From: Andrew Trick <atrick@apple.com>
Date: Sat, 10 Dec 2011 00:25:00 +0000 (+0000)
Subject: LSR: ignore strides in outer loops.
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=fa1948a40f14d98c1a31a2ec19035a2d5254e854;p=oota-llvm.git

LSR: ignore strides in outer loops.

Since we're not rewriting IVs in other loops, there's not much reason
to consider their stride when generating formulae.
This should reduce the number of useless formulas considered by LSR.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146302 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 7867d9fad34..ad2f52d8ec7 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2061,7 +2061,8 @@ void LSRInstance::CollectInterestingTypesAndFactors() {
     do {
       const SCEV *S = Worklist.pop_back_val();
       if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
-        Strides.insert(AR->getStepRecurrence(SE));
+        if (EnableNested || AR->getLoop() == L)
+          Strides.insert(AR->getStepRecurrence(SE));
         Worklist.push_back(AR->getStart());
       } else if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
         Worklist.append(Add->op_begin(), Add->op_end());