[llvm] Revert "[LoadStoreVectorizer] Postprocess and merge equivalence classes" (PR #119657)
via llvm-commits
llvm-commits at lists.llvm.org
Wed Dec 11 20:33:41 PST 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-vectorizers
Author: Michal Paszkowski (michalpaszkowski)
<details>
<summary>Changes</summary>
Reverts llvm/llvm-project#<!-- -->114501, due to the following failure: https://lab.llvm.org/buildbot/#/builders/55/builds/4171
---
Full diff: https://github.com/llvm/llvm-project/pull/119657.diff
2 Files Affected:
- (modified) llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp (-123)
- (removed) llvm/test/Transforms/LoadStoreVectorizer/X86/massive_indirection.ll (-142)
``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp b/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
index 9f24181d5d1f6d..02ec1d5c259cd6 100644
--- a/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
@@ -324,11 +324,6 @@ class Vectorizer {
Instruction *ChainElem, Instruction *ChainBegin,
const DenseMap<Instruction *, APInt /*OffsetFromLeader*/> &ChainOffsets);
- /// Merges the equivalence classes if they have underlying objects that differ
- /// by one level of indirection (i.e., one is a getelementptr and the other is
- /// the base pointer in that getelementptr).
- void mergeEquivalenceClasses(EquivalenceClassMap &EQClasses) const;
-
/// Collects loads and stores grouped by "equivalence class", where:
/// - all elements in an eq class are a load or all are a store,
/// - they all load/store the same element size (it's OK to have e.g. i8 and
@@ -1310,123 +1305,6 @@ std::optional<APInt> Vectorizer::getConstantOffsetSelects(
return std::nullopt;
}
-void Vectorizer::mergeEquivalenceClasses(EquivalenceClassMap &EQClasses) const {
- if (EQClasses.size() < 2) // There is nothing to merge.
- return;
-
- // The reduced key has all elements of the ECClassKey except the underlying
- // object. Check that EqClassKey has 4 elements and define the reduced key.
- static_assert(std::tuple_size_v<EqClassKey> == 4,
- "EqClassKey has changed - EqClassReducedKey needs changes too");
- using EqClassReducedKey =
- std::tuple<std::tuple_element_t<1, EqClassKey> /* AddrSpace */,
- std::tuple_element_t<2, EqClassKey> /* Element size */,
- std::tuple_element_t<3, EqClassKey> /* IsLoad; */>;
- using ECReducedKeyToUnderlyingObjectMap =
- MapVector<EqClassReducedKey,
- SmallPtrSet<std::tuple_element_t<0, EqClassKey>, 4>>;
-
- // Form a map from the reduced key (without the underlying object) to the
- // underlying objects: 1 reduced key to many underlying objects, to form
- // groups of potentially merge-able equivalence classes.
- ECReducedKeyToUnderlyingObjectMap RedKeyToUOMap;
- bool FoundPotentiallyOptimizableEC = false;
- for (const auto &EC : EQClasses) {
- const auto &Key = EC.first;
- EqClassReducedKey RedKey{std::get<1>(Key), std::get<2>(Key),
- std::get<3>(Key)};
- RedKeyToUOMap[RedKey].insert(std::get<0>(Key));
- if (RedKeyToUOMap[RedKey].size() > 1)
- FoundPotentiallyOptimizableEC = true;
- }
- if (!FoundPotentiallyOptimizableEC)
- return;
-
- LLVM_DEBUG({
- dbgs() << "LSV: mergeEquivalenceClasses: before merging:\n";
- for (const auto &EC : EQClasses) {
- dbgs() << " Key: ([" << std::get<0>(EC.first)
- << "]: " << *std::get<0>(EC.first) << ", " << std::get<1>(EC.first)
- << ", " << std::get<2>(EC.first) << ", "
- << static_cast<int>(std::get<3>(EC.first)) << ")\n";
- for (const auto &Inst : EC.second)
- dbgs() << "\tInst: " << *Inst << '\n';
- }
- });
- LLVM_DEBUG({
- dbgs() << "LSV: mergeEquivalenceClasses: RedKeyToUOMap:\n";
- for (const auto &RedKeyToUO : RedKeyToUOMap) {
- dbgs() << " Reduced key: (" << std::get<0>(RedKeyToUO.first) << ", "
- << std::get<1>(RedKeyToUO.first) << ", "
- << static_cast<int>(std::get<2>(RedKeyToUO.first)) << ") --> "
- << RedKeyToUO.second.size() << " underlying objects:\n";
- for (auto UObject : RedKeyToUO.second)
- dbgs() << " [" << UObject << "]: " << *UObject << '\n';
- }
- });
-
- using UObjectToUObjectMap = DenseMap<const Value *, const Value *>;
-
- // Compute the ultimate targets for a set of underlying objects.
- auto GetUltimateTargets =
- [](SmallPtrSetImpl<const Value *> &UObjects) -> UObjectToUObjectMap {
- UObjectToUObjectMap IndirectionMap;
- for (const auto *UObject : UObjects) {
- const unsigned MaxLookupDepth = 1; // look for 1-level indirections only
- const auto *UltimateTarget = getUnderlyingObject(UObject, MaxLookupDepth);
- if (UltimateTarget != UObject)
- IndirectionMap[UObject] = UltimateTarget;
- }
- UObjectToUObjectMap UltimateTargetsMap;
- for (const auto *UObject : UObjects) {
- auto Target = UObject;
- auto It = IndirectionMap.find(Target);
- for (; It != IndirectionMap.end(); It = IndirectionMap.find(Target))
- Target = It->second;
- UltimateTargetsMap[UObject] = Target;
- }
- return UltimateTargetsMap;
- };
-
- // For each item in RedKeyToUOMap, if it has more than one underlying object,
- // try to merge the equivalence classes.
- for (auto &[RedKey, UObjects] : RedKeyToUOMap) {
- if (UObjects.size() < 2)
- continue;
- auto UTMap = GetUltimateTargets(UObjects);
- for (const auto &[UObject, UltimateTarget] : UTMap) {
- if (UObject == UltimateTarget)
- continue;
-
- EqClassKey KeyFrom{UObject, std::get<0>(RedKey), std::get<1>(RedKey),
- std::get<2>(RedKey)};
- EqClassKey KeyTo{UltimateTarget, std::get<0>(RedKey), std::get<1>(RedKey),
- std::get<2>(RedKey)};
- const auto &VecFrom = EQClasses[KeyFrom];
- const auto &VecTo = EQClasses[KeyTo];
- SmallVector<Instruction *, 8> MergedVec;
- std::merge(VecFrom.begin(), VecFrom.end(), VecTo.begin(), VecTo.end(),
- std::back_inserter(MergedVec),
- [](Instruction *A, Instruction *B) {
- return A && B && A->comesBefore(B);
- });
- EQClasses[KeyTo] = std::move(MergedVec);
- EQClasses.erase(KeyFrom);
- }
- }
- LLVM_DEBUG({
- dbgs() << "LSV: mergeEquivalenceClasses: after merging:\n";
- for (const auto &EC : EQClasses) {
- dbgs() << " Key: ([" << std::get<0>(EC.first)
- << "]: " << *std::get<0>(EC.first) << ", " << std::get<1>(EC.first)
- << ", " << std::get<2>(EC.first) << ", "
- << static_cast<int>(std::get<3>(EC.first)) << ")\n";
- for (const auto &Inst : EC.second)
- dbgs() << "\tInst: " << *Inst << '\n';
- }
- });
-}
-
EquivalenceClassMap
Vectorizer::collectEquivalenceClasses(BasicBlock::iterator Begin,
BasicBlock::iterator End) {
@@ -1499,7 +1377,6 @@ Vectorizer::collectEquivalenceClasses(BasicBlock::iterator Begin,
.emplace_back(&I);
}
- mergeEquivalenceClasses(Ret);
return Ret;
}
diff --git a/llvm/test/Transforms/LoadStoreVectorizer/X86/massive_indirection.ll b/llvm/test/Transforms/LoadStoreVectorizer/X86/massive_indirection.ll
deleted file mode 100644
index c4b0d2e311d9d7..00000000000000
--- a/llvm/test/Transforms/LoadStoreVectorizer/X86/massive_indirection.ll
+++ /dev/null
@@ -1,142 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
-; RUN: opt %s -mtriple=x86_64-unknown-linux-gnu -passes=load-store-vectorizer -mcpu=skx -S -o - | FileCheck %s
-
-; This test verifies that the vectorizer can handle an extended sequence of
-; getelementptr instructions and generate longer vectors. With special handling,
-; some elements can still be vectorized even if they require looking up the
-; common underlying object deeper than 6 levels from the original pointer.
-
-; The test below is the simplified version of actual performance oriented
-; workload; the offsets in getelementptr instructions are similar or same for
-; the test simplicity.
-
-define void @v1_v2_v4_v1_to_v8_levels_6_7_8_8(i32 %arg0, ptr align 16 %arg1) {
-; CHECK-LABEL: define void @v1_v2_v4_v1_to_v8_levels_6_7_8_8(
-; CHECK-SAME: i32 [[ARG0:%.*]], ptr align 16 [[ARG1:%.*]]) #[[ATTR0:[0-9]+]] {
-; CHECK-NEXT: [[LEVEL1:%.*]] = getelementptr i8, ptr [[ARG1]], i32 917504
-; CHECK-NEXT: [[LEVEL2:%.*]] = getelementptr i8, ptr [[LEVEL1]], i32 [[ARG0]]
-; CHECK-NEXT: [[LEVEL3:%.*]] = getelementptr i8, ptr [[LEVEL2]], i32 32768
-; CHECK-NEXT: [[LEVEL4:%.*]] = getelementptr i8, ptr [[LEVEL3]], i32 [[ARG0]]
-; CHECK-NEXT: [[LEVEL5:%.*]] = getelementptr i8, ptr [[LEVEL4]], i32 [[ARG0]]
-; CHECK-NEXT: [[A6:%.*]] = getelementptr i8, ptr [[LEVEL5]], i32 [[ARG0]]
-; CHECK-NEXT: store <8 x half> zeroinitializer, ptr [[A6]], align 16
-; CHECK-NEXT: ret void
-;
-
- %level1 = getelementptr i8, ptr %arg1, i32 917504
- %level2 = getelementptr i8, ptr %level1, i32 %arg0
- %level3 = getelementptr i8, ptr %level2, i32 32768
- %level4 = getelementptr i8, ptr %level3, i32 %arg0
- %level5 = getelementptr i8, ptr %level4, i32 %arg0
-
- %a6 = getelementptr i8, ptr %level5, i32 %arg0
- %b7 = getelementptr i8, ptr %a6, i32 2
- %c8 = getelementptr i8, ptr %b7, i32 8
- %d8 = getelementptr i8, ptr %b7, i32 12
-
- store half 0xH0000, ptr %a6, align 16
- store <4 x half> zeroinitializer, ptr %b7, align 2
- store <2 x half> zeroinitializer, ptr %c8, align 2
- store half 0xH0000, ptr %d8, align 2
- ret void
-}
-
-define void @v1x8_levels_6_7_8_9_10_11_12_13(i32 %arg0, ptr align 16 %arg1) {
-; CHECK-LABEL: define void @v1x8_levels_6_7_8_9_10_11_12_13(
-; CHECK-SAME: i32 [[ARG0:%.*]], ptr align 16 [[ARG1:%.*]]) #[[ATTR0]] {
-; CHECK-NEXT: [[LEVEL1:%.*]] = getelementptr i8, ptr [[ARG1]], i32 917504
-; CHECK-NEXT: [[LEVEL2:%.*]] = getelementptr i8, ptr [[LEVEL1]], i32 [[ARG0]]
-; CHECK-NEXT: [[LEVEL3:%.*]] = getelementptr i8, ptr [[LEVEL2]], i32 32768
-; CHECK-NEXT: [[LEVEL4:%.*]] = getelementptr i8, ptr [[LEVEL3]], i32 [[ARG0]]
-; CHECK-NEXT: [[LEVEL5:%.*]] = getelementptr i8, ptr [[LEVEL4]], i32 [[ARG0]]
-; CHECK-NEXT: [[A6:%.*]] = getelementptr i8, ptr [[LEVEL5]], i32 [[ARG0]]
-; CHECK-NEXT: store <8 x half> zeroinitializer, ptr [[A6]], align 16
-; CHECK-NEXT: ret void
-;
-
- %level1 = getelementptr i8, ptr %arg1, i32 917504
- %level2 = getelementptr i8, ptr %level1, i32 %arg0
- %level3 = getelementptr i8, ptr %level2, i32 32768
- %level4 = getelementptr i8, ptr %level3, i32 %arg0
- %level5 = getelementptr i8, ptr %level4, i32 %arg0
-
- %a6 = getelementptr i8, ptr %level5, i32 %arg0
- %b7 = getelementptr i8, ptr %a6, i32 2
- %c8 = getelementptr i8, ptr %b7, i32 2
- %d9 = getelementptr i8, ptr %c8, i32 2
- %e10 = getelementptr i8, ptr %d9, i32 2
- %f11 = getelementptr i8, ptr %e10, i32 2
- %g12 = getelementptr i8, ptr %f11, i32 2
- %h13 = getelementptr i8, ptr %g12, i32 2
-
- store half 0xH0000, ptr %a6, align 16
- store half 0xH0000, ptr %b7, align 2
- store half 0xH0000, ptr %c8, align 2
- store half 0xH0000, ptr %d9, align 2
- store half 0xH0000, ptr %e10, align 8
- store half 0xH0000, ptr %f11, align 2
- store half 0xH0000, ptr %g12, align 2
- store half 0xH0000, ptr %h13, align 2
- ret void
-}
-
-define void @v1_4_4_4_2_1_to_v8_8_levels_6_7(i32 %arg0, ptr addrspace(3) align 16 %arg1_ptr, i32 %arg2, i32 %arg3, i32 %arg4, i32 %arg5, half %arg6_half, half %arg7_half, <2 x half> %arg8_2xhalf) {
-; CHECK-LABEL: define void @v1_4_4_4_2_1_to_v8_8_levels_6_7(
-; CHECK-SAME: i32 [[ARG0:%.*]], ptr addrspace(3) align 16 [[ARG1_PTR:%.*]], i32 [[ARG2:%.*]], i32 [[ARG3:%.*]], i32 [[ARG4:%.*]], i32 [[ARG5:%.*]], half [[ARG6_HALF:%.*]], half [[ARG7_HALF:%.*]], <2 x half> [[ARG8_2XHALF:%.*]]) #[[ATTR0]] {
-; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds i8, ptr addrspace(3) [[ARG1_PTR]], i32 458752
-; CHECK-NEXT: br [[DOTPREHEADER11_PREHEADER:label %.*]]
-; CHECK: [[_PREHEADER11_PREHEADER:.*:]]
-; CHECK-NEXT: [[TMP2:%.*]] = shl nuw nsw i32 [[ARG0]], 6
-; CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i8, ptr addrspace(3) [[TMP1]], i32 [[TMP2]]
-; CHECK-NEXT: [[TMP4:%.*]] = getelementptr inbounds i8, ptr addrspace(3) [[TMP3]], i32 [[ARG2]]
-; CHECK-NEXT: [[TMP5:%.*]] = getelementptr inbounds i8, ptr addrspace(3) [[TMP4]], i32 [[ARG3]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[ARG0]], 2
-; CHECK-NEXT: br i1 [[CMP]], [[DOTLR_PH:label %.*]], [[DOTEXIT_POINT:label %.*]]
-; CHECK: [[_LR_PH:.*:]]
-; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, ptr addrspace(3) [[TMP5]], i32 [[ARG4]]
-; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i8, ptr addrspace(3) [[GEP]], i32 [[ARG5]]
-; CHECK-NEXT: [[TMP7:%.*]] = insertelement <8 x half> poison, half [[ARG6_HALF]], i32 0
-; CHECK-NEXT: [[TMP8:%.*]] = insertelement <8 x half> [[TMP7]], half 0xH0000, i32 1
-; CHECK-NEXT: [[TMP9:%.*]] = insertelement <8 x half> [[TMP8]], half 0xH0000, i32 2
-; CHECK-NEXT: [[TMP10:%.*]] = insertelement <8 x half> [[TMP9]], half 0xH0000, i32 3
-; CHECK-NEXT: [[TMP11:%.*]] = insertelement <8 x half> [[TMP10]], half 0xH0000, i32 4
-; CHECK-NEXT: [[TMP12:%.*]] = extractelement <2 x half> [[ARG8_2XHALF]], i32 0
-; CHECK-NEXT: [[TMP13:%.*]] = insertelement <8 x half> [[TMP11]], half [[TMP12]], i32 5
-; CHECK-NEXT: [[TMP14:%.*]] = extractelement <2 x half> [[ARG8_2XHALF]], i32 1
-; CHECK-NEXT: [[TMP15:%.*]] = insertelement <8 x half> [[TMP13]], half [[TMP14]], i32 6
-; CHECK-NEXT: [[TMP16:%.*]] = insertelement <8 x half> [[TMP15]], half [[ARG7_HALF]], i32 7
-; CHECK-NEXT: store <8 x half> [[TMP16]], ptr addrspace(3) [[TMP6]], align 2
-; CHECK-NEXT: br [[DOTEXIT_POINT]]
-; CHECK: [[_EXIT_POINT:.*:]]
-; CHECK-NEXT: ret void
-;
- %base1 = getelementptr inbounds i8, ptr addrspace(3) %arg1_ptr, i32 458752
- br label %.preheader11.preheader
-
-.preheader11.preheader:
- %base2 = shl nuw nsw i32 %arg0, 6
- %base3 = getelementptr inbounds i8, ptr addrspace(3) %base1, i32 %base2
-
- %base4 = getelementptr inbounds i8, ptr addrspace(3) %base3, i32 %arg2
- %base5 = getelementptr inbounds i8, ptr addrspace(3) %base4, i32 %arg3
-
- %cmp = icmp sgt i32 %arg0, 2
- br i1 %cmp, label %.lr.ph, label %.exit_point
-
-.lr.ph:
- %gep = getelementptr inbounds i8, ptr addrspace(3) %base5, i32 %arg4
-
- %dst = getelementptr inbounds i8, ptr addrspace(3) %gep, i32 %arg5
- %dst_off2 = getelementptr inbounds i8, ptr addrspace(3) %dst, i32 2
- %dst_off10 = getelementptr inbounds i8, ptr addrspace(3) %dst, i32 10
- %dst_off14 = getelementptr inbounds i8, ptr addrspace(3) %dst, i32 14
-
- store half %arg6_half, ptr addrspace(3) %dst, align 2
- store <4 x half> zeroinitializer, ptr addrspace(3) %dst_off2, align 2
- store <2 x half> %arg8_2xhalf, ptr addrspace(3) %dst_off10, align 2
- store half %arg7_half, ptr addrspace(3) %dst_off14, align 2
- br label %.exit_point
-
-.exit_point:
- ret void
-}
``````````
</details>
https://github.com/llvm/llvm-project/pull/119657
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