Delete code for folding undefs in ScalarEvolution. It's invalid in

obscure ways, and it isn't actually important in the real world.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159969 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index b8c92f83d9fc1dd7b5a84491f6ccae1390fa1e7e..884ceec7a00bd1e107a0064f46affdfc2a7ce928 100644 (file)
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -878,13 +878,6 @@ const SCEV *ScalarEvolution::getTruncateExpr(const SCEV *Op,
     return getAddRecExpr(Operands, AddRec->getLoop(), SCEV::FlagAnyWrap);
   }
 
-  // As a special case, fold trunc(undef) to undef. We don't want to
-  // know too much about SCEVUnknowns, but this special case is handy
-  // and harmless.
-  if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(Op))
-    if (isa<UndefValue>(U->getValue()))
-      return getSCEV(UndefValue::get(Ty));
-
   // The cast wasn't folded; create an explicit cast node. We can reuse
   // the existing insert position since if we get here, we won't have
   // made any changes which would invalidate it.
@@ -1344,13 +1337,6 @@ const SCEV *ScalarEvolution::getAnyExtendExpr(const SCEV *Op,
     return getAddRecExpr(Ops, AR->getLoop(), SCEV::FlagNW);
   }
 
-  // As a special case, fold anyext(undef) to undef. We don't want to
-  // know too much about SCEVUnknowns, but this special case is handy
-  // and harmless.
-  if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(Op))
-    if (isa<UndefValue>(U->getValue()))
-      return getSCEV(UndefValue::get(Ty));
-
   // If the expression is obviously signed, use the sext cast value.
   if (isa<SCEVSMaxExpr>(Op))
     return SExt;