[llvm] [ConstraintElimination] Use SCEV ranges information for Loop counter (PR #91457)
via llvm-commits
llvm-commits at lists.llvm.org
Wed May 8 03:39:14 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms
@llvm/pr-subscribers-llvm-analysis
Author: None (v01dXYZ)
<details>
<summary>Changes</summary>
Fixes https://github.com/llvm/llvm-project/issues/90417
The modifications allow to use SCEV ranges for the loop counter to allow simplifications that doesn't depend on the branch taken.
As SCEV could create large numbers that would very likely trigger an overflow with `ConstraintSystem`, `ConstraintSystem` was modified to skip the constraint when overflow occurs.
---
Patch is 25.16 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/91457.diff
12 Files Affected:
- (modified) llvm/include/llvm/Analysis/ConstraintSystem.h (+9-1)
- (modified) llvm/lib/Analysis/ConstraintSystem.cpp (+32-29)
- (modified) llvm/lib/Transforms/Scalar/ConstraintElimination.cpp (+39-5)
- (modified) llvm/test/Transforms/ConstraintElimination/constraint-overflow.ll (+1-2)
- (modified) llvm/test/Transforms/ConstraintElimination/loops-bottom-tested-base.ll (+5-10)
- (modified) llvm/test/Transforms/ConstraintElimination/loops-header-tested-base.ll (+13-24)
- (modified) llvm/test/Transforms/ConstraintElimination/loops.ll (+4-7)
- (modified) llvm/test/Transforms/ConstraintElimination/monotonic-int-phis-decrement.ll (+1-2)
- (modified) llvm/test/Transforms/ConstraintElimination/monotonic-int-phis-wrapping.ll (+3-6)
- (added) llvm/test/Transforms/ConstraintElimination/scev-phis-range-facts.ll (+83)
- (modified) llvm/test/Transforms/ConstraintElimination/transfer-signed-facts-to-unsigned-is-known-non-negative.ll (+3-6)
- (modified) llvm/test/Transforms/ConstraintElimination/transfer-unsigned-facts-to-signed-is-known-non-negative.ll (+3-4)
``````````diff
diff --git a/llvm/include/llvm/Analysis/ConstraintSystem.h b/llvm/include/llvm/Analysis/ConstraintSystem.h
index 7b02b618f7cb4..d8698a6f64347 100644
--- a/llvm/include/llvm/Analysis/ConstraintSystem.h
+++ b/llvm/include/llvm/Analysis/ConstraintSystem.h
@@ -43,6 +43,8 @@ class ConstraintSystem {
return 0;
}
+ // WARNING: it represents rather the maximum number of coefficients in the constraints
+ // which is actually the number of variables PLUS one (for the constant part).
size_t NumVariables = 0;
/// Current linear constraints in the system.
@@ -54,7 +56,13 @@ class ConstraintSystem {
/// constraint system.
DenseMap<Value *, unsigned> Value2Index;
- // Eliminate constraints from the system using Fourier–Motzkin elimination.
+ // Eliminate the last variable from the system using Fourier–Motzkin
+ // elimination, while possibly relaxing it if it is beyond
+ // acceptable means (too many created constraints, overflow when
+ // computing the coefficients)
+ //
+ // return true if the updated system is equivalent, otherwise return
+ // false if it is relaxed.
bool eliminateUsingFM();
/// Returns true if there may be a solution for the constraints in the system.
diff --git a/llvm/lib/Analysis/ConstraintSystem.cpp b/llvm/lib/Analysis/ConstraintSystem.cpp
index 1a9c7c21e9ced..9dc6d25d11492 100644
--- a/llvm/lib/Analysis/ConstraintSystem.cpp
+++ b/llvm/lib/Analysis/ConstraintSystem.cpp
@@ -47,23 +47,24 @@ bool ConstraintSystem::eliminateUsingFM() {
}
}
+ // Track if an overflow occurred when computing coefficents
+ bool Overflow = false;
+
// Process rows where the variable is != 0.
unsigned NumRemainingConstraints = RemainingRows.size();
for (unsigned R1 = 0; R1 < NumRemainingConstraints; R1++) {
// FIXME do not use copy
for (unsigned R2 = R1 + 1; R2 < NumRemainingConstraints; R2++) {
- if (R1 == R2)
- continue;
-
int64_t UpperLast = getLastCoefficient(RemainingRows[R2], LastIdx);
int64_t LowerLast = getLastCoefficient(RemainingRows[R1], LastIdx);
assert(
UpperLast != 0 && LowerLast != 0 &&
"RemainingRows should only contain rows where the variable is != 0");
+ // ensure signs are different then swap if necessary to only
+ // deal with UpperLast > 0
if ((LowerLast < 0 && UpperLast < 0) || (LowerLast > 0 && UpperLast > 0))
continue;
-
unsigned LowerR = R1;
unsigned UpperR = R2;
if (UpperLast < 0) {
@@ -71,43 +72,42 @@ bool ConstraintSystem::eliminateUsingFM() {
std::swap(LowerLast, UpperLast);
}
+ // The following loop does the element-wise operation on sparse
+ // vectors:
+ //
+ // NR = - UpperRow * LowerLast + LowerRow * UpperLast
SmallVector<Entry, 8> NR;
unsigned IdxUpper = 0;
unsigned IdxLower = 0;
auto &LowerRow = RemainingRows[LowerR];
auto &UpperRow = RemainingRows[UpperR];
- while (true) {
- if (IdxUpper >= UpperRow.size() || IdxLower >= LowerRow.size())
- break;
+
+ while (IdxUpper < UpperRow.size() && IdxLower < LowerRow.size()) {
int64_t M1, M2, N;
int64_t UpperV = 0;
int64_t LowerV = 0;
- uint16_t CurrentId = std::numeric_limits<uint16_t>::max();
- if (IdxUpper < UpperRow.size()) {
- CurrentId = std::min(UpperRow[IdxUpper].Id, CurrentId);
- }
- if (IdxLower < LowerRow.size()) {
- CurrentId = std::min(LowerRow[IdxLower].Id, CurrentId);
- }
+ uint16_t CurrentId =
+ std::min(UpperRow[IdxUpper].Id, LowerRow[IdxLower].Id);
- if (IdxUpper < UpperRow.size() && UpperRow[IdxUpper].Id == CurrentId) {
+ if (UpperRow[IdxUpper].Id == CurrentId) {
UpperV = UpperRow[IdxUpper].Coefficient;
- IdxUpper++;
+ IdxUpper += 1;
}
-
- if (MulOverflow(UpperV, -1 * LowerLast, M1))
- return false;
- if (IdxLower < LowerRow.size() && LowerRow[IdxLower].Id == CurrentId) {
+ if (LowerRow[IdxLower].Id == CurrentId) {
LowerV = LowerRow[IdxLower].Coefficient;
- IdxLower++;
+ IdxLower += 1;
+ }
+
+ if (MulOverflow(UpperV, -1 * LowerLast, M1) ||
+ MulOverflow(LowerV, UpperLast, M2) || AddOverflow(M1, M2, N)) {
+ Overflow = true;
+ continue;
}
- if (MulOverflow(LowerV, UpperLast, M2))
- return false;
- if (AddOverflow(M1, M2, N))
- return false;
+ // useless to add a 0 to a sparse vector
if (N == 0)
continue;
+
NR.emplace_back(N, CurrentId);
}
if (NR.empty())
@@ -120,13 +120,16 @@ bool ConstraintSystem::eliminateUsingFM() {
}
NumVariables -= 1;
- return true;
+ return !Overflow;
}
bool ConstraintSystem::mayHaveSolutionImpl() {
- while (!Constraints.empty() && NumVariables > 1) {
- if (!eliminateUsingFM())
- return true;
+ while (!Constraints.empty() && Constraints.size() <= 500 && NumVariables > 1) {
+ if(!eliminateUsingFM()) {
+ LLVM_DEBUG(
+ dbgs()
+ << "Some new constraints has been ignored during elimination.\n");
+ };
}
if (Constraints.empty() || NumVariables > 1)
diff --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index 7e48c28176bd1..e4f2feb1b28bf 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -916,6 +916,45 @@ void State::addInfoForInductions(BasicBlock &BB) {
!SE.isSCEVable(PN->getType()))
return;
+ auto *AR = dyn_cast_or_null<SCEVAddRecExpr>(SE.getSCEV(PN));
+ BasicBlock *LoopPred = L->getLoopPredecessor();
+ if (!AR || AR->getLoop() != L || !LoopPred)
+ return;
+
+ // If SCEV provides relevant range information, we push those facts
+ // to the worklist relatively to the header node itself (and not its
+ // successor).
+ auto UnsignedRange = SE.getUnsignedRange(AR);
+ auto SignedRange = SE.getSignedRange(AR);
+ DomTreeNode *DTNHeader = DT.getNode(&BB);
+
+ // The range can wrap thus we take Min/Max instead of Lower/Upper
+ auto UnsignedMin = UnsignedRange.getUnsignedMin();
+ auto UnsignedMax = UnsignedRange.getUnsignedMax();
+ if (!UnsignedMax.isMaxValue()) {
+ WorkList.push_back(FactOrCheck::getConditionFact(
+ DTNHeader, CmpInst::ICMP_ULE, PN,
+ Constant::getIntegerValue(PN->getType(), UnsignedMax)));
+ }
+ if (!UnsignedMin.isMinValue()) {
+ WorkList.push_back(FactOrCheck::getConditionFact(
+ DTNHeader, CmpInst::ICMP_UGE, PN,
+ Constant::getIntegerValue(PN->getType(), UnsignedMin)));
+ }
+
+ auto SignedMin = SignedRange.getSignedMin();
+ auto SignedMax = SignedRange.getSignedMax();
+ if (!SignedMax.isMaxSignedValue()) {
+ WorkList.push_back(FactOrCheck::getConditionFact(
+ DTNHeader, CmpInst::ICMP_SLE, PN,
+ Constant::getIntegerValue(PN->getType(), SignedMax)));
+ }
+ if (!SignedMin.isMinSignedValue()) {
+ WorkList.push_back(FactOrCheck::getConditionFact(
+ DTNHeader, CmpInst::ICMP_SGE, PN,
+ Constant::getIntegerValue(PN->getType(), SignedMin)));
+ }
+
BasicBlock *InLoopSucc = nullptr;
if (Pred == CmpInst::ICMP_NE)
InLoopSucc = cast<BranchInst>(BB.getTerminator())->getSuccessor(0);
@@ -927,11 +966,6 @@ void State::addInfoForInductions(BasicBlock &BB) {
if (!L->contains(InLoopSucc) || !L->isLoopExiting(&BB) || InLoopSucc == &BB)
return;
- auto *AR = dyn_cast_or_null<SCEVAddRecExpr>(SE.getSCEV(PN));
- BasicBlock *LoopPred = L->getLoopPredecessor();
- if (!AR || AR->getLoop() != L || !LoopPred)
- return;
-
const SCEV *StartSCEV = AR->getStart();
Value *StartValue = nullptr;
if (auto *C = dyn_cast<SCEVConstant>(StartSCEV)) {
diff --git a/llvm/test/Transforms/ConstraintElimination/constraint-overflow.ll b/llvm/test/Transforms/ConstraintElimination/constraint-overflow.ll
index 88f87f4afab28..efb89fd0512d9 100644
--- a/llvm/test/Transforms/ConstraintElimination/constraint-overflow.ll
+++ b/llvm/test/Transforms/ConstraintElimination/constraint-overflow.ll
@@ -13,8 +13,7 @@ define i32 @f(i64 %a3, i64 %numElements) {
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i64 [[A1]], [[A3]]
; CHECK-NEXT: br i1 [[CMP]], label [[IF_END_I:%.*]], label [[ABORT:%.*]]
; CHECK: if.end.i:
-; CHECK-NEXT: [[CMP2_NOT_I:%.*]] = icmp ult i64 [[A1]], [[A3]]
-; CHECK-NEXT: br i1 [[CMP2_NOT_I]], label [[ABORT]], label [[EXIT:%.*]]
+; CHECK-NEXT: br i1 false, label [[ABORT]], label [[EXIT:%.*]]
; CHECK: abort:
; CHECK-NEXT: ret i32 -1
; CHECK: exit:
diff --git a/llvm/test/Transforms/ConstraintElimination/loops-bottom-tested-base.ll b/llvm/test/Transforms/ConstraintElimination/loops-bottom-tested-base.ll
index 3dbea9496da8d..72a998e71ff87 100644
--- a/llvm/test/Transforms/ConstraintElimination/loops-bottom-tested-base.ll
+++ b/llvm/test/Transforms/ConstraintElimination/loops-bottom-tested-base.ll
@@ -11,10 +11,8 @@ define void @loop_iv_cond_variable_bound(i32 %n) {
; CHECK-NEXT: [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
; CHECK-NEXT: [[T_1:%.*]] = icmp ule i32 [[IV]], [[N:%.*]]
; CHECK-NEXT: call void @use(i1 [[T_1]])
-; CHECK-NEXT: [[T_2:%.*]] = icmp sge i32 [[IV]], 0
-; CHECK-NEXT: call void @use(i1 [[T_2]])
-; CHECK-NEXT: [[T_3:%.*]] = icmp sge i32 [[IV]], -1
-; CHECK-NEXT: call void @use(i1 [[T_3]])
+; CHECK-NEXT: call void @use(i1 true)
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[C_1:%.*]] = icmp ult i32 [[IV]], [[N]]
; CHECK-NEXT: call void @use(i1 [[C_1]])
; CHECK-NEXT: [[C_2:%.*]] = icmp ugt i32 [[IV]], 1
@@ -56,12 +54,9 @@ define void @loop_iv_cond_constant_bound() {
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
-; CHECK-NEXT: [[T_1:%.*]] = icmp ule i32 [[IV]], 2
-; CHECK-NEXT: call void @use(i1 [[T_1]])
-; CHECK-NEXT: [[T_2:%.*]] = icmp sge i32 [[IV]], 0
-; CHECK-NEXT: call void @use(i1 [[T_2]])
-; CHECK-NEXT: [[T_3:%.*]] = icmp sge i32 [[IV]], -1
-; CHECK-NEXT: call void @use(i1 [[T_3]])
+; CHECK-NEXT: call void @use(i1 true)
+; CHECK-NEXT: call void @use(i1 true)
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[C_1:%.*]] = icmp ult i32 [[IV]], 2
; CHECK-NEXT: call void @use(i1 [[C_1]])
; CHECK-NEXT: [[C_2:%.*]] = icmp ugt i32 [[IV]], 1
diff --git a/llvm/test/Transforms/ConstraintElimination/loops-header-tested-base.ll b/llvm/test/Transforms/ConstraintElimination/loops-header-tested-base.ll
index 7b928a030614b..61b3411a8cded 100644
--- a/llvm/test/Transforms/ConstraintElimination/loops-header-tested-base.ll
+++ b/llvm/test/Transforms/ConstraintElimination/loops-header-tested-base.ll
@@ -14,15 +14,11 @@ define void @loop_phi_pos_start_value(i32 %y, i1 %c, i32 %n) {
; CHECK: loop.latch:
; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: call void @use(i1 false)
-; CHECK-NEXT: [[T_2:%.*]] = icmp sge i32 [[X]], 10
-; CHECK-NEXT: call void @use(i1 [[T_2]])
-; CHECK-NEXT: [[C_2:%.*]] = icmp sle i32 [[X]], 9
-; CHECK-NEXT: call void @use(i1 [[C_2]])
-; CHECK-NEXT: [[C_3:%.*]] = icmp sgt i32 [[X]], 9
-; CHECK-NEXT: call void @use(i1 [[C_3]])
; CHECK-NEXT: call void @use(i1 true)
-; CHECK-NEXT: [[C_5:%.*]] = icmp sge i32 [[X]], 9
-; CHECK-NEXT: call void @use(i1 [[C_5]])
+; CHECK-NEXT: call void @use(i1 false)
+; CHECK-NEXT: call void @use(i1 true)
+; CHECK-NEXT: call void @use(i1 true)
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[X_NEXT]] = add nsw i32 [[X]], 1
; CHECK-NEXT: br label [[LOOP_HEADER]]
; CHECK: exit:
@@ -75,8 +71,7 @@ define void @loop_phi_neg_start_value(i32 %y, i1 %c, i32 %n) {
; CHECK: loop.latch:
; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: call void @use(i1 false)
-; CHECK-NEXT: [[T_2:%.*]] = icmp sge i32 [[X]], -10
-; CHECK-NEXT: call void @use(i1 [[T_2]])
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[C_2:%.*]] = icmp sle i32 [[X]], 9
; CHECK-NEXT: call void @use(i1 [[C_2]])
; CHECK-NEXT: [[C_3:%.*]] = icmp sgt i32 [[X]], 9
@@ -248,12 +243,11 @@ define void @loop_latch_not_executed_constant_bound(i32 %y, i1 %c) {
; CHECK-NEXT: br i1 [[C:%.*]], label [[LOOP_HEADER:%.*]], label [[EXIT:%.*]]
; CHECK: loop.header:
; CHECK-NEXT: [[X:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[X_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
-; CHECK-NEXT: [[C_1:%.*]] = icmp ugt i32 [[X]], 10
-; CHECK-NEXT: br i1 [[C_1]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK-NEXT: br i1 false, label [[LOOP_LATCH]], label [[EXIT]]
; CHECK: loop.latch:
-; CHECK-NEXT: call void @use(i1 false)
; CHECK-NEXT: call void @use(i1 true)
-; CHECK-NEXT: call void @use(i1 false)
+; CHECK-NEXT: call void @use(i1 true)
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[X_NEXT]] = add i32 [[X]], 1
; CHECK-NEXT: br label [[LOOP_HEADER]]
@@ -299,10 +293,8 @@ define void @loop_iv_cond_variable_bound(i32 %n) {
; CHECK-NEXT: [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
; CHECK-NEXT: [[T_1:%.*]] = icmp ule i32 [[IV]], [[N:%.*]]
; CHECK-NEXT: call void @use(i1 [[T_1]])
-; CHECK-NEXT: [[T_2:%.*]] = icmp sge i32 [[IV]], 0
-; CHECK-NEXT: call void @use(i1 [[T_2]])
-; CHECK-NEXT: [[T_3:%.*]] = icmp sge i32 [[IV]], -1
-; CHECK-NEXT: call void @use(i1 [[T_3]])
+; CHECK-NEXT: call void @use(i1 true)
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[C_1:%.*]] = icmp ult i32 [[IV]], [[N]]
; CHECK-NEXT: call void @use(i1 [[C_1]])
; CHECK-NEXT: [[C_2:%.*]] = icmp ugt i32 [[IV]], 1
@@ -362,12 +354,9 @@ define void @loop_iv_cond_constant_bound() {
; CHECK-NEXT: br label [[LOOP_HEADER:%.*]]
; CHECK: loop.header:
; CHECK-NEXT: [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
-; CHECK-NEXT: [[T_1:%.*]] = icmp ule i32 [[IV]], 2
-; CHECK-NEXT: call void @use(i1 [[T_1]])
-; CHECK-NEXT: [[T_2:%.*]] = icmp sge i32 [[IV]], 0
-; CHECK-NEXT: call void @use(i1 [[T_2]])
-; CHECK-NEXT: [[T_3:%.*]] = icmp sge i32 [[IV]], -1
-; CHECK-NEXT: call void @use(i1 [[T_3]])
+; CHECK-NEXT: call void @use(i1 true)
+; CHECK-NEXT: call void @use(i1 true)
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[C_1:%.*]] = icmp ult i32 [[IV]], 2
; CHECK-NEXT: call void @use(i1 [[C_1]])
; CHECK-NEXT: [[C_2:%.*]] = icmp ugt i32 [[IV]], 1
diff --git a/llvm/test/Transforms/ConstraintElimination/loops.ll b/llvm/test/Transforms/ConstraintElimination/loops.ll
index 25d4ac436ce8c..8753fff4aac7e 100644
--- a/llvm/test/Transforms/ConstraintElimination/loops.ll
+++ b/llvm/test/Transforms/ConstraintElimination/loops.ll
@@ -107,15 +107,12 @@ define i32 @loop_header_dom_successors_flipped(i32 %y, i1 %c) {
; CHECK-NEXT: br i1 [[C:%.*]], label [[LOOP_HEADER:%.*]], label [[EXIT:%.*]]
; CHECK: loop.header:
; CHECK-NEXT: [[X:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[X_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
-; CHECK-NEXT: [[C_1:%.*]] = icmp ule i32 [[X]], 10
-; CHECK-NEXT: br i1 [[C_1]], label [[EXIT]], label [[LOOP_LATCH]]
+; CHECK-NEXT: br i1 true, label [[EXIT]], label [[LOOP_LATCH]]
; CHECK: loop.latch:
-; CHECK-NEXT: call void @use(i1 false)
; CHECK-NEXT: call void @use(i1 true)
-; CHECK-NEXT: [[C_2:%.*]] = icmp ugt i32 [[X]], 11
-; CHECK-NEXT: call void @use(i1 [[C_2]])
-; CHECK-NEXT: [[C_3:%.*]] = icmp ule i32 [[X]], 11
-; CHECK-NEXT: call void @use(i1 [[C_3]])
+; CHECK-NEXT: call void @use(i1 true)
+; CHECK-NEXT: call void @use(i1 true)
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[X_NEXT]] = add i32 [[X]], 1
; CHECK-NEXT: br label [[LOOP_HEADER]]
; CHECK: exit:
diff --git a/llvm/test/Transforms/ConstraintElimination/monotonic-int-phis-decrement.ll b/llvm/test/Transforms/ConstraintElimination/monotonic-int-phis-decrement.ll
index 155423d33a69a..a81f2059026c0 100644
--- a/llvm/test/Transforms/ConstraintElimination/monotonic-int-phis-decrement.ll
+++ b/llvm/test/Transforms/ConstraintElimination/monotonic-int-phis-decrement.ll
@@ -197,8 +197,7 @@ define void @add_rec_decreasing_2_cond_true_constant(i8 noundef %len) {
; CHECK-NEXT: [[CMP2_NOT:%.*]] = icmp eq i8 [[K_0]], 0
; CHECK-NEXT: br i1 [[CMP2_NOT]], label [[EXIT:%.*]], label [[LOOP_LATCH]]
; CHECK: loop.latch:
-; CHECK-NEXT: [[CMP_NOT_I:%.*]] = icmp ult i8 [[K_0]], 5
-; CHECK-NEXT: call void @use(i1 [[CMP_NOT_I]])
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[K_DEC]] = add i8 [[K_0]], -2
; CHECK-NEXT: br label [[LOOP_HEADER]]
; CHECK: exit:
diff --git a/llvm/test/Transforms/ConstraintElimination/monotonic-int-phis-wrapping.ll b/llvm/test/Transforms/ConstraintElimination/monotonic-int-phis-wrapping.ll
index 17aa4d54abfba..2a58220b78f00 100644
--- a/llvm/test/Transforms/ConstraintElimination/monotonic-int-phis-wrapping.ll
+++ b/llvm/test/Transforms/ConstraintElimination/monotonic-int-phis-wrapping.ll
@@ -49,8 +49,7 @@ define void @test_iv_nuw_nsw_1_uge_start(i8 %len.n, i8 %a) {
; CHECK-NEXT: br label [[LOOP_HEADER:%.*]]
; CHECK: loop.header:
; CHECK-NEXT: [[IV:%.*]] = phi i8 [ -1, [[LOOP_PH:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
-; CHECK-NEXT: [[C:%.*]] = icmp eq i8 [[IV]], 1
-; CHECK-NEXT: br i1 [[C]], label [[EXIT:%.*]], label [[FOR_BODY:%.*]]
+; CHECK-NEXT: br i1 false, label [[EXIT:%.*]], label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[C_2:%.*]] = call i1 @cond()
; CHECK-NEXT: br i1 [[C_2]], label [[LOOP_LATCH]], label [[EXIT]]
@@ -90,8 +89,7 @@ define void @test_iv_nuw_nsw_2_uge_start(i8 %len.n, i8 %a) {
; CHECK-NEXT: br label [[LOOP_HEADER:%.*]]
; CHECK: loop.header:
; CHECK-NEXT: [[IV:%.*]] = phi i8 [ [[START]], [[LOOP_PH:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
-; CHECK-NEXT: [[C:%.*]] = icmp eq i8 [[IV]], 1
-; CHECK-NEXT: br i1 [[C]], label [[EXIT:%.*]], label [[FOR_BODY:%.*]]
+; CHECK-NEXT: br i1 false, label [[EXIT:%.*]], label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[C_2:%.*]] = call i1 @cond()
; CHECK-NEXT: br i1 [[C_2]], label [[LOOP_LATCH]], label [[EXIT]]
@@ -131,8 +129,7 @@ define void @test_iv_nsw_nuw_1_ult_end(i8 %len.n, i8 %a) {
; CHECK-NEXT: br label [[LOOP_HEADER:%.*]]
; CHECK: loop.header:
; CHECK-NEXT: [[IV:%.*]] = phi i8 [ -2, [[LOOP_PH:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
-; CHECK-NEXT: [[C:%.*]] = icmp eq i8 [[IV]], 1
-; CHECK-NEXT: br i1 [[C]], label [[EXIT:%.*]], label [[FOR_BODY:%.*]]
+; CHECK-NEXT: br i1 false, label [[EXIT:%.*]], label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[C_2:%.*]] = call i1 @cond()
; CHECK-NEXT: br i1 [[C_2]], label [[LOOP_LATCH]], label [[EXIT]]
diff --git a/llvm/test/Transforms/ConstraintElimination/scev-phis-range-facts.ll b/llvm/test/Transforms/ConstraintElimination/scev-phis-range-facts.ll
new file mode 100644
index 0000000000000..0c77574add33d
--- /dev/null
+++ b/llvm/test/Transforms/ConstraintElimination/scev-phis-range-facts.ll
@@ -0,0 +1,83 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -passes=constraint-elimination -S %s | FileCheck %s
+
+define i1 @test_ult_loop_with_ult_icmp_N_at_end(ptr %s) {
+; CHECK-LABEL: define i1 @test_ult_loop_with_ult_icmp_N_at_end(
+; CHECK-SAME: ptr [[S:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[WHILE_COND:%.*]]
+; CHECK: while.cond:
+; CHECK-NEXT: [[I_0:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[ADD:%.*]], [[WHILE_BODY:%.*]] ]
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i64 [[I_0]], 1234
+; CHECK-NEXT: br i1 [[CMP]], label [[WHILE_BODY]], label [[WHILE_END:%.*]]
+; CHECK: while.body:
+; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i8, ptr [[S]], i64 [[I_0]]
+; CHECK-NEXT: [[TMP0:%.*]] = load i8, ptr [[ARRAYIDX]], align 1
+; CHECK-NEXT: [[TMP1:%.*]] = add i8 [[TMP0]], -48
+; CHECK-NEXT: [[OR_COND:%.*]] = icmp ult i8 [[TMP1]], 10
+; CHECK-NEXT: [[ADD]] = add n...
[truncated]
``````````
</details>
https://github.com/llvm/llvm-project/pull/91457
More information about the llvm-commits
mailing list