From: Sanjoy Das <sanjoy@playingwithpointers.com>
Date: Tue, 25 Apr 2017 06:53:25 +0000 (+0000)
Subject: [IVUsers] Don't bail out of normalizing non-affine add recs
X-Git-Tag: llvmorg-5.0.0-rc1~6754
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=561247a8238a094bc4aa35376a2fd076bef51fe6;p=platform%2Fupstream%2Fllvm.git

[IVUsers] Don't bail out of normalizing non-affine add recs

Summary:
In a previous change I changed SCEV's normalization / denormalization
to work with non-affine add recs.  So the bailout in IVUsers can be
removed.

Reviewers: atrick, efriedma

Reviewed By: atrick

Subscribers: davide, mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D32105

llvm-svn: 301298
---

diff --git a/llvm/lib/Analysis/IVUsers.cpp b/llvm/lib/Analysis/IVUsers.cpp
index fde805a..c30feb9 100644
--- a/llvm/lib/Analysis/IVUsers.cpp
+++ b/llvm/lib/Analysis/IVUsers.cpp
@@ -253,18 +253,8 @@ bool IVUsers::AddUsersImpl(Instruction *I,
       const SCEV *OriginalISE = ISE;
 
       auto NormalizePred = [&](const SCEVAddRecExpr *AR) {
-        // We only allow affine AddRecs to be normalized, otherwise we would not
-        // be able to correctly denormalize.
-        // e.g. {1,+,3,+,2} == {-2,+,1,+,2} + {3,+,2}
-        // Normalized form:   {-2,+,1,+,2}
-        // Denormalized form: {1,+,3,+,2}
-        //
-        // However, denormalization would use a different step expression than
-        // normalization (see getPostIncExpr), generating the wrong final
-        // expression: {-2,+,1,+,2} + {1,+,2} => {-1,+,3,+,2}
         auto *L = AR->getLoop();
-        bool Result =
-            AR->isAffine() && IVUseShouldUsePostIncValue(User, I, L, DT);
+        bool Result = IVUseShouldUsePostIncValue(User, I, L, DT);
         if (Result)
           NewUse.PostIncLoops.insert(L);
         return Result;
diff --git a/llvm/test/Analysis/IVUsers/quadradic-exit-value.ll b/llvm/test/Analysis/IVUsers/quadradic-exit-value.ll
index 214afcb..6d4f1b0 100644
--- a/llvm/test/Analysis/IVUsers/quadradic-exit-value.ll
+++ b/llvm/test/Analysis/IVUsers/quadradic-exit-value.ll
@@ -36,7 +36,7 @@ exit:
 ; sure they aren't marked as post-inc users.
 ;
 ; CHECK-LABEL: IV Users for loop %test2.loop
-; CHECK-NO-LCSSA: %sext.us = {0,+,(16777216 + (-16777216 * %sub.us))<nuw><nsw>,+,33554432}<%test2.loop> in %f = ashr i32 %sext.us, 24
+; CHECK-NO-LCSSA: %sext.us = {0,+,(16777216 + (-16777216 * %sub.us))<nuw><nsw>,+,33554432}<%test2.loop> (post-inc with loop %test2.loop) in    %f = ashr i32 %sext.us, 24
 define i32 @test2() {
 entry:
   br label %test2.loop