[llvm] [LoopVectorize] Use predicated version of getSmallConstantMaxTripCount (PR #109928)
via llvm-commits
llvm-commits at lists.llvm.org
Wed Sep 25 01:36:15 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms
Author: David Sherwood (david-arm)
<details>
<summary>Changes</summary>
There are a number of places where we call getSmallConstantMaxTripCount
without passing a vector of predicates:
getSmallBestKnownTC
isIndvarOverflowCheckKnownFalse
computeMaxVF
isMoreProfitable
I've changed all of these to now pass in a predicate vector so that
we get the benefit of making better vectorisation choices when we
know the max trip count for loops that require SCEV predicate checks.
I've tried to add tests that cover all the cases affected by these
changes.
---
Patch is 27.39 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/109928.diff
3 Files Affected:
- (modified) llvm/lib/Transforms/Vectorize/LoopVectorize.cpp (+14-5)
- (added) llvm/test/Transforms/LoopVectorize/AArch64/low_trip_count_predicates.ll (+405)
- (modified) llvm/test/Transforms/LoopVectorize/RISCV/riscv-vector-reverse.ll (+2)
``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 0566d80c1cc001..55b59458a0aa41 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -422,7 +422,8 @@ static std::optional<unsigned> getSmallBestKnownTC(ScalarEvolution &SE,
return *EstimatedTC;
// Check if upper bound estimate is known.
- if (unsigned ExpectedTC = SE.getSmallConstantMaxTripCount(L))
+ SmallVector<const SCEVPredicate *, 2> Predicates;
+ if (unsigned ExpectedTC = SE.getSmallConstantMaxTripCount(L, &Predicates))
return ExpectedTC;
return std::nullopt;
@@ -2298,8 +2299,9 @@ static bool isIndvarOverflowCheckKnownFalse(
// We know the runtime overflow check is known false iff the (max) trip-count
// is known and (max) trip-count + (VF * UF) does not overflow in the type of
// the vector loop induction variable.
- if (unsigned TC =
- Cost->PSE.getSE()->getSmallConstantMaxTripCount(Cost->TheLoop)) {
+ SmallVector<const SCEVPredicate *, 2> Predicates;
+ if (unsigned TC = Cost->PSE.getSE()->getSmallConstantMaxTripCount(
+ Cost->TheLoop, &Predicates)) {
uint64_t MaxVF = VF.getKnownMinValue();
if (VF.isScalable()) {
std::optional<unsigned> MaxVScale =
@@ -3994,8 +3996,13 @@ LoopVectorizationCostModel::computeMaxVF(ElementCount UserVF, unsigned UserIC) {
}
unsigned TC = PSE.getSE()->getSmallConstantTripCount(TheLoop);
- unsigned MaxTC = PSE.getSE()->getSmallConstantMaxTripCount(TheLoop);
+
+ SmallVector<const SCEVPredicate *, 2> Predicates;
+ unsigned MaxTC =
+ PSE.getSE()->getSmallConstantMaxTripCount(TheLoop, &Predicates);
LLVM_DEBUG(dbgs() << "LV: Found trip count: " << TC << '\n');
+ if (TC != MaxTC)
+ LLVM_DEBUG(dbgs() << "LV: Found maximum trip count: " << MaxTC << '\n');
if (TC == 1) {
reportVectorizationFailure("Single iteration (non) loop",
"loop trip count is one, irrelevant for vectorization",
@@ -4283,7 +4290,9 @@ bool LoopVectorizationPlanner::isMoreProfitable(
InstructionCost CostA = A.Cost;
InstructionCost CostB = B.Cost;
- unsigned MaxTripCount = PSE.getSE()->getSmallConstantMaxTripCount(OrigLoop);
+ SmallVector<const SCEVPredicate *, 2> Predicates;
+ unsigned MaxTripCount =
+ PSE.getSE()->getSmallConstantMaxTripCount(OrigLoop, &Predicates);
// Improve estimate for the vector width if it is scalable.
unsigned EstimatedWidthA = A.Width.getKnownMinValue();
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/low_trip_count_predicates.ll b/llvm/test/Transforms/LoopVectorize/AArch64/low_trip_count_predicates.ll
new file mode 100644
index 00000000000000..2cdfa0d1564219
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/low_trip_count_predicates.ll
@@ -0,0 +1,405 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; REQUIRES: asserts
+; RUN: opt -S < %s -p loop-vectorize -debug-only=loop-vectorize -mattr=+sve 2>%t | FileCheck %s
+; RUN: cat %t | FileCheck %s --check-prefix=DEBUG
+
+target triple = "aarch64-unknown-linux-gnu"
+
+; DEBUG-LABEL: LV: Checking a loop in 'low_vf_ic_is_better'
+; DEBUG: LV: Found trip count: 0
+; DEBUG: LV: Found maximum trip count: 19
+; DEBUG: LV: IC is 1
+; DEBUG: LV: VF is vscale x 8
+; DEBUG: Main Loop VF:vscale x 8, Main Loop UF:1, Epilogue Loop VF:vscale x 4, Epilogue Loop UF:1
+
+; DEBUG-LABEL: LV: Checking a loop in 'trip_count_too_small'
+; DEBUG: LV: Found a loop with a very small trip count. This loop is worth vectorizing only if no scalar iteration overheads are incurred.
+; DEBUG: LV: Not vectorizing: The trip count is below the minial threshold value..
+
+; DEBUG-LABEL: LV: Checking a loop in 'too_many_runtime_checks'
+; DEBUG: LV: Found trip count: 0
+; DEBUG: LV: Found maximum trip count: 16
+; DEBUG: LV: Clamping the MaxVF to maximum power of two not exceeding the constant trip count: 16
+; DEBUG: LV: IC is 1
+; DEBUG: LV: VF is 16
+; DEBUG: LV: Vectorization is not beneficial: expected trip count < minimum profitable VF (16 < 32)
+; DEBUG: LV: Too many memory checks needed.
+
+; DEBUG-LABEL: LV: Checking a loop in 'overflow_indvar_known_false'
+; DEBUG: LV: Found trip count: 0
+; DEBUG: LV: Found maximum trip count: 1027
+; DEBUG: LV: can fold tail by masking.
+; DEBUG: Executing best plan with VF=vscale x 16, UF=1
+
+define void @low_vf_ic_is_better(ptr nocapture noundef %p, i16 noundef %val) {
+; CHECK-LABEL: define void @low_vf_ic_is_better(
+; CHECK-SAME: ptr nocapture noundef [[P:%.*]], i16 noundef [[VAL:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT: [[ENTRY:.*:]]
+; CHECK-NEXT: [[P_PROMOTED:%.*]] = load i32, ptr [[P]], align 4
+; CHECK-NEXT: [[CMP7:%.*]] = icmp ult i32 [[P_PROMOTED]], 19
+; CHECK-NEXT: br i1 [[CMP7]], label %[[ITER_CHECK:.*]], label %[[WHILE_END:.*]]
+; CHECK: [[ITER_CHECK]]:
+; CHECK-NEXT: [[CONV:%.*]] = trunc i16 [[VAL]] to i8
+; CHECK-NEXT: [[V:%.*]] = getelementptr inbounds nuw i8, ptr [[P]], i64 4
+; CHECK-NEXT: [[TMP0:%.*]] = zext nneg i32 [[P_PROMOTED]] to i64
+; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[P_PROMOTED]], 1
+; CHECK-NEXT: [[TMP2:%.*]] = zext i32 [[TMP1]] to i64
+; CHECK-NEXT: [[TMP3:%.*]] = sub i64 20, [[TMP2]]
+; CHECK-NEXT: [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT: [[TMP5:%.*]] = mul i64 [[TMP4]], 4
+; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP3]], [[TMP5]]
+; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label %[[VEC_EPILOG_SCALAR_PH:.*]], label %[[VECTOR_SCEVCHECK:.*]]
+; CHECK: [[VECTOR_SCEVCHECK]]:
+; CHECK-NEXT: [[TMP6:%.*]] = add i32 [[P_PROMOTED]], 1
+; CHECK-NEXT: [[TMP7:%.*]] = zext i32 [[TMP6]] to i64
+; CHECK-NEXT: [[TMP8:%.*]] = sub i64 19, [[TMP7]]
+; CHECK-NEXT: [[TMP9:%.*]] = trunc i64 [[TMP8]] to i32
+; CHECK-NEXT: [[TMP10:%.*]] = add i32 [[TMP6]], [[TMP9]]
+; CHECK-NEXT: [[TMP11:%.*]] = icmp ult i32 [[TMP10]], [[TMP6]]
+; CHECK-NEXT: [[TMP12:%.*]] = icmp ugt i64 [[TMP8]], 4294967295
+; CHECK-NEXT: [[TMP13:%.*]] = or i1 [[TMP11]], [[TMP12]]
+; CHECK-NEXT: br i1 [[TMP13]], label %[[VEC_EPILOG_SCALAR_PH]], label %[[VECTOR_MAIN_LOOP_ITER_CHECK:.*]]
+; CHECK: [[VECTOR_MAIN_LOOP_ITER_CHECK]]:
+; CHECK-NEXT: [[TMP14:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT: [[TMP15:%.*]] = mul i64 [[TMP14]], 8
+; CHECK-NEXT: [[MIN_ITERS_CHECK1:%.*]] = icmp ult i64 [[TMP3]], [[TMP15]]
+; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK1]], label %[[VEC_EPILOG_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK: [[VECTOR_PH]]:
+; CHECK-NEXT: [[TMP16:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT: [[TMP17:%.*]] = mul i64 [[TMP16]], 8
+; CHECK-NEXT: [[N_MOD_VF:%.*]] = urem i64 [[TMP3]], [[TMP17]]
+; CHECK-NEXT: [[N_VEC:%.*]] = sub i64 [[TMP3]], [[N_MOD_VF]]
+; CHECK-NEXT: [[TMP18:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT: [[TMP19:%.*]] = mul i64 [[TMP18]], 8
+; CHECK-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 8 x i8> poison, i8 [[CONV]], i64 0
+; CHECK-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 8 x i8> [[BROADCAST_SPLATINSERT]], <vscale x 8 x i8> poison, <vscale x 8 x i32> zeroinitializer
+; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
+; CHECK: [[VECTOR_BODY]]:
+; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT: [[OFFSET_IDX:%.*]] = add i64 [[TMP0]], [[INDEX]]
+; CHECK-NEXT: [[TMP20:%.*]] = add i64 [[OFFSET_IDX]], 0
+; CHECK-NEXT: [[TMP21:%.*]] = getelementptr inbounds [100 x i8], ptr [[V]], i64 0, i64 [[TMP20]]
+; CHECK-NEXT: [[TMP22:%.*]] = getelementptr inbounds i8, ptr [[TMP21]], i32 0
+; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <vscale x 8 x i8>, ptr [[TMP22]], align 1
+; CHECK-NEXT: [[TMP23:%.*]] = add <vscale x 8 x i8> [[WIDE_LOAD]], [[BROADCAST_SPLAT]]
+; CHECK-NEXT: store <vscale x 8 x i8> [[TMP23]], ptr [[TMP22]], align 1
+; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP19]]
+; CHECK-NEXT: [[TMP31:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[TMP31]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK: [[MIDDLE_BLOCK]]:
+; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[TMP3]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[CMP_N]], label %[[WHILE_END_LOOPEXIT:.*]], label %[[VEC_EPILOG_ITER_CHECK:.*]]
+; CHECK: [[VEC_EPILOG_ITER_CHECK]]:
+; CHECK-NEXT: [[IND_END5:%.*]] = add i64 [[TMP0]], [[N_VEC]]
+; CHECK-NEXT: [[N_VEC_REMAINING:%.*]] = sub i64 [[TMP3]], [[N_VEC]]
+; CHECK-NEXT: [[TMP32:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT: [[TMP33:%.*]] = mul i64 [[TMP32]], 4
+; CHECK-NEXT: [[MIN_EPILOG_ITERS_CHECK:%.*]] = icmp ult i64 [[N_VEC_REMAINING]], [[TMP33]]
+; CHECK-NEXT: br i1 [[MIN_EPILOG_ITERS_CHECK]], label %[[VEC_EPILOG_SCALAR_PH]], label %[[VEC_EPILOG_PH]]
+; CHECK: [[VEC_EPILOG_PH]]:
+; CHECK-NEXT: [[VEC_EPILOG_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[VEC_EPILOG_ITER_CHECK]] ], [ 0, %[[VECTOR_MAIN_LOOP_ITER_CHECK]] ]
+; CHECK-NEXT: [[TMP34:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT: [[TMP35:%.*]] = mul i64 [[TMP34]], 4
+; CHECK-NEXT: [[N_MOD_VF3:%.*]] = urem i64 [[TMP3]], [[TMP35]]
+; CHECK-NEXT: [[N_VEC4:%.*]] = sub i64 [[TMP3]], [[N_MOD_VF3]]
+; CHECK-NEXT: [[IND_END:%.*]] = add i64 [[TMP0]], [[N_VEC4]]
+; CHECK-NEXT: [[TMP36:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT: [[TMP37:%.*]] = mul i64 [[TMP36]], 4
+; CHECK-NEXT: [[BROADCAST_SPLATINSERT8:%.*]] = insertelement <vscale x 4 x i8> poison, i8 [[CONV]], i64 0
+; CHECK-NEXT: [[BROADCAST_SPLAT9:%.*]] = shufflevector <vscale x 4 x i8> [[BROADCAST_SPLATINSERT8]], <vscale x 4 x i8> poison, <vscale x 4 x i32> zeroinitializer
+; CHECK-NEXT: br label %[[VEC_EPILOG_VECTOR_BODY:.*]]
+; CHECK: [[VEC_EPILOG_VECTOR_BODY]]:
+; CHECK-NEXT: [[INDEX6:%.*]] = phi i64 [ [[VEC_EPILOG_RESUME_VAL]], %[[VEC_EPILOG_PH]] ], [ [[INDEX_NEXT11:%.*]], %[[VEC_EPILOG_VECTOR_BODY]] ]
+; CHECK-NEXT: [[OFFSET_IDX7:%.*]] = add i64 [[TMP0]], [[INDEX6]]
+; CHECK-NEXT: [[TMP38:%.*]] = add i64 [[OFFSET_IDX7]], 0
+; CHECK-NEXT: [[TMP39:%.*]] = getelementptr inbounds [100 x i8], ptr [[V]], i64 0, i64 [[TMP38]]
+; CHECK-NEXT: [[TMP40:%.*]] = getelementptr inbounds i8, ptr [[TMP39]], i32 0
+; CHECK-NEXT: [[WIDE_LOAD7:%.*]] = load <vscale x 4 x i8>, ptr [[TMP40]], align 1
+; CHECK-NEXT: [[TMP41:%.*]] = add <vscale x 4 x i8> [[WIDE_LOAD7]], [[BROADCAST_SPLAT9]]
+; CHECK-NEXT: store <vscale x 4 x i8> [[TMP41]], ptr [[TMP40]], align 1
+; CHECK-NEXT: [[INDEX_NEXT11]] = add nuw i64 [[INDEX6]], [[TMP37]]
+; CHECK-NEXT: [[TMP42:%.*]] = icmp eq i64 [[INDEX_NEXT11]], [[N_VEC4]]
+; CHECK-NEXT: br i1 [[TMP42]], label %[[VEC_EPILOG_MIDDLE_BLOCK:.*]], label %[[VEC_EPILOG_VECTOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK: [[VEC_EPILOG_MIDDLE_BLOCK]]:
+; CHECK-NEXT: [[CMP_N12:%.*]] = icmp eq i64 [[TMP3]], [[N_VEC4]]
+; CHECK-NEXT: br i1 [[CMP_N12]], label %[[WHILE_END_LOOPEXIT]], label %[[VEC_EPILOG_SCALAR_PH]]
+; CHECK: [[VEC_EPILOG_SCALAR_PH]]:
+; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[IND_END]], %[[VEC_EPILOG_MIDDLE_BLOCK]] ], [ [[IND_END5]], %[[VEC_EPILOG_ITER_CHECK]] ], [ [[TMP0]], %[[VECTOR_SCEVCHECK]] ], [ [[TMP0]], %[[ITER_CHECK]] ]
+; CHECK-NEXT: br label %[[WHILE_BODY:.*]]
+; CHECK: [[WHILE_BODY]]:
+; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[VEC_EPILOG_SCALAR_PH]] ], [ [[INDVARS_IV_NEXT:%.*]], %[[WHILE_BODY]] ]
+; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
+; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds nuw [100 x i8], ptr [[V]], i64 0, i64 [[INDVARS_IV]]
+; CHECK-NEXT: [[TMP43:%.*]] = load i8, ptr [[ARRAYIDX]], align 1
+; CHECK-NEXT: [[ADD:%.*]] = add i8 [[TMP43]], [[CONV]]
+; CHECK-NEXT: store i8 [[ADD]], ptr [[ARRAYIDX]], align 1
+; CHECK-NEXT: [[TMP44:%.*]] = and i64 [[INDVARS_IV_NEXT]], 4294967295
+; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64 [[TMP44]], 19
+; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label %[[WHILE_END_LOOPEXIT]], label %[[WHILE_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK: [[WHILE_END_LOOPEXIT]]:
+; CHECK-NEXT: br label %[[WHILE_END]]
+; CHECK: [[WHILE_END]]:
+; CHECK-NEXT: ret void
+;
+entry:
+ %p.promoted = load i32, ptr %p, align 4
+ %cmp7 = icmp ult i32 %p.promoted, 19
+ br i1 %cmp7, label %while.preheader, label %while.end
+
+while.preheader:
+ %conv = trunc i16 %val to i8
+ %v = getelementptr inbounds nuw i8, ptr %p, i64 4
+ %0 = zext nneg i32 %p.promoted to i64
+ br label %while.body
+
+while.body:
+ %indvars.iv = phi i64 [ %0, %while.preheader ], [ %indvars.iv.next, %while.body ]
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+ %arrayidx = getelementptr inbounds nuw [100 x i8], ptr %v, i64 0, i64 %indvars.iv
+ %1 = load i8, ptr %arrayidx, align 1
+ %add = add i8 %1, %conv
+ store i8 %add, ptr %arrayidx, align 1
+ %2 = and i64 %indvars.iv.next, 4294967295
+ %exitcond.not = icmp eq i64 %2, 19
+ br i1 %exitcond.not, label %while.end, label %while.body
+
+while.end:
+ ret void
+}
+
+define void @trip_count_too_small(ptr nocapture noundef %p, i16 noundef %val) {
+; CHECK-LABEL: define void @trip_count_too_small(
+; CHECK-SAME: ptr nocapture noundef [[P:%.*]], i16 noundef [[VAL:%.*]]) #[[ATTR0]] {
+; CHECK-NEXT: [[ENTRY:.*:]]
+; CHECK-NEXT: [[P_PROMOTED:%.*]] = load i32, ptr [[P]], align 4
+; CHECK-NEXT: [[CMP7:%.*]] = icmp ult i32 [[P_PROMOTED]], 3
+; CHECK-NEXT: br i1 [[CMP7]], label %[[WHILE_PREHEADER:.*]], label %[[WHILE_END:.*]]
+; CHECK: [[WHILE_PREHEADER]]:
+; CHECK-NEXT: [[CONV:%.*]] = trunc i16 [[VAL]] to i8
+; CHECK-NEXT: [[V:%.*]] = getelementptr inbounds nuw i8, ptr [[P]], i64 4
+; CHECK-NEXT: [[TMP0:%.*]] = zext nneg i32 [[P_PROMOTED]] to i64
+; CHECK-NEXT: br label %[[WHILE_BODY:.*]]
+; CHECK: [[WHILE_BODY]]:
+; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[TMP0]], %[[WHILE_PREHEADER]] ], [ [[INDVARS_IV_NEXT:%.*]], %[[WHILE_BODY]] ]
+; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
+; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds nuw [100 x i8], ptr [[V]], i64 0, i64 [[INDVARS_IV]]
+; CHECK-NEXT: [[TMP43:%.*]] = load i8, ptr [[ARRAYIDX]], align 1
+; CHECK-NEXT: [[ADD:%.*]] = add i8 [[TMP43]], [[CONV]]
+; CHECK-NEXT: store i8 [[ADD]], ptr [[ARRAYIDX]], align 1
+; CHECK-NEXT: [[TMP44:%.*]] = and i64 [[INDVARS_IV_NEXT]], 4294967295
+; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64 [[TMP44]], 3
+; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label %[[WHILE_END_LOOPEXIT:.*]], label %[[WHILE_BODY]]
+; CHECK: [[WHILE_END_LOOPEXIT]]:
+; CHECK-NEXT: br label %[[WHILE_END]]
+; CHECK: [[WHILE_END]]:
+; CHECK-NEXT: ret void
+;
+entry:
+ %p.promoted = load i32, ptr %p, align 4
+ %cmp7 = icmp ult i32 %p.promoted, 3
+ br i1 %cmp7, label %while.preheader, label %while.end
+
+while.preheader:
+ %conv = trunc i16 %val to i8
+ %v = getelementptr inbounds nuw i8, ptr %p, i64 4
+ %0 = zext nneg i32 %p.promoted to i64
+ br label %while.body
+
+while.body:
+ %indvars.iv = phi i64 [ %0, %while.preheader ], [ %indvars.iv.next, %while.body ]
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+ %arrayidx = getelementptr inbounds nuw [100 x i8], ptr %v, i64 0, i64 %indvars.iv
+ %1 = load i8, ptr %arrayidx, align 1
+ %add = add i8 %1, %conv
+ store i8 %add, ptr %arrayidx, align 1
+ %2 = and i64 %indvars.iv.next, 4294967295
+ %exitcond.not = icmp eq i64 %2, 3
+ br i1 %exitcond.not, label %while.end, label %while.body
+
+while.end:
+ ret void
+}
+
+define void @too_many_runtime_checks(ptr nocapture noundef %p, ptr nocapture noundef %p1, ptr nocapture noundef readonly %p2, ptr nocapture noundef readonly %p3, i16 noundef %val) {
+; CHECK-LABEL: define void @too_many_runtime_checks(
+; CHECK-SAME: ptr nocapture noundef [[P:%.*]], ptr nocapture noundef [[P1:%.*]], ptr nocapture noundef readonly [[P2:%.*]], ptr nocapture noundef readonly [[P3:%.*]], i16 noundef [[VAL:%.*]]) #[[ATTR0]] {
+; CHECK-NEXT: [[ENTRY:.*:]]
+; CHECK-NEXT: [[TMP0:%.*]] = load i32, ptr [[P]], align 4
+; CHECK-NEXT: [[CMP20:%.*]] = icmp ult i32 [[TMP0]], 16
+; CHECK-NEXT: br i1 [[CMP20]], label %[[WHILE_PREHEADER:.*]], label %[[WHILE_END:.*]]
+; CHECK: [[WHILE_PREHEADER]]:
+; CHECK-NEXT: [[CONV8:%.*]] = trunc i16 [[VAL]] to i8
+; CHECK-NEXT: [[V:%.*]] = getelementptr inbounds nuw i8, ptr [[P]], i64 4
+; CHECK-NEXT: [[TMP1:%.*]] = zext nneg i32 [[TMP0]] to i64
+; CHECK-NEXT: br label %[[WHILE_BODY:.*]]
+; CHECK: [[WHILE_BODY]]:
+; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[TMP1]], %[[WHILE_PREHEADER]] ], [ [[INDVARS_IV_NEXT:%.*]], %[[WHILE_BODY]] ]
+; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds nuw i8, ptr [[P2]], i64 [[INDVARS_IV]]
+; CHECK-NEXT: [[TMP60:%.*]] = load i8, ptr [[ARRAYIDX]], align 1
+; CHECK-NEXT: [[ARRAYIDX2:%.*]] = getelementptr inbounds nuw i8, ptr [[P3]], i64 [[INDVARS_IV]]
+; CHECK-NEXT: [[TMP61:%.*]] = load i8, ptr [[ARRAYIDX2]], align 1
+; CHECK-NEXT: [[MUL:%.*]] = mul i8 [[TMP61]], [[TMP60]]
+; CHECK-NEXT: [[ARRAYIDX5:%.*]] = getelementptr inbounds nuw i8, ptr [[P1]], i64 [[INDVARS_IV]]
+; CHECK-NEXT: [[TMP62:%.*]] = load i8, ptr [[ARRAYIDX5]], align 1
+; CHECK-NEXT: [[ADD:%.*]] = add i8 [[MUL]], [[TMP62]]
+; CHECK-NEXT: store i8 [[ADD]], ptr [[ARRAYIDX5]], align 1
+; CHECK-NEXT: [[ARRAYIDX10:%.*]] = getelementptr inbounds nuw [100 x i8], ptr [[V]], i64 0, i64 [[INDVARS_IV]]
+; CHECK-NEXT: [[TMP63:%.*]] = load i8, ptr [[ARRAYIDX10]], align 1
+; CHECK-NEXT: [[ADD12:%.*]] = add i8 [[TMP63]], [[CONV8]]
+; CHECK-NEXT: store i8 [[ADD12]], ptr [[ARRAYIDX10]], align 1
+; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
+; CHECK-NEXT: [[TMP64:%.*]] = and i64 [[INDVARS_IV_NEXT]], 4294967295
+; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64 [[TMP64]], 16
+; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label %[[WHILE_END_LOOPEXIT:.*]], label %[[WHILE_BODY]]
+; CHECK: [[WHILE_END_LOOPEXIT]]:
+; CHECK-NEXT: br label %[[WHILE_END]]
+; CHECK: [[WHILE_END]]:
+; CHECK-NEXT: ret void
+;
+entry:
+ %0 = load i32, ptr %p, align 4
+ %cmp20 = icmp ult i32 %0, 16
+ br i1 %cmp20, label %while.preheader, label %while.end
+
+while.preheader:
+ %conv8 = trunc i16 %val to i8
+ %v = getelementptr inbounds nuw i8, ptr %p, i64 4
+ %1 = zext nneg i32 %0 to i64
+ br label %while.body
+
+while.body:
+ %indvars.iv = phi i64 [ %1, %while.preheader ], [ %indvars.iv.next, %while.body ]
+ %arrayidx = getelementptr inbounds nuw i8, ptr %p2, i64 %indvars.iv
+ %2 = load i8, ptr %arrayidx, align 1
+ %arrayidx2 = getelementptr inbounds nuw i8, ptr %p3, i64 %indvars.iv
+ %3 = load i8, ptr %arrayidx2, align 1
+ %mul = mul i8 %3, %2
+ %arrayidx5 = getelementptr inbounds nuw i8, ptr %p1, i64 %indvars.iv
+ %4 = load i8, ptr %arrayidx5, align 1
+ %add = add i8 %mul, %4
+ store i8 %add, ptr %arrayidx5, align 1
+ %arrayidx10 = getelementptr inbounds nuw [100 x i8], ptr %v, i64 0, i64 %indvars.iv
+ %5 = load i8, ptr %arrayidx10, align 1
+ %add12 = add i8 %5, %conv8
+ store i8 %add12, ptr %arrayidx10, align 1
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+ %6 = and i64 %indvars.iv.next, 4294967295
+ %exitcond.not = icmp eq i64 %6, 16
+ br i1 %exitcond.not, label %while.end, label %while.body
+
+while.end:
+ ret void
+}
+
+define void @overflow_indvar_known_false(ptr nocapture noundef %p, i16 noundef %val) vscale_range(1,16) {
+; CHECK-LABEL: define void @overflow_indvar_known_false(
+; CHECK-SAME: ptr nocapture noundef [[P:%.*]], i16 noundef [[VAL:%.*]]) #[[ATTR1:[0-9]+]] {
+; CHECK-NEXT: [[ENTRY:.*:]]
+; CHECK-NEXT: [[P_PROMOTED:%.*]] = load i32, ptr [[P]], align 4
+; CHECK-NEXT: [[CMP7:%.*]] = icmp ult i32 [[P_PROMOTED]], 1027
+; CHECK-NEXT: br i1 [[CMP7]], label %[[WHILE_PREHEADER:.*]], label %[[WHILE_END:.*]]
+; CHECK: [[WHILE_PREHEADER]]:
+; CHECK-NEXT: [[CONV:%.*]] = trunc i16 [[VAL]] to i8
+; CHECK-NEXT: [[V:%.*]] = getelementptr inbounds nuw i8, ptr [[P]], i64 4
+; CHECK-NEXT: [[TMP0:%.*]] = zext nneg i32 [[P_PROMOTED]] to i64
+; CHECK-NEXT: [[TMP19:%.*]] = add i32 [[P_PROMOTED]], 1
+; CHECK-NEXT: [[TMP20:%.*]] = zext i32 [[TMP19...
[truncated]
``````````
</details>
https://github.com/llvm/llvm-project/pull/109928
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