening of indvars to eliminate s/zext"));
+static cl::opt<unsigned> MaxSuccessiveOutOfLoop(
+ "indvars-max-successive-out-of-loop", cl::Hidden, cl::init(1),
+ cl::desc("Number of successive out-of-loop users before stopping"));
+
namespace {
class IndVarSimplify {
@@ -624,8 +628,9 @@ bool IndVarSimplify::simplifyAndExtend(Loop *L,
// Information about sign/zero extensions of CurrIV.
IndVarSimplifyVisitor Visitor(CurrIV, SE, TTI, DT);
- const auto &[C, U] = simplifyUsersOfIV(CurrIV, SE, DT, LI, TTI, DeadInsts,
- Rewriter, &Visitor);
+ const auto &[C, U] =
+ simplifyUsersOfIV(CurrIV, SE, DT, LI, TTI, DeadInsts, Rewriter,
+ MaxSuccessiveOutOfLoop, &Visitor);
Changed |= C;
RunUnswitching |= U;
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index 7023b2f01696c..4a5a153b1041a 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -66,15 +66,16 @@ namespace {
// Stop processing the chain if it encounters
// MaxSuccessiveOutOfLoop successive out-of-loop users.
// If null, traverse the full chain.
- std::optional<unsigned> MaxSuccessiveOutOfLoop = 0;
+ unsigned MaxSuccessiveOutOfLoop;
public:
SimplifyIndvar(Loop *Loop, ScalarEvolution *SE, DominatorTree *DT,
LoopInfo *LI, const TargetTransformInfo *TTI,
SCEVExpander &Rewriter,
- SmallVectorImpl<WeakTrackingVH> &Dead)
+ SmallVectorImpl<WeakTrackingVH> &Dead,
+ unsigned MaxSuccessiveOutOfLoop = 1)
: L(Loop), LI(LI), SE(SE), DT(DT), TTI(TTI), Rewriter(Rewriter),
- DeadInsts(Dead) {
+ DeadInsts(Dead), MaxSuccessiveOutOfLoop(MaxSuccessiveOutOfLoop) {
assert(LI && "IV simplification requires LoopInfo");
}
@@ -851,8 +852,7 @@ pushIVUsers(Instruction *Def, Loop *L, DominatorTree *DT,
SmallPtrSet<Instruction *, 16> &Simplified,
SmallVectorImpl<std::tuple<Instruction *, Instruction *, unsigned>>
&SimpleIVUsers,
- unsigned OutOfLoopChainCounter,
- std::optional<unsigned> MaxSuccessiveOutOfLoop) {
+ unsigned OutOfLoopChainCounter, unsigned MaxSuccessiveOutOfLoop) {
for (User *U : Def->users()) {
Instruction *UI = cast<Instruction>(U);
@@ -874,9 +874,10 @@ pushIVUsers(Instruction *Def, Loop *L, DominatorTree *DT,
continue;
// reset depth if we go back inside the loop.
- if (L->contains(UI) || !MaxSuccessiveOutOfLoop) {
+ if (L->contains(UI)) {
SimpleIVUsers.push_back(std::make_tuple(UI, Def, 0));
- } else if (OutOfLoopChainCounter + 1 <= *MaxSuccessiveOutOfLoop) {
+ } else if (!MaxSuccessiveOutOfLoop ||
+ OutOfLoopChainCounter + 1 < MaxSuccessiveOutOfLoop) {
SimpleIVUsers.push_back(
std::make_tuple(UI, Def, OutOfLoopChainCounter + 1));
}
@@ -1023,13 +1024,13 @@ void IVVisitor::anchor() { }
/// Returns a pair where the first entry indicates that the function makes
/// changes and the second entry indicates that it introduced new opportunities
/// for loop unswitching.
-std::pair<bool, bool> simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE,
- DominatorTree *DT, LoopInfo *LI,
- const TargetTransformInfo *TTI,
- SmallVectorImpl<WeakTrackingVH> &Dead,
- SCEVExpander &Rewriter, IVVisitor *V) {
+std::pair<bool, bool>
+simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT,
+ LoopInfo *LI, const TargetTransformInfo *TTI,
+ SmallVectorImpl<WeakTrackingVH> &Dead, SCEVExpander &Rewriter,
+ unsigned MaxSuccessiveOutOfLoop, IVVisitor *V) {
SimplifyIndvar SIV(LI->getLoopFor(CurrIV->getParent()), SE, DT, LI, TTI,
- Rewriter, Dead);
+ Rewriter, Dead, MaxSuccessiveOutOfLoop);
SIV.simplifyUsers(CurrIV, V);
return {SIV.hasChanged(), SIV.runUnswitching()};
}
>From 6787cdb2aec57a313c1b7d9e5d66c73928f09ac7 Mon Sep 17 00:00:00 2001
From: v01dxyz <v01dxyz at v01d.xyz>
Date: Mon, 3 Jun 2024 15:03:53 +0200
Subject: [PATCH 5/6] (Draft) TMP Depth with block instead of instruction
to squash
---
.../llvm/Transforms/Utils/SimplifyIndVar.h | 2 +-
llvm/lib/Transforms/Scalar/IndVarSimplify.cpp | 10 ++--
llvm/lib/Transforms/Utils/SimplifyIndVar.cpp | 49 +++++++++----------
3 files changed, 30 insertions(+), 31 deletions(-)
diff --git a/llvm/include/llvm/Transforms/Utils/SimplifyIndVar.h b/llvm/include/llvm/Transforms/Utils/SimplifyIndVar.h
index 2fdd9fefd3980..dbf2bdd18467d 100644
--- a/llvm/include/llvm/Transforms/Utils/SimplifyIndVar.h
+++ b/llvm/include/llvm/Transforms/Utils/SimplifyIndVar.h
@@ -56,7 +56,7 @@ std::pair<bool, bool>
simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT,
LoopInfo *LI, const TargetTransformInfo *TTI,
SmallVectorImpl<WeakTrackingVH> &Dead, SCEVExpander &Rewriter,
- unsigned MaxSuccessiveOutOfLoop = 1, IVVisitor *V = nullptr);
+ unsigned MaxDepthOutOfLoop = 1, IVVisitor *V = nullptr);
/// SimplifyLoopIVs - Simplify users of induction variables within this
/// loop. This does not actually change or add IVs.
diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
index 0d62d0c1dc4d9..ea0f7a986e4b9 100644
--- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -124,9 +124,11 @@ static cl::opt<bool>
AllowIVWidening("indvars-widen-indvars", cl::Hidden, cl::init(true),
cl::desc("Allow widening of indvars to eliminate s/zext"));
-static cl::opt<unsigned> MaxSuccessiveOutOfLoop(
- "indvars-max-successive-out-of-loop", cl::Hidden, cl::init(1),
- cl::desc("Number of successive out-of-loop users before stopping"));
+static cl::opt<unsigned> MaxDepthOutOfLoop(
+ "indvars-max-depth-out-of-loop", cl::Hidden, cl::init(1),
+ cl::desc(
+ "Strict upper bound for the number of successive out-of-loop blocks "
+ "when traversing use-def chains. 0 enables full traversal"));
namespace {
@@ -630,7 +632,7 @@ bool IndVarSimplify::simplifyAndExtend(Loop *L,
const auto &[C, U] =
simplifyUsersOfIV(CurrIV, SE, DT, LI, TTI, DeadInsts, Rewriter,
- MaxSuccessiveOutOfLoop, &Visitor);
+ MaxDepthOutOfLoop, &Visitor);
Changed |= C;
RunUnswitching |= U;
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index 4a5a153b1041a..c840491f5b7df 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -63,19 +63,17 @@ namespace {
bool RunUnswitching = false;
// When following the def-use chains, it can go outside the loop.
- // Stop processing the chain if it encounters
- // MaxSuccessiveOutOfLoop successive out-of-loop users.
- // If null, traverse the full chain.
- unsigned MaxSuccessiveOutOfLoop;
+ // Strict upper bound on number of traversed out-of-loop blocks.
+ unsigned MaxDepthOutOfLoop;
public:
SimplifyIndvar(Loop *Loop, ScalarEvolution *SE, DominatorTree *DT,
LoopInfo *LI, const TargetTransformInfo *TTI,
SCEVExpander &Rewriter,
SmallVectorImpl<WeakTrackingVH> &Dead,
- unsigned MaxSuccessiveOutOfLoop = 1)
+ unsigned MaxDepthOutOfLoop = 1)
: L(Loop), LI(LI), SE(SE), DT(DT), TTI(TTI), Rewriter(Rewriter),
- DeadInsts(Dead), MaxSuccessiveOutOfLoop(MaxSuccessiveOutOfLoop) {
+ DeadInsts(Dead), MaxDepthOutOfLoop(MaxDepthOutOfLoop) {
assert(LI && "IV simplification requires LoopInfo");
}
@@ -852,7 +850,7 @@ pushIVUsers(Instruction *Def, Loop *L, DominatorTree *DT,
SmallPtrSet<Instruction *, 16> &Simplified,
SmallVectorImpl<std::tuple<Instruction *, Instruction *, unsigned>>
&SimpleIVUsers,
- unsigned OutOfLoopChainCounter, unsigned MaxSuccessiveOutOfLoop) {
+ unsigned OutOfLoopChainCounter) {
for (User *U : Def->users()) {
Instruction *UI = cast<Instruction>(U);
@@ -874,13 +872,11 @@ pushIVUsers(Instruction *Def, Loop *L, DominatorTree *DT,
continue;
// reset depth if we go back inside the loop.
- if (L->contains(UI)) {
- SimpleIVUsers.push_back(std::make_tuple(UI, Def, 0));
- } else if (!MaxSuccessiveOutOfLoop ||
- OutOfLoopChainCounter + 1 < MaxSuccessiveOutOfLoop) {
- SimpleIVUsers.push_back(
- std::make_tuple(UI, Def, OutOfLoopChainCounter + 1));
- }
+ SimpleIVUsers.push_back(std::make_tuple(
+ UI, Def,
+ L->contains(UI)
+ ? 0
+ : OutOfLoopChainCounter + (UI->getParent() != Def->getParent())));
}
}
@@ -931,8 +927,7 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
// Push users of the current LoopPhi. In rare cases, pushIVUsers may be
// called multiple times for the same LoopPhi. This is the proper thing to
// do for loop header phis that use each other.
- pushIVUsers(CurrIV, L, DT, Simplified, SimpleIVUsers, 0,
- MaxSuccessiveOutOfLoop);
+ pushIVUsers(CurrIV, L, DT, Simplified, SimpleIVUsers, 0);
while (!SimpleIVUsers.empty()) {
Instruction *UseInst, *IVOperand;
@@ -980,26 +975,28 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
if (!IVOperand)
continue;
- if (eliminateIVUser(UseInst, IVOperand)) {
+ bool IsLowerMaxOutOfLoop =
+ !MaxDepthOutOfLoop || (OutOfLoopChainCounter < MaxDepthOutOfLoop);
+ if (eliminateIVUser(UseInst, IVOperand) && IsLowerMaxOutOfLoop) {
pushIVUsers(IVOperand, L, DT, Simplified, SimpleIVUsers,
- OutOfLoopChainCounter, MaxSuccessiveOutOfLoop);
+ OutOfLoopChainCounter);
continue;
}
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(UseInst)) {
- if (strengthenBinaryOp(BO, IVOperand)) {
+ if (strengthenBinaryOp(BO, IVOperand) && IsLowerMaxOutOfLoop) {
// re-queue uses of the now modified binary operator and fall
// through to the checks that remain.
pushIVUsers(IVOperand, L, DT, Simplified, SimpleIVUsers,
- OutOfLoopChainCounter, MaxSuccessiveOutOfLoop);
+ OutOfLoopChainCounter);
}
}
// Try to use integer induction for FPToSI of float induction directly.
- if (replaceFloatIVWithIntegerIV(UseInst)) {
+ if (replaceFloatIVWithIntegerIV(UseInst) && IsLowerMaxOutOfLoop) {
// Re-queue the potentially new direct uses of IVOperand.
pushIVUsers(IVOperand, L, DT, Simplified, SimpleIVUsers,
- OutOfLoopChainCounter, MaxSuccessiveOutOfLoop);
+ OutOfLoopChainCounter);
continue;
}
@@ -1008,9 +1005,9 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
V->visitCast(Cast);
continue;
}
- if (isSimpleIVUser(UseInst, L, SE)) {
+ if (IsLowerMaxOutOfLoop && isSimpleIVUser(UseInst, L, SE)) {
pushIVUsers(UseInst, L, DT, Simplified, SimpleIVUsers,
- OutOfLoopChainCounter, MaxSuccessiveOutOfLoop);
+ OutOfLoopChainCounter);
}
}
}
@@ -1028,9 +1025,9 @@ std::pair<bool, bool>
simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT,
LoopInfo *LI, const TargetTransformInfo *TTI,
SmallVectorImpl<WeakTrackingVH> &Dead, SCEVExpander &Rewriter,
- unsigned MaxSuccessiveOutOfLoop, IVVisitor *V) {
+ unsigned MaxDepthOutOfLoop, IVVisitor *V) {
SimplifyIndvar SIV(LI->getLoopFor(CurrIV->getParent()), SE, DT, LI, TTI,
- Rewriter, Dead, MaxSuccessiveOutOfLoop);
+ Rewriter, Dead, MaxDepthOutOfLoop);
SIV.simplifyUsers(CurrIV, V);
return {SIV.hasChanged(), SIV.runUnswitching()};
}
>From 165ef0d5e429b5301497445b732d82ff6bcaad07 Mon Sep 17 00:00:00 2001
From: v01dxyz <v01dxyz at v01d.xyz>
Date: Wed, 5 Jun 2024 09:11:37 +0200
Subject: [PATCH 6/6] (Draft) TMP Typo, style consistency
to squash
---
llvm/lib/Transforms/Utils/SimplifyIndVar.cpp | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index c840491f5b7df..9fcdc1a502676 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -514,9 +514,8 @@ bool SimplifyIndvar::eliminateTrunc(TruncInst *TI) {
!DT->isReachableFromEntry(cast<Instruction>(U)->getParent()))
continue;
ICmpInst *ICI = dyn_cast<ICmpInst>(U);
- if (!ICI) return false;
- assert(L->contains(ICI->getParent()) && "LCSSA form broken?");
- // assert(L->contains(ICI->getParent()) && "LCSSA form broken?");
+ if (!ICI)
+ return false;
if (!(ICI->getOperand(0) == TI && L->isLoopInvariant(ICI->getOperand(1))) &&
!(ICI->getOperand(1) == TI && L->isLoopInvariant(ICI->getOperand(0))))
return false;
@@ -930,10 +929,7 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
pushIVUsers(CurrIV, L, DT, Simplified, SimpleIVUsers, 0);
while (!SimpleIVUsers.empty()) {
- Instruction *UseInst, *IVOperand;
- unsigned OutOfLoopChainCounter;
-
- std::tie(UseInst, IVOperand, OutOfLoopChainCounter) =
+ const auto &[UseInst, IVOperand, OutOfLoopChainCounter] =
SimpleIVUsers.pop_back_val();
// If a user of the IndVar is trivially dead, we prefer just to mark it dead
More information about the llvm-commits
mailing list