[llvm] 682e739 - [LV] Fix FoldTail under user VF and UF
Ayal Zaks via llvm-commits
llvm-commits at lists.llvm.org
Mon May 18 15:48:05 PDT 2020
Author: Ayal Zaks
Date: 2020-05-19T01:32:25+03:00
New Revision: 682e739638a9c569d4c5c358ab75365175a95efc
URL: https://github.com/llvm/llvm-project/commit/682e739638a9c569d4c5c358ab75365175a95efc
DIFF: https://github.com/llvm/llvm-project/commit/682e739638a9c569d4c5c358ab75365175a95efc.diff
LOG: [LV] Fix FoldTail under user VF and UF
LV considers an internally computed MaxVF to decide if a constant trip-count is
a multiple of any subsequently chosen VF, and conclude that no scalar remainder
iterations (tail) will be left for Fold Tail to handle. If an external VF is
provided via -force-vector-width, it must be considered instead of the internal
MaxVF.
If an external UF is provided via -force-vector-interleave, it too must be
considered in addition to MaxVF or user VF.
Fixes PR45679.
Differential Revision: https://reviews.llvm.org/D80085
Added:
llvm/test/Transforms/LoopVectorize/pr45679-fold-tail-by-masking.ll
Modified:
llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h b/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
index 491dc08bfa49..8dd06983cd84 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
@@ -241,7 +241,7 @@ class LoopVectorizationPlanner {
/// Plan how to best vectorize, return the best VF and its cost, or None if
/// vectorization and interleaving should be avoided up front.
- Optional<VectorizationFactor> plan(unsigned UserVF);
+ Optional<VectorizationFactor> plan(unsigned UserVF, unsigned UserIC);
/// Use the VPlan-native path to plan how to best vectorize, return the best
/// VF and its cost.
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 1d9d617c93b2..9c47e6267af7 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -975,7 +975,7 @@ class LoopVectorizationCostModel {
/// \return An upper bound for the vectorization factor, or None if
/// vectorization and interleaving should be avoided up front.
- Optional<unsigned> computeMaxVF();
+ Optional<unsigned> computeMaxVF(unsigned UserVF, unsigned UserIC);
/// \return True if runtime checks are required for vectorization, and false
/// otherwise.
@@ -4942,7 +4942,8 @@ bool LoopVectorizationCostModel::runtimeChecksRequired() {
return false;
}
-Optional<unsigned> LoopVectorizationCostModel::computeMaxVF() {
+Optional<unsigned> LoopVectorizationCostModel::computeMaxVF(unsigned UserVF,
+ unsigned UserIC) {
if (Legal->getRuntimePointerChecking()->Need && TTI.hasBranchDivergence()) {
// TODO: It may by useful to do since it's still likely to be dynamically
// uniform if the target can skip.
@@ -4964,7 +4965,7 @@ Optional<unsigned> LoopVectorizationCostModel::computeMaxVF() {
switch (ScalarEpilogueStatus) {
case CM_ScalarEpilogueAllowed:
- return computeFeasibleMaxVF(TC);
+ return UserVF ? UserVF : computeFeasibleMaxVF(TC);
case CM_ScalarEpilogueNotNeededUsePredicate:
LLVM_DEBUG(
dbgs() << "LV: vector predicate hint/switch found.\n"
@@ -5000,8 +5001,9 @@ Optional<unsigned> LoopVectorizationCostModel::computeMaxVF() {
InterleaveInfo.invalidateGroupsRequiringScalarEpilogue();
}
- unsigned MaxVF = computeFeasibleMaxVF(TC);
- if (TC > 0 && TC % MaxVF == 0) {
+ unsigned MaxVF = UserVF ? UserVF : computeFeasibleMaxVF(TC);
+ unsigned MaxVFtimesIC = UserIC ? MaxVF * UserIC : MaxVF;
+ if (TC > 0 && TC % MaxVFtimesIC == 0) {
// Accept MaxVF if we do not have a tail.
LLVM_DEBUG(dbgs() << "LV: No tail will remain for any chosen VF.\n");
return MaxVF;
@@ -6546,9 +6548,10 @@ LoopVectorizationPlanner::planInVPlanNativePath(unsigned UserVF) {
return VectorizationFactor::Disabled();
}
-Optional<VectorizationFactor> LoopVectorizationPlanner::plan(unsigned UserVF) {
+Optional<VectorizationFactor> LoopVectorizationPlanner::plan(unsigned UserVF,
+ unsigned UserIC) {
assert(OrigLoop->empty() && "Inner loop expected.");
- Optional<unsigned> MaybeMaxVF = CM.computeMaxVF();
+ Optional<unsigned> MaybeMaxVF = CM.computeMaxVF(UserVF, UserIC);
if (!MaybeMaxVF) // Cases that should not to be vectorized nor interleaved.
return None;
@@ -7810,15 +7813,15 @@ bool LoopVectorizePass::processLoop(Loop *L) {
// Use the planner for vectorization.
LoopVectorizationPlanner LVP(L, LI, TLI, TTI, &LVL, CM, IAI, PSE);
- // Get user vectorization factor.
+ // Get user vectorization factor and interleave count.
unsigned UserVF = Hints.getWidth();
+ unsigned UserIC = Hints.getInterleave();
// Plan how to best vectorize, return the best VF and its cost.
- Optional<VectorizationFactor> MaybeVF = LVP.plan(UserVF);
+ Optional<VectorizationFactor> MaybeVF = LVP.plan(UserVF, UserIC);
VectorizationFactor VF = VectorizationFactor::Disabled();
unsigned IC = 1;
- unsigned UserIC = Hints.getInterleave();
if (MaybeVF) {
VF = *MaybeVF;
diff --git a/llvm/test/Transforms/LoopVectorize/pr45679-fold-tail-by-masking.ll b/llvm/test/Transforms/LoopVectorize/pr45679-fold-tail-by-masking.ll
new file mode 100644
index 000000000000..835a6dad3206
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/pr45679-fold-tail-by-masking.ll
@@ -0,0 +1,148 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -loop-vectorize -force-vector-width=4 -S | FileCheck %s
+; RUN: opt < %s -loop-vectorize -force-vector-width=2 -force-vector-interleave=2 -S | FileCheck %s -check-prefix=VF2UF2
+
+target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"
+
+; Make sure a loop is vectorized correctly with fold-tail when the constant
+; trip-count is not a multiple of -force-vector-width and/or
+; -force-vector-interleave, but is a multiple of the internally computed MaxVF;
+; e.g., when all types are i32 lead to MaxVF=1.
+
+define void @pr45679(i32* %A) optsize {
+; CHECK-LABEL: @pr45679(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; CHECK: vector.ph:
+; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
+; CHECK: vector.body:
+; CHECK-NEXT: [[INDEX:%.*]] = phi i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[PRED_STORE_CONTINUE6:%.*]] ]
+; CHECK-NEXT: [[VEC_IND:%.*]] = phi <4 x i32> [ <i32 0, i32 1, i32 2, i32 3>, [[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], [[PRED_STORE_CONTINUE6]] ]
+; CHECK-NEXT: [[TMP0:%.*]] = icmp ule <4 x i32> [[VEC_IND]], <i32 13, i32 13, i32 13, i32 13>
+; CHECK-NEXT: [[TMP1:%.*]] = extractelement <4 x i1> [[TMP0]], i32 0
+; CHECK-NEXT: br i1 [[TMP1]], label [[PRED_STORE_IF:%.*]], label [[PRED_STORE_CONTINUE:%.*]]
+; CHECK: pred.store.if:
+; CHECK-NEXT: [[TMP2:%.*]] = add i32 [[INDEX]], 0
+; CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i32, i32* [[A:%.*]], i32 [[TMP2]]
+; CHECK-NEXT: store i32 13, i32* [[TMP3]], align 1
+; CHECK-NEXT: br label [[PRED_STORE_CONTINUE]]
+; CHECK: pred.store.continue:
+; CHECK-NEXT: [[TMP4:%.*]] = extractelement <4 x i1> [[TMP0]], i32 1
+; CHECK-NEXT: br i1 [[TMP4]], label [[PRED_STORE_IF1:%.*]], label [[PRED_STORE_CONTINUE2:%.*]]
+; CHECK: pred.store.if1:
+; CHECK-NEXT: [[TMP5:%.*]] = add i32 [[INDEX]], 1
+; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i32, i32* [[A]], i32 [[TMP5]]
+; CHECK-NEXT: store i32 13, i32* [[TMP6]], align 1
+; CHECK-NEXT: br label [[PRED_STORE_CONTINUE2]]
+; CHECK: pred.store.continue2:
+; CHECK-NEXT: [[TMP7:%.*]] = extractelement <4 x i1> [[TMP0]], i32 2
+; CHECK-NEXT: br i1 [[TMP7]], label [[PRED_STORE_IF3:%.*]], label [[PRED_STORE_CONTINUE4:%.*]]
+; CHECK: pred.store.if3:
+; CHECK-NEXT: [[TMP8:%.*]] = add i32 [[INDEX]], 2
+; CHECK-NEXT: [[TMP9:%.*]] = getelementptr inbounds i32, i32* [[A]], i32 [[TMP8]]
+; CHECK-NEXT: store i32 13, i32* [[TMP9]], align 1
+; CHECK-NEXT: br label [[PRED_STORE_CONTINUE4]]
+; CHECK: pred.store.continue4:
+; CHECK-NEXT: [[TMP10:%.*]] = extractelement <4 x i1> [[TMP0]], i32 3
+; CHECK-NEXT: br i1 [[TMP10]], label [[PRED_STORE_IF5:%.*]], label [[PRED_STORE_CONTINUE6]]
+; CHECK: pred.store.if5:
+; CHECK-NEXT: [[TMP11:%.*]] = add i32 [[INDEX]], 3
+; CHECK-NEXT: [[TMP12:%.*]] = getelementptr inbounds i32, i32* [[A]], i32 [[TMP11]]
+; CHECK-NEXT: store i32 13, i32* [[TMP12]], align 1
+; CHECK-NEXT: br label [[PRED_STORE_CONTINUE6]]
+; CHECK: pred.store.continue6:
+; CHECK-NEXT: [[INDEX_NEXT]] = add i32 [[INDEX]], 4
+; CHECK-NEXT: [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], <i32 4, i32 4, i32 4, i32 4>
+; CHECK-NEXT: [[TMP13:%.*]] = icmp eq i32 [[INDEX_NEXT]], 16
+; CHECK-NEXT: br i1 [[TMP13]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop !0
+; CHECK: middle.block:
+; CHECK-NEXT: br i1 true, label [[EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK: scalar.ph:
+; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ 16, [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT: br label [[LOOP:%.*]]
+; CHECK: loop:
+; CHECK-NEXT: [[RIV:%.*]] = phi i32 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[RIVPLUS1:%.*]], [[LOOP]] ]
+; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i32, i32* [[A]], i32 [[RIV]]
+; CHECK-NEXT: store i32 13, i32* [[ARRAYIDX]], align 1
+; CHECK-NEXT: [[RIVPLUS1]] = add nuw nsw i32 [[RIV]], 1
+; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[RIVPLUS1]], 14
+; CHECK-NEXT: br i1 [[COND]], label [[EXIT]], label [[LOOP]], !llvm.loop !2
+; CHECK: exit:
+; CHECK-NEXT: ret void
+;
+; VF2UF2-LABEL: @pr45679(
+; VF2UF2-NEXT: entry:
+; VF2UF2-NEXT: br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; VF2UF2: vector.ph:
+; VF2UF2-NEXT: br label [[VECTOR_BODY:%.*]]
+; VF2UF2: vector.body:
+; VF2UF2-NEXT: [[INDEX:%.*]] = phi i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[PRED_STORE_CONTINUE7:%.*]] ]
+; VF2UF2-NEXT: [[VEC_IND:%.*]] = phi <2 x i32> [ <i32 0, i32 1>, [[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], [[PRED_STORE_CONTINUE7]] ]
+; VF2UF2-NEXT: [[STEP_ADD:%.*]] = add <2 x i32> [[VEC_IND]], <i32 2, i32 2>
+; VF2UF2-NEXT: [[TMP0:%.*]] = icmp ule <2 x i32> [[VEC_IND]], <i32 13, i32 13>
+; VF2UF2-NEXT: [[TMP1:%.*]] = icmp ule <2 x i32> [[STEP_ADD]], <i32 13, i32 13>
+; VF2UF2-NEXT: [[TMP2:%.*]] = extractelement <2 x i1> [[TMP0]], i32 0
+; VF2UF2-NEXT: br i1 [[TMP2]], label [[PRED_STORE_IF:%.*]], label [[PRED_STORE_CONTINUE:%.*]]
+; VF2UF2: pred.store.if:
+; VF2UF2-NEXT: [[TMP3:%.*]] = add i32 [[INDEX]], 0
+; VF2UF2-NEXT: [[TMP4:%.*]] = getelementptr inbounds i32, i32* [[A:%.*]], i32 [[TMP3]]
+; VF2UF2-NEXT: store i32 13, i32* [[TMP4]], align 1
+; VF2UF2-NEXT: br label [[PRED_STORE_CONTINUE]]
+; VF2UF2: pred.store.continue:
+; VF2UF2-NEXT: [[TMP5:%.*]] = extractelement <2 x i1> [[TMP0]], i32 1
+; VF2UF2-NEXT: br i1 [[TMP5]], label [[PRED_STORE_IF2:%.*]], label [[PRED_STORE_CONTINUE3:%.*]]
+; VF2UF2: pred.store.if2:
+; VF2UF2-NEXT: [[TMP6:%.*]] = add i32 [[INDEX]], 1
+; VF2UF2-NEXT: [[TMP7:%.*]] = getelementptr inbounds i32, i32* [[A]], i32 [[TMP6]]
+; VF2UF2-NEXT: store i32 13, i32* [[TMP7]], align 1
+; VF2UF2-NEXT: br label [[PRED_STORE_CONTINUE3]]
+; VF2UF2: pred.store.continue3:
+; VF2UF2-NEXT: [[TMP8:%.*]] = extractelement <2 x i1> [[TMP1]], i32 0
+; VF2UF2-NEXT: br i1 [[TMP8]], label [[PRED_STORE_IF4:%.*]], label [[PRED_STORE_CONTINUE5:%.*]]
+; VF2UF2: pred.store.if4:
+; VF2UF2-NEXT: [[TMP9:%.*]] = add i32 [[INDEX]], 2
+; VF2UF2-NEXT: [[TMP10:%.*]] = getelementptr inbounds i32, i32* [[A]], i32 [[TMP9]]
+; VF2UF2-NEXT: store i32 13, i32* [[TMP10]], align 1
+; VF2UF2-NEXT: br label [[PRED_STORE_CONTINUE5]]
+; VF2UF2: pred.store.continue5:
+; VF2UF2-NEXT: [[TMP11:%.*]] = extractelement <2 x i1> [[TMP1]], i32 1
+; VF2UF2-NEXT: br i1 [[TMP11]], label [[PRED_STORE_IF6:%.*]], label [[PRED_STORE_CONTINUE7]]
+; VF2UF2: pred.store.if6:
+; VF2UF2-NEXT: [[TMP12:%.*]] = add i32 [[INDEX]], 3
+; VF2UF2-NEXT: [[TMP13:%.*]] = getelementptr inbounds i32, i32* [[A]], i32 [[TMP12]]
+; VF2UF2-NEXT: store i32 13, i32* [[TMP13]], align 1
+; VF2UF2-NEXT: br label [[PRED_STORE_CONTINUE7]]
+; VF2UF2: pred.store.continue7:
+; VF2UF2-NEXT: [[INDEX_NEXT]] = add i32 [[INDEX]], 4
+; VF2UF2-NEXT: [[VEC_IND_NEXT]] = add <2 x i32> [[STEP_ADD]], <i32 2, i32 2>
+; VF2UF2-NEXT: [[TMP14:%.*]] = icmp eq i32 [[INDEX_NEXT]], 16
+; VF2UF2-NEXT: br i1 [[TMP14]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop !0
+; VF2UF2: middle.block:
+; VF2UF2-NEXT: br i1 true, label [[EXIT:%.*]], label [[SCALAR_PH]]
+; VF2UF2: scalar.ph:
+; VF2UF2-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ 16, [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
+; VF2UF2-NEXT: br label [[LOOP:%.*]]
+; VF2UF2: loop:
+; VF2UF2-NEXT: [[RIV:%.*]] = phi i32 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[RIVPLUS1:%.*]], [[LOOP]] ]
+; VF2UF2-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i32, i32* [[A]], i32 [[RIV]]
+; VF2UF2-NEXT: store i32 13, i32* [[ARRAYIDX]], align 1
+; VF2UF2-NEXT: [[RIVPLUS1]] = add nuw nsw i32 [[RIV]], 1
+; VF2UF2-NEXT: [[COND:%.*]] = icmp eq i32 [[RIVPLUS1]], 14
+; VF2UF2-NEXT: br i1 [[COND]], label [[EXIT]], label [[LOOP]], !llvm.loop !2
+; VF2UF2: exit:
+; VF2UF2-NEXT: ret void
+;
+entry:
+ br label %loop
+
+loop:
+ %riv = phi i32 [ 0, %entry ], [ %rivPlus1, %loop ]
+ %arrayidx = getelementptr inbounds i32, i32* %A, i32 %riv
+ store i32 13, i32* %arrayidx, align 1
+ %rivPlus1 = add nuw nsw i32 %riv, 1
+ %cond = icmp eq i32 %rivPlus1, 14
+ br i1 %cond, label %exit, label %loop
+
+exit:
+ ret void
+}
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