Handle a corner case with IV chain collection with bailout instead of assert.
Fixes PR11783: bad cast to AddRecExpr.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148572 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 42f45ae..5aee483 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2484,11 +2484,15 @@
DEBUG(dbgs() << "IV Chain Limit\n");
return;
}
+ LastIncExpr = SE.getSCEV(NextIV);
+ // IVUsers may have skipped over sign/zero extensions. We don't currently
+ // attempt to form chains involving extensions unless they can be hoisted
+ // into this loop's AddRec.
+ if (!isa<SCEVAddRecExpr>(LastIncExpr))
+ return;
++NChains;
IVChainVec.resize(NChains);
ChainUsersVec.resize(NChains);
- LastIncExpr = SE.getSCEV(NextIV);
- assert(isa<SCEVAddRecExpr>(LastIncExpr) && "expect recurrence at IV user");
DEBUG(dbgs() << "IV Head: (" << *UserInst << ") IV=" << *LastIncExpr
<< "\n");
}