[llvm] 6022a8b - [SCEV] Drop cached ranges of AddRecs after flag update
Max Kazantsev via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 9 21:54:01 PST 2020
Author: Max Kazantsev
Date: 2020-11-10T12:37:12+07:00
New Revision: 6022a8b7e8d1796284541bbf6bad40449c785fef
URL: https://github.com/llvm/llvm-project/commit/6022a8b7e8d1796284541bbf6bad40449c785fef
DIFF: https://github.com/llvm/llvm-project/commit/6022a8b7e8d1796284541bbf6bad40449c785fef.diff
LOG: [SCEV] Drop cached ranges of AddRecs after flag update
Our range computation methods benefit from no-wrap flags. But if the ranges
were first computed before the flags were set, the cached range will be too
pessimistic.
We need to drop cached ranges whenever we sharpen AddRec's no wrap flags.
Differential Revision: https://reviews.llvm.org/D89847
Reviewed By: fhahn
Added:
Modified:
llvm/include/llvm/Analysis/ScalarEvolution.h
llvm/lib/Analysis/ScalarEvolution.cpp
llvm/test/Analysis/ScalarEvolution/srem.ll
llvm/test/Transforms/IndVarSimplify/floating-point-iv.ll
Removed:
################################################################################
diff --git a/llvm/include/llvm/Analysis/ScalarEvolution.h b/llvm/include/llvm/Analysis/ScalarEvolution.h
index e7b81a45ba90..e25708dcdc2d 100644
--- a/llvm/include/llvm/Analysis/ScalarEvolution.h
+++ b/llvm/include/llvm/Analysis/ScalarEvolution.h
@@ -1157,6 +1157,11 @@ class ScalarEvolution {
/// to be a constant.
Optional<APInt> computeConstantDifference(const SCEV *LHS, const SCEV *RHS);
+ /// Update no-wrap flags of an AddRec. This may drop the cached info about
+ /// this AddRec (such as range info) in case if new flags may potentially
+ /// sharpen it.
+ void setNoWrapFlags(SCEVAddRecExpr *AddRec, SCEV::NoWrapFlags Flags);
+
private:
/// A CallbackVH to arrange for ScalarEvolution to be notified whenever a
/// Value is deleted.
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 77fc2d47785d..b42265fadda8 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -1381,7 +1381,7 @@ static const SCEV *getPreStartForExtend(const SCEVAddRecExpr *AR, Type *Ty,
// If we know `AR` == {`PreStart`+`Step`,+,`Step`} is `WrapType` (FlagNSW
// or FlagNUW) and that `PreStart` + `Step` is `WrapType` too, then
// `PreAR` == {`PreStart`,+,`Step`} is also `WrapType`. Cache this fact.
- const_cast<SCEVAddRecExpr *>(PreAR)->setNoWrapFlags(WrapType);
+ SE->setNoWrapFlags(const_cast<SCEVAddRecExpr *>(PreAR), WrapType);
}
return PreStart;
}
@@ -1585,7 +1585,7 @@ ScalarEvolution::getZeroExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
if (!AR->hasNoUnsignedWrap()) {
auto NewFlags = proveNoWrapViaConstantRanges(AR);
- const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(NewFlags);
+ setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), NewFlags);
}
// If we have special knowledge that this addrec won't overflow,
@@ -1634,7 +1634,7 @@ ScalarEvolution::getZeroExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
SCEV::FlagAnyWrap, Depth + 1);
if (ZAdd == OperandExtendedAdd) {
// Cache knowledge of AR NUW, which is propagated to this AddRec.
- const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW);
+ setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNUW);
// Return the expression with the addrec on the outside.
return getAddRecExpr(
getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this,
@@ -1653,7 +1653,7 @@ ScalarEvolution::getZeroExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
if (ZAdd == OperandExtendedAdd) {
// Cache knowledge of AR NW, which is propagated to this AddRec.
// Negative step causes unsigned wrap, but it still can't self-wrap.
- const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW);
+ setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNW);
// Return the expression with the addrec on the outside.
return getAddRecExpr(
getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this,
@@ -1685,7 +1685,7 @@ ScalarEvolution::getZeroExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
isKnownOnEveryIteration(ICmpInst::ICMP_ULT, AR, N)) {
// Cache knowledge of AR NUW, which is propagated to this
// AddRec.
- const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW);
+ setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNUW);
// Return the expression with the addrec on the outside.
return getAddRecExpr(
getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this,
@@ -1701,7 +1701,7 @@ ScalarEvolution::getZeroExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
// Cache knowledge of AR NW, which is propagated to this
// AddRec. Negative step causes unsigned wrap, but it
// still can't self-wrap.
- const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW);
+ setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNW);
// Return the expression with the addrec on the outside.
return getAddRecExpr(
getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this,
@@ -1730,7 +1730,7 @@ ScalarEvolution::getZeroExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
}
if (proveNoWrapByVaryingStart<SCEVZeroExtendExpr>(Start, Step, L)) {
- const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW);
+ setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNUW);
return getAddRecExpr(
getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, Depth + 1),
getZeroExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags());
@@ -1929,7 +1929,7 @@ ScalarEvolution::getSignExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
if (!AR->hasNoSignedWrap()) {
auto NewFlags = proveNoWrapViaConstantRanges(AR);
- const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(NewFlags);
+ setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), NewFlags);
}
// If we have special knowledge that this addrec won't overflow,
@@ -1978,7 +1978,7 @@ ScalarEvolution::getSignExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
SCEV::FlagAnyWrap, Depth + 1);
if (SAdd == OperandExtendedAdd) {
// Cache knowledge of AR NSW, which is propagated to this AddRec.
- const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW);
+ setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNSW);
// Return the expression with the addrec on the outside.
return getAddRecExpr(
getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this,
@@ -2003,7 +2003,7 @@ ScalarEvolution::getSignExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
// Thus (AR is not NW => SAdd != OperandExtendedAdd) <=>
// (SAdd == OperandExtendedAdd => AR is NW)
- const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW);
+ setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNW);
// Return the expression with the addrec on the outside.
return getAddRecExpr(
@@ -2037,7 +2037,7 @@ ScalarEvolution::getSignExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
(isLoopBackedgeGuardedByCond(L, Pred, AR, OverflowLimit) ||
isKnownOnEveryIteration(Pred, AR, OverflowLimit))) {
// Cache knowledge of AR NSW, then propagate NSW to the wide AddRec.
- const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW);
+ setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNSW);
return getAddRecExpr(
getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1),
getSignExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags());
@@ -2062,7 +2062,7 @@ ScalarEvolution::getSignExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
}
if (proveNoWrapByVaryingStart<SCEVSignExtendExpr>(Start, Step, L)) {
- const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW);
+ setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNSW);
return getAddRecExpr(
getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1),
getSignExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags());
@@ -2732,7 +2732,7 @@ ScalarEvolution::getOrCreateAddRecExpr(ArrayRef<const SCEV *> Ops,
UniqueSCEVs.InsertNode(S, IP);
addToLoopUseLists(S);
}
- S->setNoWrapFlags(Flags);
+ setNoWrapFlags(S, Flags);
return S;
}
@@ -5514,6 +5514,15 @@ static Optional<ConstantRange> GetRangeFromMetadata(Value *V) {
return None;
}
+void ScalarEvolution::setNoWrapFlags(SCEVAddRecExpr *AddRec,
+ SCEV::NoWrapFlags Flags) {
+ if (AddRec->getNoWrapFlags(Flags) != Flags) {
+ AddRec->setNoWrapFlags(Flags);
+ UnsignedRanges.erase(AddRec);
+ SignedRanges.erase(AddRec);
+ }
+}
+
/// Determine the range for a particular SCEV. If SignHint is
/// HINT_RANGE_UNSIGNED (resp. HINT_RANGE_SIGNED) then getRange prefers ranges
/// with a "cleaner" unsigned (resp. signed) representation.
diff --git a/llvm/test/Analysis/ScalarEvolution/srem.ll b/llvm/test/Analysis/ScalarEvolution/srem.ll
index 76e0d4a5ec5b..197437b51ca1 100644
--- a/llvm/test/Analysis/ScalarEvolution/srem.ll
+++ b/llvm/test/Analysis/ScalarEvolution/srem.ll
@@ -29,7 +29,7 @@ define dso_local void @_Z4loopi(i32 %width) local_unnamed_addr #0 {
; CHECK-NEXT: %add = add nsw i32 %2, %call
; CHECK-NEXT: --> (%2 + %call) U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
; CHECK-NEXT: %inc = add nsw i32 %i.0, 1
-; CHECK-NEXT: --> {1,+,1}<nuw><%for.cond> U: full-set S: full-set Exits: (1 + %width) LoopDispositions: { %for.cond: Computable }
+; CHECK-NEXT: --> {1,+,1}<nuw><%for.cond> U: [1,0) S: [1,0) Exits: (1 + %width) LoopDispositions: { %for.cond: Computable }
; CHECK-NEXT: Determining loop execution counts for: @_Z4loopi
; CHECK-NEXT: Loop %for.cond: backedge-taken count is %width
; CHECK-NEXT: Loop %for.cond: max backedge-taken count is -1
diff --git a/llvm/test/Transforms/IndVarSimplify/floating-point-iv.ll b/llvm/test/Transforms/IndVarSimplify/floating-point-iv.ll
index f792e8cbd403..a70311cd055a 100644
--- a/llvm/test/Transforms/IndVarSimplify/floating-point-iv.ll
+++ b/llvm/test/Transforms/IndVarSimplify/floating-point-iv.ll
@@ -150,7 +150,7 @@ define double @test_max_be() {
; CHECK-NEXT: [[INDVAR_CONV:%.*]] = sitofp i32 [[TMP11_INT]] to double
; CHECK-NEXT: [[TMP12]] = fadd double [[TMP10]], [[INDVAR_CONV]]
; CHECK-NEXT: [[TMP13_INT]] = add nuw nsw i32 [[TMP11_INT]], 1
-; CHECK-NEXT: [[TMP14:%.*]] = icmp slt i32 [[TMP13_INT]], 99999
+; CHECK-NEXT: [[TMP14:%.*]] = icmp ult i32 [[TMP13_INT]], 99999
; CHECK-NEXT: br i1 [[TMP14]], label [[BB22]], label [[BB6:%.*]]
; CHECK: bb22:
; CHECK-NEXT: br i1 true, label [[BB8]], label [[BB6]]
@@ -189,7 +189,7 @@ define float @test_max_be2() {
; CHECK-NEXT: [[INDVAR_CONV:%.*]] = sitofp i32 [[TMP11_INT]] to float
; CHECK-NEXT: [[TMP12]] = fadd float [[TMP10]], [[INDVAR_CONV]]
; CHECK-NEXT: [[TMP13_INT]] = add nuw nsw i32 [[TMP11_INT]], 1
-; CHECK-NEXT: [[TMP14:%.*]] = icmp slt i32 [[TMP13_INT]], 99999
+; CHECK-NEXT: [[TMP14:%.*]] = icmp ult i32 [[TMP13_INT]], 99999
; CHECK-NEXT: br i1 [[TMP14]], label [[BB22]], label [[BB6:%.*]]
; CHECK: bb22:
; CHECK-NEXT: br i1 true, label [[BB8]], label [[BB6]]
@@ -229,7 +229,7 @@ define float @test_max_be3() {
; CHECK-NEXT: [[INDVAR_CONV:%.*]] = sitofp i32 [[TMP11_INT]] to float
; CHECK-NEXT: [[TMP12]] = fadd float [[TMP10]], [[INDVAR_CONV]]
; CHECK-NEXT: [[TMP13_INT]] = add nuw nsw i32 [[TMP11_INT]], 1
-; CHECK-NEXT: [[TMP14:%.*]] = icmp slt i32 [[TMP13_INT]], 99999
+; CHECK-NEXT: [[TMP14:%.*]] = icmp ult i32 [[TMP13_INT]], 99999
; CHECK-NEXT: br i1 [[TMP14]], label [[BB22]], label [[BB6:%.*]]
; CHECK: bb22:
; CHECK-NEXT: br i1 true, label [[BB8]], label [[BB6]]
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