[llvm] 16cf666 - [Loop] Move block and loop dispo invalidation to makeLoopInvariant.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 14 13:58:46 PDT 2022
Author: Florian Hahn
Date: 2022-10-14T21:58:14+01:00
New Revision: 16cf666bb7f574bc56cc0a5caf859de7c1c22704
URL: https://github.com/llvm/llvm-project/commit/16cf666bb7f574bc56cc0a5caf859de7c1c22704
DIFF: https://github.com/llvm/llvm-project/commit/16cf666bb7f574bc56cc0a5caf859de7c1c22704.diff
LOG: [Loop] Move block and loop dispo invalidation to makeLoopInvariant.
makeLoopInvariant may recursively move its operands to make them
invariant, before moving the passed in instruction. Those recursively
moved instructions are currently missed when invalidating block and loop
dispositions.
To address this, move the invalidation code to Loop::makeLoopInvariant.
Fixes #58314.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D135909
Added:
llvm/test/Transforms/LoopDeletion/invalidate-scev-after-hoisting.ll
Modified:
llvm/include/llvm/Analysis/LoopInfo.h
llvm/lib/Analysis/LoopInfo.cpp
llvm/lib/Transforms/Scalar/LoopDeletion.cpp
llvm/lib/Transforms/Utils/LoopSimplify.cpp
Removed:
llvm/test/Transforms/LoopDeletion/pr57837-invalidate-scev-after-hoisting.ll
################################################################################
diff --git a/llvm/include/llvm/Analysis/LoopInfo.h b/llvm/include/llvm/Analysis/LoopInfo.h
index 5a4f8f1430930..eb0b9efb4a0ac 100644
--- a/llvm/include/llvm/Analysis/LoopInfo.h
+++ b/llvm/include/llvm/Analysis/LoopInfo.h
@@ -583,7 +583,8 @@ class LLVM_EXTERNAL_VISIBILITY Loop : public LoopBase<BasicBlock, Loop> {
///
bool makeLoopInvariant(Value *V, bool &Changed,
Instruction *InsertPt = nullptr,
- MemorySSAUpdater *MSSAU = nullptr) const;
+ MemorySSAUpdater *MSSAU = nullptr,
+ ScalarEvolution *SE = nullptr) const;
/// If the given instruction is inside of the loop and it can be hoisted, do
/// so to make it trivially loop-invariant.
@@ -597,7 +598,8 @@ class LLVM_EXTERNAL_VISIBILITY Loop : public LoopBase<BasicBlock, Loop> {
///
bool makeLoopInvariant(Instruction *I, bool &Changed,
Instruction *InsertPt = nullptr,
- MemorySSAUpdater *MSSAU = nullptr) const;
+ MemorySSAUpdater *MSSAU = nullptr,
+ ScalarEvolution *SE = nullptr) const;
/// Check to see if the loop has a canonical induction variable: an integer
/// recurrence that starts at 0 and increments by one each time through the
diff --git a/llvm/lib/Analysis/LoopInfo.cpp b/llvm/lib/Analysis/LoopInfo.cpp
index 693b9ebd450a8..90077aaf423f1 100644
--- a/llvm/lib/Analysis/LoopInfo.cpp
+++ b/llvm/lib/Analysis/LoopInfo.cpp
@@ -68,15 +68,16 @@ bool Loop::hasLoopInvariantOperands(const Instruction *I) const {
}
bool Loop::makeLoopInvariant(Value *V, bool &Changed, Instruction *InsertPt,
- MemorySSAUpdater *MSSAU) const {
+ MemorySSAUpdater *MSSAU,
+ ScalarEvolution *SE) const {
if (Instruction *I = dyn_cast<Instruction>(V))
- return makeLoopInvariant(I, Changed, InsertPt, MSSAU);
+ return makeLoopInvariant(I, Changed, InsertPt, MSSAU, SE);
return true; // All non-instructions are loop-invariant.
}
bool Loop::makeLoopInvariant(Instruction *I, bool &Changed,
- Instruction *InsertPt,
- MemorySSAUpdater *MSSAU) const {
+ Instruction *InsertPt, MemorySSAUpdater *MSSAU,
+ ScalarEvolution *SE) const {
// Test if the value is already loop-invariant.
if (isLoopInvariant(I))
return true;
@@ -97,7 +98,7 @@ bool Loop::makeLoopInvariant(Instruction *I, bool &Changed,
}
// Don't hoist instructions with loop-variant operands.
for (Value *Operand : I->operands())
- if (!makeLoopInvariant(Operand, Changed, InsertPt, MSSAU))
+ if (!makeLoopInvariant(Operand, Changed, InsertPt, MSSAU, SE))
return false;
// Hoist.
@@ -113,6 +114,9 @@ bool Loop::makeLoopInvariant(Instruction *I, bool &Changed,
// information to the optimizer.
I->dropUnknownNonDebugMetadata();
+ if (SE)
+ SE->forgetBlockAndLoopDispositions(I);
+
Changed = true;
return true;
}
diff --git a/llvm/lib/Transforms/Scalar/LoopDeletion.cpp b/llvm/lib/Transforms/Scalar/LoopDeletion.cpp
index f19f53e8153d3..bcc038cb25c4d 100644
--- a/llvm/lib/Transforms/Scalar/LoopDeletion.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopDeletion.cpp
@@ -90,17 +90,11 @@ static bool isLoopDead(Loop *L, ScalarEvolution &SE,
break;
if (Instruction *I = dyn_cast<Instruction>(incoming)) {
- bool InstrMoved = false;
- if (!L->makeLoopInvariant(I, InstrMoved, Preheader->getTerminator())) {
+ if (!L->makeLoopInvariant(I, Changed, Preheader->getTerminator(),
+ /*MSSAU=*/nullptr, &SE)) {
AllEntriesInvariant = false;
break;
}
- Changed |= InstrMoved;
- if (InstrMoved) {
- // Moving I to a
diff erent location may change its block disposition,
- // so invalidate its SCEV.
- SE.forgetBlockAndLoopDispositions(I);
- }
}
}
}
diff --git a/llvm/lib/Transforms/Utils/LoopSimplify.cpp b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
index f247a7eb33f87..8943b4bb651f6 100644
--- a/llvm/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
@@ -647,19 +647,12 @@ static bool simplifyOneLoop(Loop *L, SmallVectorImpl<Loop *> &Worklist,
Instruction *Inst = &*I++;
if (Inst == CI)
continue;
- bool InstInvariant = false;
if (!L->makeLoopInvariant(
- Inst, InstInvariant,
- Preheader ? Preheader->getTerminator() : nullptr, MSSAU)) {
+ Inst, AnyInvariant,
+ Preheader ? Preheader->getTerminator() : nullptr, MSSAU, SE)) {
AllInvariant = false;
break;
}
- if (InstInvariant && SE) {
- // The loop disposition of all SCEV expressions that depend on any
- // hoisted values have also changed.
- SE->forgetBlockAndLoopDispositions(Inst);
- }
- AnyInvariant |= InstInvariant;
}
if (AnyInvariant)
Changed = true;
diff --git a/llvm/test/Transforms/LoopDeletion/pr57837-invalidate-scev-after-hoisting.ll b/llvm/test/Transforms/LoopDeletion/invalidate-scev-after-hoisting.ll
similarity index 82%
rename from llvm/test/Transforms/LoopDeletion/pr57837-invalidate-scev-after-hoisting.ll
rename to llvm/test/Transforms/LoopDeletion/invalidate-scev-after-hoisting.ll
index 3f70e7074b84a..27afb44a4ab48 100644
--- a/llvm/test/Transforms/LoopDeletion/pr57837-invalidate-scev-after-hoisting.ll
+++ b/llvm/test/Transforms/LoopDeletion/invalidate-scev-after-hoisting.ll
@@ -9,8 +9,8 @@
; CHECK-NEXT: Loop %inner: max backedge-taken count is 405
; CHECK-NEXT: Loop %inner: Predicated backedge-taken count is (405 + %invar)<nuw><nsw>
-define void @test() {
-; CHECK-LABEL: @test(
+define void @test_pr57837() {
+; CHECK-LABEL: @test_pr57837(
; CHECK-NEXT: bb:
; CHECK-NEXT: br label [[OUTER_HEADER:%.*]]
; CHECK: outer.header:
@@ -126,3 +126,37 @@ outer.latch:
%outer.iv.next = add nsw i32 %l, %trunc
br label %outer.header
}
+
+define void @test_pr58314() {
+; CHECK-LABEL: @test_pr58314(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[OUTER_HEADER:%.*]]
+; CHECK: outer.header:
+; CHECK-NEXT: [[C:%.*]] = icmp ne i16 0, 0
+; CHECK-NEXT: [[SEL:%.*]] = select i1 [[C]], i1 false, i1 true
+; CHECK-NEXT: br label [[INNER:%.*]]
+; CHECK: inner:
+; CHECK-NEXT: br i1 true, label [[INNER]], label [[OUTER_LATCH:%.*]]
+; CHECK: outer.latch:
+; CHECK-NEXT: [[SEL_LCSSA:%.*]] = phi i1 [ [[SEL]], [[INNER]] ]
+; CHECK-NEXT: br i1 [[SEL_LCSSA]], label [[OUTER_HEADER]], label [[EXIT:%.*]]
+; CHECK: exit:
+; CHECK-NEXT: ret void
+;
+entry:
+ br label %outer.header
+
+outer.header:
+ br label %inner
+
+inner:
+ %c = icmp ne i16 0, 0
+ %sel = select i1 %c, i1 false, i1 true
+ br i1 true, label %inner, label %outer.latch
+
+outer.latch:
+ br i1 %sel, label %outer.header, label %exit
+
+exit:
+ ret void
+}
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