[llvm-branch-commits] [llvm] [polly] [NFC][Load] Make `ScanFrom` required parameters (PR #100789)
Vitaly Buka via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Fri Jul 26 11:59:46 PDT 2024
https://github.com/vitalybuka updated https://github.com/llvm/llvm-project/pull/100789
>From ffe82da6043bd9f15abf4ab8075b1cf8f84fb2fa Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Fri, 26 Jul 2024 11:18:44 -0700
Subject: [PATCH 1/2] [NFC][Load] Find better place for
`mustSuppressSpeculation`
And extract `suppressSpeculativeLoadForSanitizers`.
Pull Request: https://github.com/llvm/llvm-project/pull/100794
---
llvm/include/llvm/Analysis/Loads.h | 7 +++++++
llvm/include/llvm/Analysis/ValueTracking.h | 7 -------
llvm/lib/Analysis/Loads.cpp | 13 +++++++++++++
llvm/lib/Analysis/ValueTracking.cpp | 11 -----------
4 files changed, 20 insertions(+), 18 deletions(-)
diff --git a/llvm/include/llvm/Analysis/Loads.h b/llvm/include/llvm/Analysis/Loads.h
index 33e817828b754..38f86f77b4158 100644
--- a/llvm/include/llvm/Analysis/Loads.h
+++ b/llvm/include/llvm/Analysis/Loads.h
@@ -106,6 +106,13 @@ bool isSafeToLoadUnconditionally(Value *V, Type *Ty, Align Alignment,
const DominatorTree *DT = nullptr,
const TargetLibraryInfo *TLI = nullptr);
+/// Return true if speculation of the given load must be suppressed to avoid
+/// ordering or interfering with an active sanitizer. If not suppressed,
+/// dereferenceability and alignment must be proven separately. Note: This
+/// is only needed for raw reasoning; if you use the interface below
+/// (isSafeToSpeculativelyExecute), this is handled internally.
+bool mustSuppressSpeculation(const LoadInst &LI);
+
/// The default number of maximum instructions to scan in the block, used by
/// FindAvailableLoadedValue().
extern cl::opt<unsigned> DefMaxInstsToScan;
diff --git a/llvm/include/llvm/Analysis/ValueTracking.h b/llvm/include/llvm/Analysis/ValueTracking.h
index 5ef6e43483906..96fa16970584d 100644
--- a/llvm/include/llvm/Analysis/ValueTracking.h
+++ b/llvm/include/llvm/Analysis/ValueTracking.h
@@ -792,13 +792,6 @@ bool onlyUsedByLifetimeMarkers(const Value *V);
/// droppable instructions.
bool onlyUsedByLifetimeMarkersOrDroppableInsts(const Value *V);
-/// Return true if speculation of the given load must be suppressed to avoid
-/// ordering or interfering with an active sanitizer. If not suppressed,
-/// dereferenceability and alignment must be proven separately. Note: This
-/// is only needed for raw reasoning; if you use the interface below
-/// (isSafeToSpeculativelyExecute), this is handled internally.
-bool mustSuppressSpeculation(const LoadInst &LI);
-
/// Return true if the instruction does not have any effects besides
/// calculating the result and does not have undefined behavior.
///
diff --git a/llvm/lib/Analysis/Loads.cpp b/llvm/lib/Analysis/Loads.cpp
index 61c6aa5e5a3eb..1704f0db4c599 100644
--- a/llvm/lib/Analysis/Loads.cpp
+++ b/llvm/lib/Analysis/Loads.cpp
@@ -345,6 +345,19 @@ bool llvm::isDereferenceableAndAlignedInLoop(LoadInst *LI, Loop *L,
HeaderFirstNonPHI, AC, &DT);
}
+static bool suppressSpeculativeLoadForSanitizers(const Instruction &CtxI) {
+ const Function &F = *CtxI.getFunction();
+ // Speculative load may create a race that did not exist in the source.
+ return F.hasFnAttribute(Attribute::SanitizeThread) ||
+ // Speculative load may load data from dirty regions.
+ F.hasFnAttribute(Attribute::SanitizeAddress) ||
+ F.hasFnAttribute(Attribute::SanitizeHWAddress);
+}
+
+bool llvm::mustSuppressSpeculation(const LoadInst &LI) {
+ return !LI.isUnordered() || suppressSpeculativeLoadForSanitizers(LI);
+}
+
/// Check if executing a load of this pointer value cannot trap.
///
/// If DT and ScanFrom are specified this method performs context-sensitive
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index bfd26fadd237b..497f6eafd22d8 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -6798,17 +6798,6 @@ bool llvm::onlyUsedByLifetimeMarkersOrDroppableInsts(const Value *V) {
V, /* AllowLifetime */ true, /* AllowDroppable */ true);
}
-bool llvm::mustSuppressSpeculation(const LoadInst &LI) {
- if (!LI.isUnordered())
- return true;
- const Function &F = *LI.getFunction();
- // Speculative load may create a race that did not exist in the source.
- return F.hasFnAttribute(Attribute::SanitizeThread) ||
- // Speculative load may load data from dirty regions.
- F.hasFnAttribute(Attribute::SanitizeAddress) ||
- F.hasFnAttribute(Attribute::SanitizeHWAddress);
-}
-
bool llvm::isSafeToSpeculativelyExecute(const Instruction *Inst,
const Instruction *CtxI,
AssumptionCache *AC,
>From 403561bd1ef32d20dc73a0e89328c9467d6f4a25 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Fri, 26 Jul 2024 11:04:32 -0700
Subject: [PATCH 2/2] [NFC][Load] Make `ScanFrom` required parameters
In #100773 we will go conservative for sanitizers,
so it's better to pinpoint location consciously.
Pull Request: https://github.com/llvm/llvm-project/pull/100789
---
llvm/include/llvm/Analysis/Loads.h | 6 ++----
polly/lib/Analysis/ScopBuilder.cpp | 2 +-
polly/lib/Analysis/ScopDetection.cpp | 3 ++-
3 files changed, 5 insertions(+), 6 deletions(-)
diff --git a/llvm/include/llvm/Analysis/Loads.h b/llvm/include/llvm/Analysis/Loads.h
index 38f86f77b4158..1f01ff7027fa9 100644
--- a/llvm/include/llvm/Analysis/Loads.h
+++ b/llvm/include/llvm/Analysis/Loads.h
@@ -69,8 +69,7 @@ bool isDereferenceableAndAlignedPointer(const Value *V, Align Alignment,
/// quick local scan of the basic block containing ScanFrom, to determine if
/// the address is already accessed.
bool isSafeToLoadUnconditionally(Value *V, Align Alignment, const APInt &Size,
- const DataLayout &DL,
- Instruction *ScanFrom = nullptr,
+ const DataLayout &DL, Instruction *ScanFrom,
AssumptionCache *AC = nullptr,
const DominatorTree *DT = nullptr,
const TargetLibraryInfo *TLI = nullptr);
@@ -100,8 +99,7 @@ bool isDereferenceableReadOnlyLoop(Loop *L, ScalarEvolution *SE,
/// quick local scan of the basic block containing ScanFrom, to determine if
/// the address is already accessed.
bool isSafeToLoadUnconditionally(Value *V, Type *Ty, Align Alignment,
- const DataLayout &DL,
- Instruction *ScanFrom = nullptr,
+ const DataLayout &DL, Instruction *ScanFrom,
AssumptionCache *AC = nullptr,
const DominatorTree *DT = nullptr,
const TargetLibraryInfo *TLI = nullptr);
diff --git a/polly/lib/Analysis/ScopBuilder.cpp b/polly/lib/Analysis/ScopBuilder.cpp
index d594823410f5f..0b9a1a916e1c1 100644
--- a/polly/lib/Analysis/ScopBuilder.cpp
+++ b/polly/lib/Analysis/ScopBuilder.cpp
@@ -2770,7 +2770,7 @@ isl::set ScopBuilder::getNonHoistableCtx(MemoryAccess *Access,
auto &DL = scop->getFunction().getDataLayout();
if (isSafeToLoadUnconditionally(LI->getPointerOperand(), LI->getType(),
- LI->getAlign(), DL)) {
+ LI->getAlign(), DL, nullptr)) {
SafeToLoad = isl::set::universe(AccessRelation.get_space().range());
} else if (BB != LI->getParent()) {
// Skip accesses in non-affine subregions as they might not be executed
diff --git a/polly/lib/Analysis/ScopDetection.cpp b/polly/lib/Analysis/ScopDetection.cpp
index eab7bd83e6a4e..79db3965de023 100644
--- a/polly/lib/Analysis/ScopDetection.cpp
+++ b/polly/lib/Analysis/ScopDetection.cpp
@@ -490,7 +490,8 @@ bool ScopDetection::onlyValidRequiredInvariantLoads(
for (auto NonAffineRegion : Context.NonAffineSubRegionSet) {
if (isSafeToLoadUnconditionally(Load->getPointerOperand(),
- Load->getType(), Load->getAlign(), DL))
+ Load->getType(), Load->getAlign(), DL,
+ nullptr))
continue;
if (NonAffineRegion->contains(Load) &&
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