[llvm] [Loads] Support dereferenceable assumption with variable size. (PR #128436)
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Thu Jul 3 08:13:31 PDT 2025
https://github.com/fhahn updated https://github.com/llvm/llvm-project/pull/128436
>From 276dc4bbc869cffe732946100306dc09cd9b8de3 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Sun, 23 Feb 2025 21:08:40 +0000
Subject: [PATCH 1/6] [Loads] Support dereferenceable assumption with variable
size.
Update isDereferenceableAndAlignedPointer to make use of dereferenceable
assumptions with variable sizes via SCEV.
To do so, factor out the logic to check via an assumption to a helper,
and use SE to check if the access size is less than the dereferenceable
size.
---
.../llvm/Analysis/AssumeBundleQueries.h | 1 +
llvm/lib/Analysis/AssumeBundleQueries.cpp | 1 +
llvm/lib/Analysis/Loads.cpp | 53 ++-
...able-info-from-assumption-variable-size.ll | 358 ++++++++++++++++++
4 files changed, 408 insertions(+), 5 deletions(-)
create mode 100644 llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-variable-size.ll
diff --git a/llvm/include/llvm/Analysis/AssumeBundleQueries.h b/llvm/include/llvm/Analysis/AssumeBundleQueries.h
index 0d39339c4f7d7..752eb25038c7d 100644
--- a/llvm/include/llvm/Analysis/AssumeBundleQueries.h
+++ b/llvm/include/llvm/Analysis/AssumeBundleQueries.h
@@ -102,6 +102,7 @@ LLVM_ABI void fillMapFromAssume(AssumeInst &Assume,
struct RetainedKnowledge {
Attribute::AttrKind AttrKind = Attribute::None;
uint64_t ArgValue = 0;
+ Value *IRArgValue = nullptr;
Value *WasOn = nullptr;
bool operator==(RetainedKnowledge Other) const {
return AttrKind == Other.AttrKind && WasOn == Other.WasOn &&
diff --git a/llvm/lib/Analysis/AssumeBundleQueries.cpp b/llvm/lib/Analysis/AssumeBundleQueries.cpp
index 4c890a5d21b54..d1548c7db5bcd 100644
--- a/llvm/lib/Analysis/AssumeBundleQueries.cpp
+++ b/llvm/lib/Analysis/AssumeBundleQueries.cpp
@@ -114,6 +114,7 @@ llvm::getKnowledgeFromBundle(AssumeInst &Assume,
};
if (BOI.End - BOI.Begin > ABA_Argument)
Result.ArgValue = GetArgOr1(0);
+ Result.IRArgValue = getValueFromBundleOpInfo(Assume, BOI, ABA_Argument);
if (Result.AttrKind == Attribute::Alignment)
if (BOI.End - BOI.Begin > ABA_Argument + 1)
Result.ArgValue = MinAlign(Result.ArgValue, GetArgOr1(1));
diff --git a/llvm/lib/Analysis/Loads.cpp b/llvm/lib/Analysis/Loads.cpp
index 880249588f0b2..73fe2e91ab877 100644
--- a/llvm/lib/Analysis/Loads.cpp
+++ b/llvm/lib/Analysis/Loads.cpp
@@ -31,6 +31,35 @@ static bool isAligned(const Value *Base, Align Alignment,
return Base->getPointerAlignment(DL) >= Alignment;
}
+static bool isDereferenceableAndAlignedPointerViaAssumption(
+ const Value *Ptr, Align Alignment,
+ function_ref<bool(const RetainedKnowledge &RK)> CheckSize,
+ const DataLayout &DL, const Instruction *CtxI, AssumptionCache *AC,
+ const DominatorTree *DT) {
+ if (!CtxI || Ptr->canBeFreed())
+ return false;
+ /// Look through assumes to see if both dereferencability and alignment can
+ /// be proven by an assume if needed.
+ RetainedKnowledge AlignRK;
+ RetainedKnowledge DerefRK;
+ bool IsAligned = Ptr->getPointerAlignment(DL) >= Alignment;
+ return getKnowledgeForValue(
+ Ptr, {Attribute::Dereferenceable, Attribute::Alignment}, AC,
+ [&](RetainedKnowledge RK, Instruction *Assume, auto) {
+ if (!isValidAssumeForContext(Assume, CtxI, DT))
+ return false;
+ if (RK.AttrKind == Attribute::Alignment)
+ AlignRK = std::max(AlignRK, RK);
+ if (RK.AttrKind == Attribute::Dereferenceable)
+ DerefRK = std::max(DerefRK, RK);
+ IsAligned |= AlignRK && AlignRK.ArgValue >= Alignment.value();
+ if (IsAligned && DerefRK && CheckSize(DerefRK))
+ return true; // We have found what we needed so we stop looking
+ return false; // Other assumes may have better information. so
+ // keep looking
+ });
+}
+
/// Test if V is always a pointer to allocated and suitably aligned memory for
/// a simple load or store.
static bool isDereferenceableAndAlignedPointer(
@@ -199,8 +228,12 @@ static bool isDereferenceableAndAlignedPointer(
return true;
}
- // If we don't know, assume the worst.
- return false;
+ return isDereferenceableAndAlignedPointerViaAssumption(
+ V, Alignment,
+ [Size](const RetainedKnowledge &RK) {
+ return RK.ArgValue >= Size.getZExtValue();
+ },
+ DL, CtxI, AC, DT);
}
bool llvm::isDereferenceableAndAlignedPointer(
@@ -317,8 +350,8 @@ bool llvm::isDereferenceableAndAlignedInLoop(
return false;
const SCEV *MaxBECount =
- Predicates ? SE.getPredicatedConstantMaxBackedgeTakenCount(L, *Predicates)
- : SE.getConstantMaxBackedgeTakenCount(L);
+ Predicates ? SE.getPredicatedSymbolicMaxBackedgeTakenCount(L, *Predicates)
+ : SE.getSymbolicMaxBackedgeTakenCount(L);
const SCEV *BECount = Predicates
? SE.getPredicatedBackedgeTakenCount(L, *Predicates)
: SE.getBackedgeTakenCount(L);
@@ -339,9 +372,11 @@ bool llvm::isDereferenceableAndAlignedInLoop(
Value *Base = nullptr;
APInt AccessSize;
+ const SCEV *AccessSizeSCEV = nullptr;
if (const SCEVUnknown *NewBase = dyn_cast<SCEVUnknown>(AccessStart)) {
Base = NewBase->getValue();
AccessSize = MaxPtrDiff;
+ AccessSizeSCEV = PtrDiff;
} else if (auto *MinAdd = dyn_cast<SCEVAddExpr>(AccessStart)) {
if (MinAdd->getNumOperands() != 2)
return false;
@@ -365,12 +400,20 @@ bool llvm::isDereferenceableAndAlignedInLoop(
return false;
AccessSize = MaxPtrDiff + Offset->getAPInt();
+ AccessSizeSCEV = SE.getAddExpr(PtrDiff, Offset);
Base = NewBase->getValue();
} else
return false;
Instruction *HeaderFirstNonPHI = &*L->getHeader()->getFirstNonPHIIt();
- return isDereferenceableAndAlignedPointer(Base, Alignment, AccessSize, DL,
+ return isDereferenceableAndAlignedPointerViaAssumption(
+ Base, Alignment,
+ [&SE, PtrDiff](const RetainedKnowledge &RK) {
+ return SE.isKnownPredicate(CmpInst::ICMP_ULE, PtrDiff,
+ SE.getSCEV(RK.IRArgValue));
+ },
+ DL, HeaderFirstNonPHI, AC, &DT) ||
+ isDereferenceableAndAlignedPointer(Base, Alignment, AccessSize, DL,
HeaderFirstNonPHI, AC, &DT);
}
diff --git a/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-variable-size.ll b/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-variable-size.ll
new file mode 100644
index 0000000000000..d40fc53cf2d4e
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-variable-size.ll
@@ -0,0 +1,358 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --version 5
+; RUN: opt -p loop-vectorize -force-vector-width=2 -S %s | FileCheck %s
+
+declare void @llvm.assume(i1)
+
+; %a is known dereferenceable via assume for the whole loop.
+define void @deref_assumption_in_preheader_non_constant_trip_count_access_i8(ptr noalias noundef %a, ptr noalias %b, ptr noalias %c, i64 %n) nofree nosync {
+; CHECK-LABEL: define void @deref_assumption_in_preheader_non_constant_trip_count_access_i8(
+; CHECK-SAME: ptr noalias noundef [[A:%.*]], ptr noalias [[B:%.*]], ptr noalias [[C:%.*]], i64 [[N:%.*]]) #[[ATTR1:[0-9]+]] {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 4), "dereferenceable"(ptr [[A]], i64 [[N]]) ]
+; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 2
+; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK: [[VECTOR_PH]]:
+; CHECK-NEXT: [[N_MOD_VF:%.*]] = urem i64 [[N]], 2
+; CHECK-NEXT: [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
+; CHECK: [[VECTOR_BODY]]:
+; CHECK-NEXT: [[TMP0:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_LOAD_CONTINUE2:.*]] ]
+; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[B]], i64 [[TMP0]]
+; CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[TMP2]], i32 0
+; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <2 x i8>, ptr [[TMP3]], align 1
+; CHECK-NEXT: [[TMP4:%.*]] = icmp sge <2 x i8> [[WIDE_LOAD]], zeroinitializer
+; CHECK-NEXT: [[TMP15:%.*]] = xor <2 x i1> [[TMP4]], splat (i1 true)
+; CHECK-NEXT: [[TMP5:%.*]] = extractelement <2 x i1> [[TMP15]], i32 0
+; CHECK-NEXT: br i1 [[TMP5]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
+; CHECK: [[PRED_LOAD_IF]]:
+; CHECK-NEXT: [[TMP19:%.*]] = add i64 [[TMP0]], 0
+; CHECK-NEXT: [[TMP16:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 [[TMP19]]
+; CHECK-NEXT: [[TMP17:%.*]] = load i8, ptr [[TMP16]], align 1
+; CHECK-NEXT: [[TMP18:%.*]] = insertelement <2 x i8> poison, i8 [[TMP17]], i32 0
+; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE]]
+; CHECK: [[PRED_LOAD_CONTINUE]]:
+; CHECK-NEXT: [[TMP9:%.*]] = phi <2 x i8> [ poison, %[[VECTOR_BODY]] ], [ [[TMP18]], %[[PRED_LOAD_IF]] ]
+; CHECK-NEXT: [[TMP10:%.*]] = extractelement <2 x i1> [[TMP15]], i32 1
+; CHECK-NEXT: br i1 [[TMP10]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2]]
+; CHECK: [[PRED_LOAD_IF1]]:
+; CHECK-NEXT: [[TMP11:%.*]] = add i64 [[TMP0]], 1
+; CHECK-NEXT: [[TMP12:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 [[TMP11]]
+; CHECK-NEXT: [[TMP13:%.*]] = load i8, ptr [[TMP12]], align 1
+; CHECK-NEXT: [[TMP14:%.*]] = insertelement <2 x i8> [[TMP9]], i8 [[TMP13]], i32 1
+; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE2]]
+; CHECK: [[PRED_LOAD_CONTINUE2]]:
+; CHECK-NEXT: [[WIDE_LOAD1:%.*]] = phi <2 x i8> [ [[TMP9]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP14]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT: [[PREDPHI:%.*]] = select <2 x i1> [[TMP4]], <2 x i8> [[WIDE_LOAD]], <2 x i8> [[WIDE_LOAD1]]
+; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i8, ptr [[C]], i64 [[TMP0]]
+; CHECK-NEXT: [[TMP7:%.*]] = getelementptr inbounds i8, ptr [[TMP6]], i32 0
+; CHECK-NEXT: store <2 x i8> [[PREDPHI]], ptr [[TMP7]], align 1
+; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[TMP0]], 2
+; CHECK-NEXT: [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[TMP8]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK: [[MIDDLE_BLOCK]]:
+; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK: [[SCALAR_PH]]:
+; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-NEXT: br label %[[LOOP_HEADER:.*]]
+; CHECK: [[LOOP_HEADER]]:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT: [[GEP_A:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 [[IV]]
+; CHECK-NEXT: [[GEP_B:%.*]] = getelementptr inbounds i8, ptr [[B]], i64 [[IV]]
+; CHECK-NEXT: [[L_B:%.*]] = load i8, ptr [[GEP_B]], align 1
+; CHECK-NEXT: [[C_1:%.*]] = icmp sge i8 [[L_B]], 0
+; CHECK-NEXT: br i1 [[C_1]], label %[[LOOP_LATCH]], label %[[LOOP_THEN:.*]]
+; CHECK: [[LOOP_THEN]]:
+; CHECK-NEXT: [[L_A:%.*]] = load i8, ptr [[GEP_A]], align 1
+; CHECK-NEXT: br label %[[LOOP_LATCH]]
+; CHECK: [[LOOP_LATCH]]:
+; CHECK-NEXT: [[MERGE:%.*]] = phi i8 [ [[L_A]], %[[LOOP_THEN]] ], [ [[L_B]], %[[LOOP_HEADER]] ]
+; CHECK-NEXT: [[GEP_C:%.*]] = getelementptr inbounds i8, ptr [[C]], i64 [[IV]]
+; CHECK-NEXT: store i8 [[MERGE]], ptr [[GEP_C]], align 1
+; CHECK-NEXT: [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-NEXT: [[EC:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-NEXT: br i1 [[EC]], label %[[EXIT]], label %[[LOOP_HEADER]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: ret void
+;
+entry:
+ call void @llvm.assume(i1 true) [ "align"(ptr %a, i64 4), "dereferenceable"(ptr %a, i64 %n) ]
+ br label %loop.header
+
+loop.header:
+ %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+ %gep.a = getelementptr inbounds i8, ptr %a, i64 %iv
+ %gep.b = getelementptr inbounds i8, ptr %b, i64 %iv
+ %l.b = load i8, ptr %gep.b, align 1
+ %c.1 = icmp sge i8 %l.b, 0
+ br i1 %c.1, label %loop.latch, label %loop.then
+
+loop.then:
+ %l.a = load i8, ptr %gep.a, align 1
+ br label %loop.latch
+
+loop.latch:
+ %merge = phi i8 [ %l.a, %loop.then ], [ %l.b, %loop.header ]
+ %gep.c = getelementptr inbounds i8, ptr %c, i64 %iv
+ store i8 %merge, ptr %gep.c, align 1
+ %iv.next = add nuw nsw i64 %iv, 1
+ %ec = icmp eq i64 %iv.next, %n
+ br i1 %ec, label %exit, label %loop.header
+
+exit:
+ ret void
+}
+
+; %a is known dereferenceable via assume for the whole loop.
+define void @deref_assumption_in_preheader_non_constant_trip_count_access_i32(ptr noalias noundef %a, ptr noalias %b, ptr noalias %c, i64 %n) nofree nosync {
+; CHECK-LABEL: define void @deref_assumption_in_preheader_non_constant_trip_count_access_i32(
+; CHECK-SAME: ptr noalias noundef [[A:%.*]], ptr noalias [[B:%.*]], ptr noalias [[C:%.*]], i64 [[N:%.*]]) #[[ATTR1]] {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: [[MUL:%.*]] = mul nuw nsw i64 [[N]], 4
+; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 4), "dereferenceable"(ptr [[A]], i64 [[MUL]]) ]
+; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 2
+; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK: [[VECTOR_PH]]:
+; CHECK-NEXT: [[N_MOD_VF:%.*]] = urem i64 [[N]], 2
+; CHECK-NEXT: [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
+; CHECK: [[VECTOR_BODY]]:
+; CHECK-NEXT: [[TMP0:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_LOAD_CONTINUE2:.*]] ]
+; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[TMP0]]
+; CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[TMP2]], i32 0
+; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <2 x i32>, ptr [[TMP3]], align 1
+; CHECK-NEXT: [[TMP4:%.*]] = icmp sge <2 x i32> [[WIDE_LOAD]], zeroinitializer
+; CHECK-NEXT: [[TMP15:%.*]] = xor <2 x i1> [[TMP4]], splat (i1 true)
+; CHECK-NEXT: [[TMP5:%.*]] = extractelement <2 x i1> [[TMP15]], i32 0
+; CHECK-NEXT: br i1 [[TMP5]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
+; CHECK: [[PRED_LOAD_IF]]:
+; CHECK-NEXT: [[TMP19:%.*]] = add i64 [[TMP0]], 0
+; CHECK-NEXT: [[TMP16:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP19]]
+; CHECK-NEXT: [[TMP17:%.*]] = load i32, ptr [[TMP16]], align 1
+; CHECK-NEXT: [[TMP18:%.*]] = insertelement <2 x i32> poison, i32 [[TMP17]], i32 0
+; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE]]
+; CHECK: [[PRED_LOAD_CONTINUE]]:
+; CHECK-NEXT: [[TMP9:%.*]] = phi <2 x i32> [ poison, %[[VECTOR_BODY]] ], [ [[TMP18]], %[[PRED_LOAD_IF]] ]
+; CHECK-NEXT: [[TMP10:%.*]] = extractelement <2 x i1> [[TMP15]], i32 1
+; CHECK-NEXT: br i1 [[TMP10]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2]]
+; CHECK: [[PRED_LOAD_IF1]]:
+; CHECK-NEXT: [[TMP11:%.*]] = add i64 [[TMP0]], 1
+; CHECK-NEXT: [[TMP12:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP11]]
+; CHECK-NEXT: [[TMP13:%.*]] = load i32, ptr [[TMP12]], align 1
+; CHECK-NEXT: [[TMP14:%.*]] = insertelement <2 x i32> [[TMP9]], i32 [[TMP13]], i32 1
+; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE2]]
+; CHECK: [[PRED_LOAD_CONTINUE2]]:
+; CHECK-NEXT: [[WIDE_LOAD1:%.*]] = phi <2 x i32> [ [[TMP9]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP14]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT: [[PREDPHI:%.*]] = select <2 x i1> [[TMP4]], <2 x i32> [[WIDE_LOAD]], <2 x i32> [[WIDE_LOAD1]]
+; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[TMP0]]
+; CHECK-NEXT: [[TMP7:%.*]] = getelementptr inbounds i32, ptr [[TMP6]], i32 0
+; CHECK-NEXT: store <2 x i32> [[PREDPHI]], ptr [[TMP7]], align 1
+; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[TMP0]], 2
+; CHECK-NEXT: [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[TMP8]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK: [[MIDDLE_BLOCK]]:
+; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK: [[SCALAR_PH]]:
+; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-NEXT: br label %[[LOOP_HEADER:.*]]
+; CHECK: [[LOOP_HEADER]]:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT: [[GEP_A:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-NEXT: [[GEP_B:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-NEXT: [[L_B:%.*]] = load i32, ptr [[GEP_B]], align 1
+; CHECK-NEXT: [[C_1:%.*]] = icmp sge i32 [[L_B]], 0
+; CHECK-NEXT: br i1 [[C_1]], label %[[LOOP_LATCH]], label %[[LOOP_THEN:.*]]
+; CHECK: [[LOOP_THEN]]:
+; CHECK-NEXT: [[L_A:%.*]] = load i32, ptr [[GEP_A]], align 1
+; CHECK-NEXT: br label %[[LOOP_LATCH]]
+; CHECK: [[LOOP_LATCH]]:
+; CHECK-NEXT: [[MERGE:%.*]] = phi i32 [ [[L_A]], %[[LOOP_THEN]] ], [ [[L_B]], %[[LOOP_HEADER]] ]
+; CHECK-NEXT: [[GEP_C:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[IV]]
+; CHECK-NEXT: store i32 [[MERGE]], ptr [[GEP_C]], align 1
+; CHECK-NEXT: [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-NEXT: [[EC:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-NEXT: br i1 [[EC]], label %[[EXIT]], label %[[LOOP_HEADER]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: ret void
+;
+entry:
+ %mul = mul nsw nuw i64 %n, 4
+ call void @llvm.assume(i1 true) [ "align"(ptr %a, i64 4), "dereferenceable"(ptr %a, i64 %mul) ]
+ br label %loop.header
+
+loop.header:
+ %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+ %gep.a = getelementptr inbounds i32, ptr %a, i64 %iv
+ %gep.b = getelementptr inbounds i32, ptr %b, i64 %iv
+ %l.b = load i32, ptr %gep.b, align 1
+ %c.1 = icmp sge i32 %l.b, 0
+ br i1 %c.1, label %loop.latch, label %loop.then
+
+loop.then:
+ %l.a = load i32, ptr %gep.a, align 1
+ br label %loop.latch
+
+loop.latch:
+ %merge = phi i32 [ %l.a, %loop.then ], [ %l.b, %loop.header ]
+ %gep.c = getelementptr inbounds i32, ptr %c, i64 %iv
+ store i32 %merge, ptr %gep.c, align 1
+ %iv.next = add nuw nsw i64 %iv, 1
+ %ec = icmp eq i64 %iv.next, %n
+ br i1 %ec, label %exit, label %loop.header
+
+exit:
+ ret void
+}
+
+
+; %a is NOT known dereferenceable via assume for the whole loop.
+define void @deref_assumption_in_preheader_too_small_non_constant_trip_count_access_i32(ptr noalias noundef %a, ptr noalias %b, ptr noalias %c, i64 %n) nofree nosync {
+; CHECK-LABEL: define void @deref_assumption_in_preheader_too_small_non_constant_trip_count_access_i32(
+; CHECK-SAME: ptr noalias noundef [[A:%.*]], ptr noalias [[B:%.*]], ptr noalias [[C:%.*]], i64 [[N:%.*]]) #[[ATTR1]] {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 4), "dereferenceable"(ptr [[A]], i64 [[N]]) ]
+; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 2
+; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK: [[VECTOR_PH]]:
+; CHECK-NEXT: [[N_MOD_VF:%.*]] = urem i64 [[N]], 2
+; CHECK-NEXT: [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
+; CHECK: [[VECTOR_BODY]]:
+; CHECK-NEXT: [[TMP7:%.*]] = getelementptr inbounds i32, ptr [[TMP6]], i32 0
+; CHECK-NEXT: store <2 x i32> [[PREDPHI]], ptr [[TMP7]], align 1
+; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[TMP0]], 2
+; CHECK-NEXT: [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[TMP8]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK: [[MIDDLE_BLOCK]]:
+; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK: [[SCALAR_PH]]:
+; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-NEXT: br label %[[LOOP_HEADER:.*]]
+; CHECK: [[LOOP_HEADER]]:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT: [[GEP_A:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-NEXT: [[GEP_B:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-NEXT: [[L_B:%.*]] = load i32, ptr [[GEP_B]], align 1
+; CHECK-NEXT: [[C_1:%.*]] = icmp sge i32 [[L_B]], 0
+; CHECK-NEXT: br i1 [[C_1]], label %[[LOOP_LATCH]], label %[[LOOP_THEN:.*]]
+; CHECK: [[LOOP_THEN]]:
+; CHECK-NEXT: [[L_A:%.*]] = load i32, ptr [[GEP_A]], align 1
+; CHECK-NEXT: br label %[[LOOP_LATCH]]
+; CHECK: [[LOOP_LATCH]]:
+; CHECK-NEXT: [[MERGE:%.*]] = phi i32 [ [[L_A]], %[[LOOP_THEN]] ], [ [[L_B]], %[[LOOP_HEADER]] ]
+; CHECK-NEXT: [[GEP_C:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[IV]]
+; CHECK-NEXT: store i32 [[MERGE]], ptr [[GEP_C]], align 1
+; CHECK-NEXT: [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-NEXT: [[EC:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-NEXT: br i1 [[EC]], label %[[EXIT]], label %[[LOOP_HEADER]], !llvm.loop [[LOOP7:![0-9]+]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: ret void
+;
+entry:
+ call void @llvm.assume(i1 true) [ "align"(ptr %a, i64 4), "dereferenceable"(ptr %a, i64 %n) ]
+ br label %loop.header
+
+loop.header:
+ %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+ %gep.a = getelementptr inbounds i32, ptr %a, i64 %iv
+ %gep.b = getelementptr inbounds i32, ptr %b, i64 %iv
+ %l.b = load i32, ptr %gep.b, align 1
+ %c.1 = icmp sge i32 %l.b, 0
+ br i1 %c.1, label %loop.latch, label %loop.then
+
+loop.then:
+ %l.a = load i32, ptr %gep.a, align 1
+ br label %loop.latch
+
+loop.latch:
+ %merge = phi i32 [ %l.a, %loop.then ], [ %l.b, %loop.header ]
+ %gep.c = getelementptr inbounds i32, ptr %c, i64 %iv
+ store i32 %merge, ptr %gep.c, align 1
+ %iv.next = add nuw nsw i64 %iv, 1
+ %ec = icmp eq i64 %iv.next, %n
+ br i1 %ec, label %exit, label %loop.header
+
+exit:
+ ret void
+}
+
+; %a is NOT known dereferenceable via assume for the whole loop.
+define void @deref_assumption_in_preheader_too_small2_non_constant_trip_count_access_i32(ptr noalias noundef %a, ptr noalias %b, ptr noalias %c, i64 %n) nofree nosync {
+; CHECK-LABEL: define void @deref_assumption_in_preheader_too_small2_non_constant_trip_count_access_i32(
+; CHECK-SAME: ptr noalias noundef [[A:%.*]], ptr noalias [[B:%.*]], ptr noalias [[C:%.*]], i64 [[N:%.*]]) #[[ATTR1]] {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 4), "dereferenceable"(ptr [[A]], i64 100) ]
+; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 2
+; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK: [[VECTOR_PH]]:
+; CHECK-NEXT: [[N_MOD_VF:%.*]] = urem i64 [[N]], 2
+; CHECK-NEXT: [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
+; CHECK: [[VECTOR_BODY]]:
+; CHECK-NEXT: br i1 [[TMP5]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
+; CHECK: [[PRED_LOAD_IF]]:
+; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE2]]
+; CHECK: [[PRED_LOAD_CONTINUE2]]:
+; CHECK-NEXT: [[WIDE_LOAD1:%.*]] = phi <2 x i32> [ [[TMP9]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP14]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT: [[PREDPHI:%.*]] = select <2 x i1> [[TMP4]], <2 x i32> [[WIDE_LOAD]], <2 x i32> [[WIDE_LOAD1]]
+; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[TMP0]]
+; CHECK-NEXT: [[TMP7:%.*]] = getelementptr inbounds i32, ptr [[TMP6]], i32 0
+; CHECK-NEXT: store <2 x i32> [[PREDPHI]], ptr [[TMP7]], align 1
+; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[TMP0]], 2
+; CHECK-NEXT: [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[TMP8]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
+; CHECK: [[MIDDLE_BLOCK]]:
+; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK: [[SCALAR_PH]]:
+; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-NEXT: br label %[[LOOP_HEADER:.*]]
+; CHECK: [[LOOP_HEADER]]:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT: [[GEP_A:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-NEXT: [[GEP_B:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-NEXT: [[L_B:%.*]] = load i32, ptr [[GEP_B]], align 1
+; CHECK-NEXT: [[C_1:%.*]] = icmp sge i32 [[L_B]], 0
+; CHECK-NEXT: br i1 [[C_1]], label %[[LOOP_LATCH]], label %[[LOOP_THEN:.*]]
+; CHECK: [[LOOP_THEN]]:
+; CHECK-NEXT: [[L_A:%.*]] = load i32, ptr [[GEP_A]], align 1
+; CHECK-NEXT: br label %[[LOOP_LATCH]]
+; CHECK: [[LOOP_LATCH]]:
+; CHECK-NEXT: [[MERGE:%.*]] = phi i32 [ [[L_A]], %[[LOOP_THEN]] ], [ [[L_B]], %[[LOOP_HEADER]] ]
+; CHECK-NEXT: [[GEP_C:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[IV]]
+; CHECK-NEXT: store i32 [[MERGE]], ptr [[GEP_C]], align 1
+; CHECK-NEXT: [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-NEXT: [[EC:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-NEXT: br i1 [[EC]], label %[[EXIT]], label %[[LOOP_HEADER]], !llvm.loop [[LOOP9:![0-9]+]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: ret void
+;
+entry:
+ call void @llvm.assume(i1 true) [ "align"(ptr %a, i64 4), "dereferenceable"(ptr %a, i64 100) ]
+ br label %loop.header
+
+loop.header:
+ %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+ %gep.a = getelementptr inbounds i32, ptr %a, i64 %iv
+ %gep.b = getelementptr inbounds i32, ptr %b, i64 %iv
+ %l.b = load i32, ptr %gep.b, align 1
+ %c.1 = icmp sge i32 %l.b, 0
+ br i1 %c.1, label %loop.latch, label %loop.then
+
+loop.then:
+ %l.a = load i32, ptr %gep.a, align 1
+ br label %loop.latch
+
+loop.latch:
+ %merge = phi i32 [ %l.a, %loop.then ], [ %l.b, %loop.header ]
+ %gep.c = getelementptr inbounds i32, ptr %c, i64 %iv
+ store i32 %merge, ptr %gep.c, align 1
+ %iv.next = add nuw nsw i64 %iv, 1
+ %ec = icmp eq i64 %iv.next, %n
+ br i1 %ec, label %exit, label %loop.header
+
+exit:
+ ret void
+}
>From 3fc3d703d6356d012fb07c3728b748a9b79b16c1 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Mon, 24 Feb 2025 11:25:11 +0000
Subject: [PATCH 2/6] !fixup remove left over code.
---
llvm/lib/Analysis/Loads.cpp | 35 +++++------------------------------
1 file changed, 5 insertions(+), 30 deletions(-)
diff --git a/llvm/lib/Analysis/Loads.cpp b/llvm/lib/Analysis/Loads.cpp
index 73fe2e91ab877..b389bf8f5aa72 100644
--- a/llvm/lib/Analysis/Loads.cpp
+++ b/llvm/lib/Analysis/Loads.cpp
@@ -36,6 +36,11 @@ static bool isDereferenceableAndAlignedPointerViaAssumption(
function_ref<bool(const RetainedKnowledge &RK)> CheckSize,
const DataLayout &DL, const Instruction *CtxI, AssumptionCache *AC,
const DominatorTree *DT) {
+ // Dereferenceable information from assumptions is only valid if the value
+ // cannot be freed between the assumption and use. For now just use the
+ // information for values that cannot be freed in the function.
+ // TODO: More precisely check if the pointer can be freed between assumption
+ // and use.
if (!CtxI || Ptr->canBeFreed())
return false;
/// Look through assumes to see if both dereferencability and alignment can
@@ -198,36 +203,6 @@ static bool isDereferenceableAndAlignedPointer(
Size, DL, CtxI, AC, DT, TLI,
Visited, MaxDepth);
- // Dereferenceable information from assumptions is only valid if the value
- // cannot be freed between the assumption and use. For now just use the
- // information for values that cannot be freed in the function.
- // TODO: More precisely check if the pointer can be freed between assumption
- // and use.
- if (CtxI && AC && !V->canBeFreed()) {
- /// Look through assumes to see if both dereferencability and alignment can
- /// be proven by an assume if needed.
- RetainedKnowledge AlignRK;
- RetainedKnowledge DerefRK;
- bool IsAligned = V->getPointerAlignment(DL) >= Alignment;
- if (getKnowledgeForValue(
- V, {Attribute::Dereferenceable, Attribute::Alignment}, *AC,
- [&](RetainedKnowledge RK, Instruction *Assume, auto) {
- if (!isValidAssumeForContext(Assume, CtxI, DT))
- return false;
- if (RK.AttrKind == Attribute::Alignment)
- AlignRK = std::max(AlignRK, RK);
- if (RK.AttrKind == Attribute::Dereferenceable)
- DerefRK = std::max(DerefRK, RK);
- IsAligned |= AlignRK && AlignRK.ArgValue >= Alignment.value();
- if (IsAligned && DerefRK &&
- DerefRK.ArgValue >= Size.getZExtValue())
- return true; // We have found what we needed so we stop looking
- return false; // Other assumes may have better information. so
- // keep looking
- }))
- return true;
- }
-
return isDereferenceableAndAlignedPointerViaAssumption(
V, Alignment,
[Size](const RetainedKnowledge &RK) {
>From a56508982fdb52a71ea7b7d8a3cd7f90128c8c2a Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Mon, 24 Feb 2025 21:24:26 +0000
Subject: [PATCH 3/6] !fixup use AccessSizeSCEV.
---
llvm/lib/Analysis/Loads.cpp | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/llvm/lib/Analysis/Loads.cpp b/llvm/lib/Analysis/Loads.cpp
index b389bf8f5aa72..592a9667bc129 100644
--- a/llvm/lib/Analysis/Loads.cpp
+++ b/llvm/lib/Analysis/Loads.cpp
@@ -383,8 +383,8 @@ bool llvm::isDereferenceableAndAlignedInLoop(
Instruction *HeaderFirstNonPHI = &*L->getHeader()->getFirstNonPHIIt();
return isDereferenceableAndAlignedPointerViaAssumption(
Base, Alignment,
- [&SE, PtrDiff](const RetainedKnowledge &RK) {
- return SE.isKnownPredicate(CmpInst::ICMP_ULE, PtrDiff,
+ [&SE, AccessSizeSCEV](const RetainedKnowledge &RK) {
+ return SE.isKnownPredicate(CmpInst::ICMP_ULE, AccessSizeSCEV,
SE.getSCEV(RK.IRArgValue));
},
DL, HeaderFirstNonPHI, AC, &DT) ||
>From b180cd708a3bb28f383e63c1291e70e892cae520 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Mon, 23 Jun 2025 20:36:08 +0100
Subject: [PATCH 4/6] !fixup after rebase
---
.../llvm/Analysis/AssumeBundleQueries.h | 5 +-
llvm/lib/Analysis/AssumeBundleQueries.cpp | 4 +-
llvm/lib/Analysis/Loads.cpp | 14 +--
...able-info-from-assumption-variable-size.ll | 101 ++++++++++--------
4 files changed, 71 insertions(+), 53 deletions(-)
diff --git a/llvm/include/llvm/Analysis/AssumeBundleQueries.h b/llvm/include/llvm/Analysis/AssumeBundleQueries.h
index 752eb25038c7d..eb537e5f11afc 100644
--- a/llvm/include/llvm/Analysis/AssumeBundleQueries.h
+++ b/llvm/include/llvm/Analysis/AssumeBundleQueries.h
@@ -104,9 +104,12 @@ struct RetainedKnowledge {
uint64_t ArgValue = 0;
Value *IRArgValue = nullptr;
Value *WasOn = nullptr;
+ RetainedKnowledge(Attribute::AttrKind AttrKind = Attribute::None,
+ uint64_t ArgValue = 0, Value *WasOn = nullptr)
+ : AttrKind(AttrKind), ArgValue(ArgValue), WasOn(WasOn) {}
bool operator==(RetainedKnowledge Other) const {
return AttrKind == Other.AttrKind && WasOn == Other.WasOn &&
- ArgValue == Other.ArgValue;
+ ArgValue == Other.ArgValue && IRArgValue == Other.IRArgValue;
}
bool operator!=(RetainedKnowledge Other) const { return !(*this == Other); }
/// This is only intended for use in std::min/std::max between attribute that
diff --git a/llvm/lib/Analysis/AssumeBundleQueries.cpp b/llvm/lib/Analysis/AssumeBundleQueries.cpp
index d1548c7db5bcd..aa1cb3c26d63f 100644
--- a/llvm/lib/Analysis/AssumeBundleQueries.cpp
+++ b/llvm/lib/Analysis/AssumeBundleQueries.cpp
@@ -114,7 +114,9 @@ llvm::getKnowledgeFromBundle(AssumeInst &Assume,
};
if (BOI.End - BOI.Begin > ABA_Argument)
Result.ArgValue = GetArgOr1(0);
- Result.IRArgValue = getValueFromBundleOpInfo(Assume, BOI, ABA_Argument);
+ Result.IRArgValue = bundleHasArgument(BOI, ABA_Argument)
+ ? getValueFromBundleOpInfo(Assume, BOI, ABA_Argument)
+ : nullptr;
if (Result.AttrKind == Attribute::Alignment)
if (BOI.End - BOI.Begin > ABA_Argument + 1)
Result.ArgValue = MinAlign(Result.ArgValue, GetArgOr1(1));
diff --git a/llvm/lib/Analysis/Loads.cpp b/llvm/lib/Analysis/Loads.cpp
index 592a9667bc129..89e42ff4e8029 100644
--- a/llvm/lib/Analysis/Loads.cpp
+++ b/llvm/lib/Analysis/Loads.cpp
@@ -49,7 +49,7 @@ static bool isDereferenceableAndAlignedPointerViaAssumption(
RetainedKnowledge DerefRK;
bool IsAligned = Ptr->getPointerAlignment(DL) >= Alignment;
return getKnowledgeForValue(
- Ptr, {Attribute::Dereferenceable, Attribute::Alignment}, AC,
+ Ptr, {Attribute::Dereferenceable, Attribute::Alignment}, *AC,
[&](RetainedKnowledge RK, Instruction *Assume, auto) {
if (!isValidAssumeForContext(Assume, CtxI, DT))
return false;
@@ -203,12 +203,12 @@ static bool isDereferenceableAndAlignedPointer(
Size, DL, CtxI, AC, DT, TLI,
Visited, MaxDepth);
- return isDereferenceableAndAlignedPointerViaAssumption(
- V, Alignment,
- [Size](const RetainedKnowledge &RK) {
- return RK.ArgValue >= Size.getZExtValue();
- },
- DL, CtxI, AC, DT);
+ return AC && isDereferenceableAndAlignedPointerViaAssumption(
+ V, Alignment,
+ [Size](const RetainedKnowledge &RK) {
+ return RK.ArgValue >= Size.getZExtValue();
+ },
+ DL, CtxI, AC, DT);
}
bool llvm::isDereferenceableAndAlignedPointer(
diff --git a/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-variable-size.ll b/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-variable-size.ll
index d40fc53cf2d4e..da69e13dd91d6 100644
--- a/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-variable-size.ll
+++ b/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-variable-size.ll
@@ -16,32 +16,14 @@ define void @deref_assumption_in_preheader_non_constant_trip_count_access_i8(ptr
; CHECK-NEXT: [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
; CHECK: [[VECTOR_BODY]]:
-; CHECK-NEXT: [[TMP0:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_LOAD_CONTINUE2:.*]] ]
+; CHECK-NEXT: [[TMP0:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT: [[TMP1:%.*]] = getelementptr i8, ptr [[A]], i64 [[TMP0]]
; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[B]], i64 [[TMP0]]
; CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[TMP2]], i32 0
; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <2 x i8>, ptr [[TMP3]], align 1
; CHECK-NEXT: [[TMP4:%.*]] = icmp sge <2 x i8> [[WIDE_LOAD]], zeroinitializer
-; CHECK-NEXT: [[TMP15:%.*]] = xor <2 x i1> [[TMP4]], splat (i1 true)
-; CHECK-NEXT: [[TMP5:%.*]] = extractelement <2 x i1> [[TMP15]], i32 0
-; CHECK-NEXT: br i1 [[TMP5]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
-; CHECK: [[PRED_LOAD_IF]]:
-; CHECK-NEXT: [[TMP19:%.*]] = add i64 [[TMP0]], 0
-; CHECK-NEXT: [[TMP16:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 [[TMP19]]
-; CHECK-NEXT: [[TMP17:%.*]] = load i8, ptr [[TMP16]], align 1
-; CHECK-NEXT: [[TMP18:%.*]] = insertelement <2 x i8> poison, i8 [[TMP17]], i32 0
-; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE]]
-; CHECK: [[PRED_LOAD_CONTINUE]]:
-; CHECK-NEXT: [[TMP9:%.*]] = phi <2 x i8> [ poison, %[[VECTOR_BODY]] ], [ [[TMP18]], %[[PRED_LOAD_IF]] ]
-; CHECK-NEXT: [[TMP10:%.*]] = extractelement <2 x i1> [[TMP15]], i32 1
-; CHECK-NEXT: br i1 [[TMP10]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2]]
-; CHECK: [[PRED_LOAD_IF1]]:
-; CHECK-NEXT: [[TMP11:%.*]] = add i64 [[TMP0]], 1
-; CHECK-NEXT: [[TMP12:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 [[TMP11]]
-; CHECK-NEXT: [[TMP13:%.*]] = load i8, ptr [[TMP12]], align 1
-; CHECK-NEXT: [[TMP14:%.*]] = insertelement <2 x i8> [[TMP9]], i8 [[TMP13]], i32 1
-; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE2]]
-; CHECK: [[PRED_LOAD_CONTINUE2]]:
-; CHECK-NEXT: [[WIDE_LOAD1:%.*]] = phi <2 x i8> [ [[TMP9]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP14]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT: [[TMP5:%.*]] = getelementptr i8, ptr [[TMP1]], i32 0
+; CHECK-NEXT: [[WIDE_LOAD1:%.*]] = load <2 x i8>, ptr [[TMP5]], align 1
; CHECK-NEXT: [[PREDPHI:%.*]] = select <2 x i1> [[TMP4]], <2 x i8> [[WIDE_LOAD]], <2 x i8> [[WIDE_LOAD1]]
; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i8, ptr [[C]], i64 [[TMP0]]
; CHECK-NEXT: [[TMP7:%.*]] = getelementptr inbounds i8, ptr [[TMP6]], i32 0
@@ -117,32 +99,14 @@ define void @deref_assumption_in_preheader_non_constant_trip_count_access_i32(pt
; CHECK-NEXT: [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
; CHECK: [[VECTOR_BODY]]:
-; CHECK-NEXT: [[TMP0:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_LOAD_CONTINUE2:.*]] ]
+; CHECK-NEXT: [[TMP0:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT: [[TMP1:%.*]] = getelementptr i32, ptr [[A]], i64 [[TMP0]]
; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[TMP0]]
; CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[TMP2]], i32 0
; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <2 x i32>, ptr [[TMP3]], align 1
; CHECK-NEXT: [[TMP4:%.*]] = icmp sge <2 x i32> [[WIDE_LOAD]], zeroinitializer
-; CHECK-NEXT: [[TMP15:%.*]] = xor <2 x i1> [[TMP4]], splat (i1 true)
-; CHECK-NEXT: [[TMP5:%.*]] = extractelement <2 x i1> [[TMP15]], i32 0
-; CHECK-NEXT: br i1 [[TMP5]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
-; CHECK: [[PRED_LOAD_IF]]:
-; CHECK-NEXT: [[TMP19:%.*]] = add i64 [[TMP0]], 0
-; CHECK-NEXT: [[TMP16:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP19]]
-; CHECK-NEXT: [[TMP17:%.*]] = load i32, ptr [[TMP16]], align 1
-; CHECK-NEXT: [[TMP18:%.*]] = insertelement <2 x i32> poison, i32 [[TMP17]], i32 0
-; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE]]
-; CHECK: [[PRED_LOAD_CONTINUE]]:
-; CHECK-NEXT: [[TMP9:%.*]] = phi <2 x i32> [ poison, %[[VECTOR_BODY]] ], [ [[TMP18]], %[[PRED_LOAD_IF]] ]
-; CHECK-NEXT: [[TMP10:%.*]] = extractelement <2 x i1> [[TMP15]], i32 1
-; CHECK-NEXT: br i1 [[TMP10]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2]]
-; CHECK: [[PRED_LOAD_IF1]]:
-; CHECK-NEXT: [[TMP11:%.*]] = add i64 [[TMP0]], 1
-; CHECK-NEXT: [[TMP12:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP11]]
-; CHECK-NEXT: [[TMP13:%.*]] = load i32, ptr [[TMP12]], align 1
-; CHECK-NEXT: [[TMP14:%.*]] = insertelement <2 x i32> [[TMP9]], i32 [[TMP13]], i32 1
-; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE2]]
-; CHECK: [[PRED_LOAD_CONTINUE2]]:
-; CHECK-NEXT: [[WIDE_LOAD1:%.*]] = phi <2 x i32> [ [[TMP9]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP14]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT: [[TMP5:%.*]] = getelementptr i32, ptr [[TMP1]], i32 0
+; CHECK-NEXT: [[WIDE_LOAD1:%.*]] = load <2 x i32>, ptr [[TMP5]], align 1
; CHECK-NEXT: [[PREDPHI:%.*]] = select <2 x i1> [[TMP4]], <2 x i32> [[WIDE_LOAD]], <2 x i32> [[WIDE_LOAD1]]
; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[TMP0]]
; CHECK-NEXT: [[TMP7:%.*]] = getelementptr inbounds i32, ptr [[TMP6]], i32 0
@@ -219,6 +183,34 @@ define void @deref_assumption_in_preheader_too_small_non_constant_trip_count_acc
; CHECK-NEXT: [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
; CHECK: [[VECTOR_BODY]]:
+; CHECK-NEXT: [[TMP0:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_LOAD_CONTINUE2:.*]] ]
+; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[TMP0]]
+; CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[TMP2]], i32 0
+; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <2 x i32>, ptr [[TMP3]], align 1
+; CHECK-NEXT: [[TMP4:%.*]] = icmp sge <2 x i32> [[WIDE_LOAD]], zeroinitializer
+; CHECK-NEXT: [[TMP15:%.*]] = xor <2 x i1> [[TMP4]], splat (i1 true)
+; CHECK-NEXT: [[TMP5:%.*]] = extractelement <2 x i1> [[TMP15]], i32 0
+; CHECK-NEXT: br i1 [[TMP5]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
+; CHECK: [[PRED_LOAD_IF]]:
+; CHECK-NEXT: [[TMP19:%.*]] = add i64 [[TMP0]], 0
+; CHECK-NEXT: [[TMP16:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP19]]
+; CHECK-NEXT: [[TMP17:%.*]] = load i32, ptr [[TMP16]], align 1
+; CHECK-NEXT: [[TMP18:%.*]] = insertelement <2 x i32> poison, i32 [[TMP17]], i32 0
+; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE]]
+; CHECK: [[PRED_LOAD_CONTINUE]]:
+; CHECK-NEXT: [[TMP9:%.*]] = phi <2 x i32> [ poison, %[[VECTOR_BODY]] ], [ [[TMP18]], %[[PRED_LOAD_IF]] ]
+; CHECK-NEXT: [[TMP10:%.*]] = extractelement <2 x i1> [[TMP15]], i32 1
+; CHECK-NEXT: br i1 [[TMP10]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2]]
+; CHECK: [[PRED_LOAD_IF1]]:
+; CHECK-NEXT: [[TMP11:%.*]] = add i64 [[TMP0]], 1
+; CHECK-NEXT: [[TMP12:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP11]]
+; CHECK-NEXT: [[TMP13:%.*]] = load i32, ptr [[TMP12]], align 1
+; CHECK-NEXT: [[TMP14:%.*]] = insertelement <2 x i32> [[TMP9]], i32 [[TMP13]], i32 1
+; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE2]]
+; CHECK: [[PRED_LOAD_CONTINUE2]]:
+; CHECK-NEXT: [[WIDE_LOAD1:%.*]] = phi <2 x i32> [ [[TMP9]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP14]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT: [[PREDPHI:%.*]] = select <2 x i1> [[TMP4]], <2 x i32> [[WIDE_LOAD]], <2 x i32> [[WIDE_LOAD1]]
+; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[TMP0]]
; CHECK-NEXT: [[TMP7:%.*]] = getelementptr inbounds i32, ptr [[TMP6]], i32 0
; CHECK-NEXT: store <2 x i32> [[PREDPHI]], ptr [[TMP7]], align 1
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[TMP0]], 2
@@ -291,8 +283,29 @@ define void @deref_assumption_in_preheader_too_small2_non_constant_trip_count_ac
; CHECK-NEXT: [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
; CHECK: [[VECTOR_BODY]]:
+; CHECK-NEXT: [[TMP0:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_LOAD_CONTINUE2:.*]] ]
+; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[TMP0]]
+; CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[TMP2]], i32 0
+; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <2 x i32>, ptr [[TMP3]], align 1
+; CHECK-NEXT: [[TMP4:%.*]] = icmp sge <2 x i32> [[WIDE_LOAD]], zeroinitializer
+; CHECK-NEXT: [[TMP15:%.*]] = xor <2 x i1> [[TMP4]], splat (i1 true)
+; CHECK-NEXT: [[TMP5:%.*]] = extractelement <2 x i1> [[TMP15]], i32 0
; CHECK-NEXT: br i1 [[TMP5]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
; CHECK: [[PRED_LOAD_IF]]:
+; CHECK-NEXT: [[TMP19:%.*]] = add i64 [[TMP0]], 0
+; CHECK-NEXT: [[TMP16:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP19]]
+; CHECK-NEXT: [[TMP17:%.*]] = load i32, ptr [[TMP16]], align 1
+; CHECK-NEXT: [[TMP18:%.*]] = insertelement <2 x i32> poison, i32 [[TMP17]], i32 0
+; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE]]
+; CHECK: [[PRED_LOAD_CONTINUE]]:
+; CHECK-NEXT: [[TMP9:%.*]] = phi <2 x i32> [ poison, %[[VECTOR_BODY]] ], [ [[TMP18]], %[[PRED_LOAD_IF]] ]
+; CHECK-NEXT: [[TMP10:%.*]] = extractelement <2 x i1> [[TMP15]], i32 1
+; CHECK-NEXT: br i1 [[TMP10]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2]]
+; CHECK: [[PRED_LOAD_IF1]]:
+; CHECK-NEXT: [[TMP11:%.*]] = add i64 [[TMP0]], 1
+; CHECK-NEXT: [[TMP12:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP11]]
+; CHECK-NEXT: [[TMP13:%.*]] = load i32, ptr [[TMP12]], align 1
+; CHECK-NEXT: [[TMP14:%.*]] = insertelement <2 x i32> [[TMP9]], i32 [[TMP13]], i32 1
; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE2]]
; CHECK: [[PRED_LOAD_CONTINUE2]]:
; CHECK-NEXT: [[WIDE_LOAD1:%.*]] = phi <2 x i32> [ [[TMP9]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP14]], %[[PRED_LOAD_IF1]] ]
>From 02483483a49382e5c4796f1ecc0d54fadfe2daa5 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Tue, 24 Jun 2025 21:16:11 +0100
Subject: [PATCH 5/6] !fixup add test with align attribute
---
...able-info-from-assumption-variable-size.ll | 186 ++++++++++++++++++
1 file changed, 186 insertions(+)
diff --git a/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-variable-size.ll b/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-variable-size.ll
index da69e13dd91d6..e771c408358a1 100644
--- a/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-variable-size.ll
+++ b/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-variable-size.ll
@@ -369,3 +369,189 @@ loop.latch:
exit:
ret void
}
+
+; %a is known dereferenceable via assume for the whole loop, alignment is known via function attribute.
+define void @deref_assumption_in_preheader_non_constant_trip_count_access_i32_align_attribute(ptr noalias noundef align 4 %a, ptr noalias %b, ptr noalias %c, i64 %n) nofree nosync {
+; CHECK-LABEL: define void @deref_assumption_in_preheader_non_constant_trip_count_access_i32_align_attribute(
+; CHECK-SAME: ptr noalias noundef align 4 [[A:%.*]], ptr noalias [[B:%.*]], ptr noalias [[C:%.*]], i64 [[N:%.*]]) #[[ATTR1]] {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: [[MUL:%.*]] = mul nuw nsw i64 [[N]], 4
+; CHECK-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[A]], i64 [[MUL]]) ]
+; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 2
+; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK: [[VECTOR_PH]]:
+; CHECK-NEXT: [[N_MOD_VF:%.*]] = urem i64 [[N]], 2
+; CHECK-NEXT: [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
+; CHECK: [[VECTOR_BODY]]:
+; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT: [[TMP0:%.*]] = getelementptr i32, ptr [[A]], i64 [[INDEX]]
+; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[INDEX]]
+; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i32 0
+; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <2 x i32>, ptr [[TMP2]], align 4
+; CHECK-NEXT: [[TMP3:%.*]] = icmp sge <2 x i32> [[WIDE_LOAD]], zeroinitializer
+; CHECK-NEXT: [[TMP4:%.*]] = getelementptr i32, ptr [[TMP0]], i32 0
+; CHECK-NEXT: [[WIDE_LOAD1:%.*]] = load <2 x i32>, ptr [[TMP4]], align 4
+; CHECK-NEXT: [[PREDPHI:%.*]] = select <2 x i1> [[TMP3]], <2 x i32> [[WIDE_LOAD]], <2 x i32> [[WIDE_LOAD1]]
+; CHECK-NEXT: [[TMP5:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[INDEX]]
+; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i32, ptr [[TMP5]], i32 0
+; CHECK-NEXT: store <2 x i32> [[PREDPHI]], ptr [[TMP6]], align 1
+; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
+; CHECK-NEXT: [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[TMP7]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP10:![0-9]+]]
+; CHECK: [[MIDDLE_BLOCK]]:
+; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK: [[SCALAR_PH]]:
+; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-NEXT: br label %[[LOOP_HEADER:.*]]
+; CHECK: [[LOOP_HEADER]]:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT: [[GEP_A:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-NEXT: [[GEP_B:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-NEXT: [[L_B:%.*]] = load i32, ptr [[GEP_B]], align 4
+; CHECK-NEXT: [[C_1:%.*]] = icmp sge i32 [[L_B]], 0
+; CHECK-NEXT: br i1 [[C_1]], label %[[LOOP_LATCH]], label %[[LOOP_THEN:.*]]
+; CHECK: [[LOOP_THEN]]:
+; CHECK-NEXT: [[L_A:%.*]] = load i32, ptr [[GEP_A]], align 4
+; CHECK-NEXT: br label %[[LOOP_LATCH]]
+; CHECK: [[LOOP_LATCH]]:
+; CHECK-NEXT: [[MERGE:%.*]] = phi i32 [ [[L_A]], %[[LOOP_THEN]] ], [ [[L_B]], %[[LOOP_HEADER]] ]
+; CHECK-NEXT: [[GEP_C:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[IV]]
+; CHECK-NEXT: store i32 [[MERGE]], ptr [[GEP_C]], align 1
+; CHECK-NEXT: [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-NEXT: [[EC:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-NEXT: br i1 [[EC]], label %[[EXIT]], label %[[LOOP_HEADER]], !llvm.loop [[LOOP11:![0-9]+]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: ret void
+;
+entry:
+ %mul = mul nsw nuw i64 %n, 4
+ call void @llvm.assume(i1 true) [ "dereferenceable"(ptr %a, i64 %mul) ]
+ br label %loop.header
+
+loop.header:
+ %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+ %gep.a = getelementptr inbounds i32, ptr %a, i64 %iv
+ %gep.b = getelementptr inbounds i32, ptr %b, i64 %iv
+ %l.b = load i32, ptr %gep.b, align 4
+ %c.1 = icmp sge i32 %l.b, 0
+ br i1 %c.1, label %loop.latch, label %loop.then
+
+loop.then:
+ %l.a = load i32, ptr %gep.a, align 4
+ br label %loop.latch
+
+loop.latch:
+ %merge = phi i32 [ %l.a, %loop.then ], [ %l.b, %loop.header ]
+ %gep.c = getelementptr inbounds i32, ptr %c, i64 %iv
+ store i32 %merge, ptr %gep.c, align 1
+ %iv.next = add nuw nsw i64 %iv, 1
+ %ec = icmp eq i64 %iv.next, %n
+ br i1 %ec, label %exit, label %loop.header
+
+exit:
+ ret void
+}
+
+; Alignment via argument attribute is too small (1 but needs 4).
+define void @deref_assumption_in_preheader_non_constant_trip_count_access_i32_align_attribute_too_small(ptr noalias noundef align 1 %a, ptr noalias %b, ptr noalias %c, i64 %n) nofree nosync {
+; CHECK-LABEL: define void @deref_assumption_in_preheader_non_constant_trip_count_access_i32_align_attribute_too_small(
+; CHECK-SAME: ptr noalias noundef align 1 [[A:%.*]], ptr noalias [[B:%.*]], ptr noalias [[C:%.*]], i64 [[N:%.*]]) #[[ATTR1]] {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: [[MUL:%.*]] = mul nuw nsw i64 [[N]], 4
+; CHECK-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[A]], i64 [[MUL]]) ]
+; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 2
+; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK: [[VECTOR_PH]]:
+; CHECK-NEXT: [[N_MOD_VF:%.*]] = urem i64 [[N]], 2
+; CHECK-NEXT: [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
+; CHECK: [[VECTOR_BODY]]:
+; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_LOAD_CONTINUE2:.*]] ]
+; CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[INDEX]]
+; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[TMP0]], i32 0
+; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <2 x i32>, ptr [[TMP1]], align 4
+; CHECK-NEXT: [[TMP2:%.*]] = icmp sge <2 x i32> [[WIDE_LOAD]], zeroinitializer
+; CHECK-NEXT: [[TMP3:%.*]] = xor <2 x i1> [[TMP2]], splat (i1 true)
+; CHECK-NEXT: [[TMP4:%.*]] = extractelement <2 x i1> [[TMP3]], i32 0
+; CHECK-NEXT: br i1 [[TMP4]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
+; CHECK: [[PRED_LOAD_IF]]:
+; CHECK-NEXT: [[TMP5:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP5]]
+; CHECK-NEXT: [[TMP7:%.*]] = load i32, ptr [[TMP6]], align 4
+; CHECK-NEXT: [[TMP8:%.*]] = insertelement <2 x i32> poison, i32 [[TMP7]], i32 0
+; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE]]
+; CHECK: [[PRED_LOAD_CONTINUE]]:
+; CHECK-NEXT: [[TMP9:%.*]] = phi <2 x i32> [ poison, %[[VECTOR_BODY]] ], [ [[TMP8]], %[[PRED_LOAD_IF]] ]
+; CHECK-NEXT: [[TMP10:%.*]] = extractelement <2 x i1> [[TMP3]], i32 1
+; CHECK-NEXT: br i1 [[TMP10]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2]]
+; CHECK: [[PRED_LOAD_IF1]]:
+; CHECK-NEXT: [[TMP11:%.*]] = add i64 [[INDEX]], 1
+; CHECK-NEXT: [[TMP12:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP11]]
+; CHECK-NEXT: [[TMP13:%.*]] = load i32, ptr [[TMP12]], align 4
+; CHECK-NEXT: [[TMP14:%.*]] = insertelement <2 x i32> [[TMP9]], i32 [[TMP13]], i32 1
+; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE2]]
+; CHECK: [[PRED_LOAD_CONTINUE2]]:
+; CHECK-NEXT: [[TMP15:%.*]] = phi <2 x i32> [ [[TMP9]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP14]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT: [[PREDPHI:%.*]] = select <2 x i1> [[TMP2]], <2 x i32> [[WIDE_LOAD]], <2 x i32> [[TMP15]]
+; CHECK-NEXT: [[TMP16:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[INDEX]]
+; CHECK-NEXT: [[TMP17:%.*]] = getelementptr inbounds i32, ptr [[TMP16]], i32 0
+; CHECK-NEXT: store <2 x i32> [[PREDPHI]], ptr [[TMP17]], align 1
+; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
+; CHECK-NEXT: [[TMP18:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[TMP18]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP12:![0-9]+]]
+; CHECK: [[MIDDLE_BLOCK]]:
+; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK: [[SCALAR_PH]]:
+; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-NEXT: br label %[[LOOP_HEADER:.*]]
+; CHECK: [[LOOP_HEADER]]:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT: [[GEP_A:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-NEXT: [[GEP_B:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-NEXT: [[L_B:%.*]] = load i32, ptr [[GEP_B]], align 4
+; CHECK-NEXT: [[C_1:%.*]] = icmp sge i32 [[L_B]], 0
+; CHECK-NEXT: br i1 [[C_1]], label %[[LOOP_LATCH]], label %[[LOOP_THEN:.*]]
+; CHECK: [[LOOP_THEN]]:
+; CHECK-NEXT: [[L_A:%.*]] = load i32, ptr [[GEP_A]], align 4
+; CHECK-NEXT: br label %[[LOOP_LATCH]]
+; CHECK: [[LOOP_LATCH]]:
+; CHECK-NEXT: [[MERGE:%.*]] = phi i32 [ [[L_A]], %[[LOOP_THEN]] ], [ [[L_B]], %[[LOOP_HEADER]] ]
+; CHECK-NEXT: [[GEP_C:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[IV]]
+; CHECK-NEXT: store i32 [[MERGE]], ptr [[GEP_C]], align 1
+; CHECK-NEXT: [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-NEXT: [[EC:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-NEXT: br i1 [[EC]], label %[[EXIT]], label %[[LOOP_HEADER]], !llvm.loop [[LOOP13:![0-9]+]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: ret void
+;
+entry:
+ %mul = mul nsw nuw i64 %n, 4
+ call void @llvm.assume(i1 true) [ "dereferenceable"(ptr %a, i64 %mul) ]
+ br label %loop.header
+
+loop.header:
+ %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+ %gep.a = getelementptr inbounds i32, ptr %a, i64 %iv
+ %gep.b = getelementptr inbounds i32, ptr %b, i64 %iv
+ %l.b = load i32, ptr %gep.b, align 4
+ %c.1 = icmp sge i32 %l.b, 0
+ br i1 %c.1, label %loop.latch, label %loop.then
+
+loop.then:
+ %l.a = load i32, ptr %gep.a, align 4
+ br label %loop.latch
+
+loop.latch:
+ %merge = phi i32 [ %l.a, %loop.then ], [ %l.b, %loop.header ]
+ %gep.c = getelementptr inbounds i32, ptr %c, i64 %iv
+ store i32 %merge, ptr %gep.c, align 1
+ %iv.next = add nuw nsw i64 %iv, 1
+ %ec = icmp eq i64 %iv.next, %n
+ br i1 %ec, label %exit, label %loop.header
+
+exit:
+ ret void
+}
>From 66c0ed030486a1ced3c4e1c728b8ec79dc97df6f Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Tue, 24 Jun 2025 22:09:45 +0100
Subject: [PATCH 6/6] !fixup allow non-constant integer.
---
llvm/lib/IR/Verifier.cpp | 9 ++++++
.../early_exit_store_legality.ll | 29 +++++++++++++++++++
llvm/test/Verifier/assume-bundles.ll | 10 +++----
3 files changed, 43 insertions(+), 5 deletions(-)
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 227afe2b7b61b..a431832faca60 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -5604,6 +5604,15 @@ void Verifier::visitIntrinsicCall(Intrinsic::ID ID, CallBase &Call) {
"third argument should be an integer if present", Call);
continue;
}
+ if (Kind == Attribute::Dereferenceable) {
+ Check(ArgCount == 2,
+ "dereferenceable assumptions should have 2 arguments", Call);
+ Check(Call.getOperand(Elem.Begin)->getType()->isPointerTy(),
+ "first argument should be a pointer", Call);
+ Check(Call.getOperand(Elem.Begin + 1)->getType()->isIntegerTy(),
+ "second argument should be an integer", Call);
+ continue;
+ }
Check(ArgCount <= 2, "too many arguments", Call);
if (Kind == Attribute::None)
break;
diff --git a/llvm/test/Transforms/LoopVectorize/early_exit_store_legality.ll b/llvm/test/Transforms/LoopVectorize/early_exit_store_legality.ll
index 13fd2eff87290..84d5ceeb601b6 100644
--- a/llvm/test/Transforms/LoopVectorize/early_exit_store_legality.ll
+++ b/llvm/test/Transforms/LoopVectorize/early_exit_store_legality.ll
@@ -165,6 +165,35 @@ exit:
ret void
}
+define void @loop_contains_store_assumed_bounds(ptr noalias %array, ptr readonly %pred, i32 %n) {
+; CHECK-LABEL: LV: Checking a loop in 'loop_contains_store_assumed_bounds'
+; CHECK: LV: Not vectorizing: Writes to memory unsupported in early exit loops.
+entry:
+ %n_bytes = mul nuw nsw i32 %n, 2
+ call void @llvm.assume(i1 true) [ "align"(ptr %pred, i64 2), "dereferenceable"(ptr %pred, i32 %n_bytes) ]
+ %tc = sext i32 %n to i64
+ br label %for.body
+
+for.body:
+ %iv = phi i64 [ 0, %entry ], [ %iv.next, %for.inc ]
+ %st.addr = getelementptr inbounds nuw i16, ptr %array, i64 %iv
+ %data = load i16, ptr %st.addr, align 2
+ %inc = add nsw i16 %data, 1
+ store i16 %inc, ptr %st.addr, align 2
+ %ee.addr = getelementptr inbounds nuw i16, ptr %pred, i64 %iv
+ %ee.val = load i16, ptr %ee.addr, align 2
+ %ee.cond = icmp sgt i16 %ee.val, 500
+ br i1 %ee.cond, label %exit, label %for.inc
+
+for.inc:
+ %iv.next = add nuw nsw i64 %iv, 1
+ %counted.cond = icmp eq i64 %iv.next, %tc
+ br i1 %counted.cond, label %exit, label %for.body
+
+exit:
+ ret void
+}
+
define void @loop_contains_store_to_pointer_with_no_deref_info(ptr align 2 dereferenceable(40) readonly %load.array, ptr align 2 noalias %array, ptr align 2 dereferenceable(40) readonly %pred) {
; CHECK-LABEL: LV: Checking a loop in 'loop_contains_store_to_pointer_with_no_deref_info'
; CHECK: LV: Not vectorizing: Writes to memory unsupported in early exit loops.
diff --git a/llvm/test/Verifier/assume-bundles.ll b/llvm/test/Verifier/assume-bundles.ll
index 047e8d9bba3ed..d8037b965edb5 100644
--- a/llvm/test/Verifier/assume-bundles.ll
+++ b/llvm/test/Verifier/assume-bundles.ll
@@ -7,13 +7,13 @@ define void @func(ptr %P, i32 %P1, ptr %P2, ptr %P3) {
; CHECK: tags must be valid attribute names
; CHECK: "adazdazd"
call void @llvm.assume(i1 true) ["adazdazd"()]
-; CHECK: the second argument should be a constant integral value
+; CHECK-NOT: call{{.+}}deref
call void @llvm.assume(i1 true) ["dereferenceable"(ptr %P, i32 %P1)]
-; CHECK: the second argument should be a constant integral value
+; CHECK: second argument should be an integer
call void @llvm.assume(i1 true) ["dereferenceable"(ptr %P, float 1.5)]
-; CHECK: too many arguments
+; CHECK: dereferenceable assumptions should have 2 arguments
call void @llvm.assume(i1 true) ["dereferenceable"(ptr %P, i32 8, i32 8)]
-; CHECK: this attribute should have 2 arguments
+; CHECK: dereferenceable assumptions should have 2 arguments
call void @llvm.assume(i1 true) ["dereferenceable"(ptr %P)]
; CHECK: this attribute has no argument
call void @llvm.assume(i1 true) ["dereferenceable"(ptr %P, i32 4), "cold"(ptr %P)]
@@ -30,7 +30,7 @@ define void @func(ptr %P, i32 %P1, ptr %P2, ptr %P3) {
call void @llvm.assume(i1 true) ["separate_storage"(ptr %P)]
; CHECK: arguments to separate_storage assumptions should be pointers
call void @llvm.assume(i1 true) ["separate_storage"(ptr %P, i32 123)]
-; CHECK: this attribute should have 2 arguments
+; CHECK: dereferenceable assumptions should have 2 arguments
call void @llvm.assume(i1 true) ["align"(ptr %P, i32 4), "dereferenceable"(ptr %P)]
ret void
}
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