From ad19c8c63cae112a2677c2f5d65717aeba44f8cb Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sun, 9 Jan 2011 22:31:26 +0000 Subject: [PATCH] Step #3 to improving trip count analysis: If we fold a + {b,+,stride} into {a+b,+,stride} (because a is LIV), then the resultant AddRec is NUW/NSW if the client says it is. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123133 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ScalarEvolution.cpp | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index d3d65847cbc..89daec8053e 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -1560,10 +1560,14 @@ const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl &Ops, AddRecOps[0] = getAddExpr(LIOps); // Build the new addrec. Propagate the NUW and NSW flags if both the - // outer add and the inner addrec are guaranteed to have no overflow. - const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRecLoop, - HasNUW && AddRec->hasNoUnsignedWrap(), - HasNSW && AddRec->hasNoSignedWrap()); + // outer add and the inner addrec are guaranteed to have no overflow or if + // there is no outer part. + if (Ops.size() != 1) { + HasNUW &= AddRec->hasNoUnsignedWrap(); + HasNSW &= AddRec->hasNoSignedWrap(); + } + + const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRecLoop, HasNUW, HasNSW); // If all of the other operands were loop invariant, we are done. if (Ops.size() == 1) return NewRec;