[PATCH] D87274: [NFC] Move functon from IndVarSimplify to SCEV
Max Kazantsev via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Sep 8 21:22:00 PDT 2020
This revision was automatically updated to reflect the committed changes.
Closed by commit rG795e4ee9d2db: [NFC] Move functon from IndVarSimplify to SCEV (authored by mkazantsev).
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D87274/new/
https://reviews.llvm.org/D87274
Files:
llvm/include/llvm/Analysis/ScalarEvolution.h
llvm/lib/Analysis/ScalarEvolution.cpp
llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
Index: llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -2329,36 +2329,6 @@
return MadeAnyChanges;
}
-/// Return a symbolic upper bound for the backedge taken count of the loop.
-/// This is more general than getConstantMaxBackedgeTakenCount as it returns
-/// an arbitrary expression as opposed to only constants.
-/// TODO: Move into the ScalarEvolution class.
-static const SCEV* getMaxBackedgeTakenCount(ScalarEvolution &SE,
- DominatorTree &DT, Loop *L) {
- SmallVector<BasicBlock*, 16> ExitingBlocks;
- L->getExitingBlocks(ExitingBlocks);
-
- // Form an expression for the maximum exit count possible for this loop. We
- // merge the max and exact information to approximate a version of
- // getConstantMaxBackedgeTakenCount which isn't restricted to just constants.
- SmallVector<const SCEV*, 4> ExitCounts;
- for (BasicBlock *ExitingBB : ExitingBlocks) {
- const SCEV *ExitCount = SE.getExitCount(L, ExitingBB);
- if (isa<SCEVCouldNotCompute>(ExitCount))
- ExitCount = SE.getExitCount(L, ExitingBB,
- ScalarEvolution::ConstantMaximum);
- if (!isa<SCEVCouldNotCompute>(ExitCount)) {
- assert(DT.dominates(ExitingBB, L->getLoopLatch()) &&
- "We should only have known counts for exiting blocks that "
- "dominate latch!");
- ExitCounts.push_back(ExitCount);
- }
- }
- if (ExitCounts.empty())
- return SE.getCouldNotCompute();
- return SE.getUMinFromMismatchedTypes(ExitCounts);
-}
-
bool IndVarSimplify::optimizeLoopExits(Loop *L, SCEVExpander &Rewriter) {
SmallVector<BasicBlock*, 16> ExitingBlocks;
L->getExitingBlocks(ExitingBlocks);
@@ -2391,7 +2361,7 @@
return false;
// Get a symbolic upper bound on the loop backedge taken count.
- const SCEV *MaxExitCount = getMaxBackedgeTakenCount(*SE, *DT, L);
+ const SCEV *MaxExitCount = SE->computeMaxBackedgeTakenCount(L);
if (isa<SCEVCouldNotCompute>(MaxExitCount))
return false;
Index: llvm/lib/Analysis/ScalarEvolution.cpp
===================================================================
--- llvm/lib/Analysis/ScalarEvolution.cpp
+++ llvm/lib/Analysis/ScalarEvolution.cpp
@@ -12506,3 +12506,28 @@
MatchURemWithDivisor(getNegativeSCEV(Mul->getOperand(0)));
return false;
}
+
+const SCEV* ScalarEvolution::computeMaxBackedgeTakenCount(const Loop *L) {
+ SmallVector<BasicBlock*, 16> ExitingBlocks;
+ L->getExitingBlocks(ExitingBlocks);
+
+ // Form an expression for the maximum exit count possible for this loop. We
+ // merge the max and exact information to approximate a version of
+ // getConstantMaxBackedgeTakenCount which isn't restricted to just constants.
+ SmallVector<const SCEV*, 4> ExitCounts;
+ for (BasicBlock *ExitingBB : ExitingBlocks) {
+ const SCEV *ExitCount = getExitCount(L, ExitingBB);
+ if (isa<SCEVCouldNotCompute>(ExitCount))
+ ExitCount = getExitCount(L, ExitingBB,
+ ScalarEvolution::ConstantMaximum);
+ if (!isa<SCEVCouldNotCompute>(ExitCount)) {
+ assert(DT.dominates(ExitingBB, L->getLoopLatch()) &&
+ "We should only have known counts for exiting blocks that "
+ "dominate latch!");
+ ExitCounts.push_back(ExitCount);
+ }
+ }
+ if (ExitCounts.empty())
+ return getCouldNotCompute();
+ return getUMinFromMismatchedTypes(ExitCounts);
+}
Index: llvm/include/llvm/Analysis/ScalarEvolution.h
===================================================================
--- llvm/include/llvm/Analysis/ScalarEvolution.h
+++ llvm/include/llvm/Analysis/ScalarEvolution.h
@@ -768,6 +768,11 @@
return getBackedgeTakenCount(L, ConstantMaximum);
}
+ /// Return a symbolic upper bound for the backedge taken count of the loop.
+ /// This is more general than getConstantMaxBackedgeTakenCount as it returns
+ /// an arbitrary expression as opposed to only constants.
+ const SCEV* computeMaxBackedgeTakenCount(const Loop *L);
+
/// Return true if the backedge taken count is either the value returned by
/// getConstantMaxBackedgeTakenCount or zero.
bool isBackedgeTakenCountMaxOrZero(const Loop *L);
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