[llvm-commits] [llvm] r136797 - in /llvm/trunk: include/llvm/Analysis/ScalarEvolution.h lib/Transforms/Utils/LoopSimplify.cpp lib/Transforms/Utils/LoopUnroll.cpp test/Transforms/LoopSimplify/preserve-scev.ll
Andrew Trick
atrick at apple.com
Wed Aug 3 11:32:11 PDT 2011
Author: atrick
Date: Wed Aug 3 13:32:11 2011
New Revision: 136797
URL: http://llvm.org/viewvc/llvm-project?rev=136797&view=rev
Log:
SCEV: Use AssertingVH to catch dangling BasicBlock* when passes forget
to notify SCEV of a change. Add forgetLoop in a couple of those places.
Modified:
llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp
llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp
llvm/trunk/test/Transforms/LoopSimplify/preserve-scev.ll
Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolution.h?rev=136797&r1=136796&r2=136797&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolution.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolution.h Wed Aug 3 13:32:11 2011
@@ -264,7 +264,7 @@
/// ExitNotTakenInfo - Information about the number of times a particular
/// loop exit may be reached before exiting the loop.
struct ExitNotTakenInfo {
- BasicBlock *ExitingBlock;
+ AssertingVH<BasicBlock> ExitingBlock;
const SCEV *ExactNotTaken;
PointerIntPair<ExitNotTakenInfo*, 1> NextExit;
Modified: llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp?rev=136797&r1=136796&r2=136797&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp Wed Aug 3 13:32:11 2011
@@ -325,6 +325,14 @@
DEBUG(dbgs() << "LoopSimplify: Eliminating exiting block "
<< ExitingBlock->getName() << "\n");
+ // If any reachable control flow within this loop has changed, notify
+ // ScalarEvolution. Currently assume the parent loop doesn't change
+ // (spliting edges doesn't count). If blocks, CFG edges, or other values
+ // in the parent loop change, then we need call to forgetLoop() for the
+ // parent instead.
+ if (SE)
+ SE->forgetLoop(L);
+
assert(pred_begin(ExitingBlock) == pred_end(ExitingBlock));
Changed = true;
LI->removeBlock(ExitingBlock);
Modified: llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp?rev=136797&r1=136796&r2=136797&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp Wed Aug 3 13:32:11 2011
@@ -58,7 +58,8 @@
/// only has one predecessor, and that predecessor only has one successor.
/// The LoopInfo Analysis that is passed will be kept consistent.
/// Returns the new combined block.
-static BasicBlock *FoldBlockIntoPredecessor(BasicBlock *BB, LoopInfo* LI) {
+static BasicBlock *FoldBlockIntoPredecessor(BasicBlock *BB, LoopInfo* LI,
+ LPPassManager *LPM) {
// Merge basic blocks into their predecessor if there is only one distinct
// pred, and if there is only one distinct successor of the predecessor, and
// if there are no PHI nodes.
@@ -90,6 +91,12 @@
std::string OldName = BB->getName();
// Erase basic block from the function...
+
+ // ScalarEvolution holds references to loop exit blocks.
+ if (ScalarEvolution *SE = LPM->getAnalysisIfAvailable<ScalarEvolution>()) {
+ if (Loop *L = LI->getLoopFor(BB))
+ SE->forgetLoop(L);
+ }
LI->removeBlock(BB);
BB->eraseFromParent();
@@ -364,7 +371,7 @@
BranchInst *Term = cast<BranchInst>(Latches[i]->getTerminator());
if (Term->isUnconditional()) {
BasicBlock *Dest = Term->getSuccessor(0);
- if (BasicBlock *Fold = FoldBlockIntoPredecessor(Dest, LI))
+ if (BasicBlock *Fold = FoldBlockIntoPredecessor(Dest, LI, LPM))
std::replace(Latches.begin(), Latches.end(), Dest, Fold);
}
}
Modified: llvm/trunk/test/Transforms/LoopSimplify/preserve-scev.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopSimplify/preserve-scev.ll?rev=136797&r1=136796&r2=136797&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopSimplify/preserve-scev.ll (original)
+++ llvm/trunk/test/Transforms/LoopSimplify/preserve-scev.ll Wed Aug 3 13:32:11 2011
@@ -48,3 +48,91 @@
}
declare void @foo() nounwind
+
+; Notify SCEV when removing an ExitingBlock.
+; CHECK: @mergeExit
+; CHECK: while.cond191:
+; CHECK: br i1 %or.cond, label %while.body197
+; CHECK-NOT: land.rhs:
+; CHECK: ret
+define void @mergeExit(i32 %MapAttrCount) nounwind uwtable ssp {
+entry:
+ br i1 undef, label %if.then124, label %if.end126
+
+if.then124: ; preds = %entry
+ unreachable
+
+if.end126: ; preds = %entry
+ br i1 undef, label %while.body.lr.ph, label %if.end591
+
+while.body.lr.ph: ; preds = %if.end126
+ br i1 undef, label %if.end140, label %if.then137
+
+if.then137: ; preds = %while.body.lr.ph
+ unreachable
+
+if.end140: ; preds = %while.body.lr.ph
+ br i1 undef, label %while.cond191.outer, label %if.then148
+
+if.then148: ; preds = %if.end140
+ unreachable
+
+while.cond191.outer: ; preds = %if.then205, %if.end140
+ br label %while.cond191
+
+while.cond191: ; preds = %while.body197, %while.cond191.outer
+ %CppIndex.0 = phi i32 [ %inc, %while.body197 ], [ undef, %while.cond191.outer ]
+ br i1 undef, label %land.rhs, label %if.then216
+
+land.rhs: ; preds = %while.cond191
+ %inc = add i32 %CppIndex.0, 1
+ %cmp196 = icmp ult i32 %inc, %MapAttrCount
+ br i1 %cmp196, label %while.body197, label %if.then216
+
+while.body197: ; preds = %land.rhs
+ br i1 undef, label %if.then205, label %while.cond191
+
+if.then205: ; preds = %while.body197
+ br label %while.cond191.outer
+
+if.then216: ; preds = %land.rhs, %while.cond191
+ br i1 undef, label %if.else, label %if.then221
+
+if.then221: ; preds = %if.then216
+ unreachable
+
+if.else: ; preds = %if.then216
+ br i1 undef, label %if.then266, label %if.end340
+
+if.then266: ; preds = %if.else
+ switch i32 undef, label %if.else329 [
+ i32 17, label %if.then285
+ i32 19, label %if.then285
+ i32 18, label %if.then285
+ i32 15, label %if.then285
+ ]
+
+if.then285: ; preds = %if.then266, %if.then266, %if.then266, %if.then266
+ br i1 undef, label %if.then317, label %if.else324
+
+if.then317: ; preds = %if.then285
+ br label %if.end340
+
+if.else324: ; preds = %if.then285
+ unreachable
+
+if.else329: ; preds = %if.then266
+ unreachable
+
+if.end340: ; preds = %if.then317, %if.else
+ unreachable
+
+if.end591: ; preds = %if.end126
+ br i1 undef, label %cond.end, label %cond.false
+
+cond.false: ; preds = %if.end591
+ unreachable
+
+cond.end: ; preds = %if.end591
+ ret void
+}
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