Reapply r141870, SCEV expansion of post-inc.
Speculatively reapply to see if this test case still crashes on
linux. I may have fixed it in my last checkin.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141895 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index 81f4db1..e76b6b1 100644
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -1120,6 +1120,14 @@
BasicBlock *LatchBlock = L->getLoopLatch();
assert(LatchBlock && "PostInc mode requires a unique loop latch!");
Result = PN->getIncomingValueForBlock(LatchBlock);
+
+ // For an expansion to use the postinc form, the client must call
+ // expandCodeFor with an InsertPoint that is either outside the PostIncLoop
+ // or dominated by IVIncInsertPos.
+ assert((!isa<Instruction>(Result) ||
+ SE.DT->dominates(cast<Instruction>(Result),
+ Builder.GetInsertPoint())) &&
+ "postinc expansion does not dominate use");
}
// Re-apply any non-loop-dominating scale.
@@ -1410,8 +1418,12 @@
Value *V = visit(S);
// Remember the expanded value for this SCEV at this location.
- if (PostIncLoops.empty())
- InsertedExpressions[std::make_pair(S, InsertPt)] = V;
+ //
+ // This is independent of PostIncLoops. The mapped value simply materializes
+ // the expression at this insertion point. If the mapped value happened to be
+ // a postinc expansion, it could be reused by a non postinc user, but only if
+ // its insertion point was already at the head of the loop.
+ InsertedExpressions[std::make_pair(S, InsertPt)] = V;
restoreInsertPoint(SaveInsertBB, SaveInsertPt);
return V;