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author | Tom Stellard <thomas.stellard@amd.com> | 2014-04-08 21:18:17 +0000 |
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committer | Tom Stellard <thomas.stellard@amd.com> | 2014-04-08 21:18:17 +0000 |
commit | dfe482bddddf3a03cdb1f5130e0af9e502b19d85 (patch) | |
tree | 5f1c441d3f2ce16866d4f485bcbb182fde6cd442 /lib | |
parent | 76bf269759e5e18566e2cb3af119c1f509eba110 (diff) | |
download | llvm-dfe482bddddf3a03cdb1f5130e0af9e502b19d85.tar.gz llvm-dfe482bddddf3a03cdb1f5130e0af9e502b19d85.tar.bz2 llvm-dfe482bddddf3a03cdb1f5130e0af9e502b19d85.tar.xz |
Merging r203719:
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r203719 | mzolotukhin | 2014-03-12 17:31:05 -0400 (Wed, 12 Mar 2014) | 4 lines
PR17473:
Don't normalize an expression during postinc transformation unless it's
invertible.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_34@205797 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Analysis/IVUsers.cpp | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/lib/Analysis/IVUsers.cpp b/lib/Analysis/IVUsers.cpp index b33e2cb999..5a06cdce30 100644 --- a/lib/Analysis/IVUsers.cpp +++ b/lib/Analysis/IVUsers.cpp @@ -187,15 +187,34 @@ bool IVUsers::AddUsersImpl(Instruction *I, if (AddUserToIVUsers) { // Okay, we found a user that we cannot reduce. - IVUses.push_back(new IVStrideUse(this, User, I)); - IVStrideUse &NewUse = IVUses.back(); + IVStrideUse &NewUse = AddUser(User, I); // Autodetect the post-inc loop set, populating NewUse.PostIncLoops. // The regular return value here is discarded; instead of recording // it, we just recompute it when we need it. + const SCEV *OriginalISE = ISE; ISE = TransformForPostIncUse(NormalizeAutodetect, ISE, User, I, NewUse.PostIncLoops, *SE, *DT); + + // PostIncNormalization effectively simplifies the expression under + // pre-increment assumptions. Those assumptions (no wrapping) might not + // hold for the post-inc value. Catch such cases by making sure the + // transformation is invertible. + if (OriginalISE != ISE) { + const SCEV *DenormalizedISE = + TransformForPostIncUse(Denormalize, ISE, User, I, + NewUse.PostIncLoops, *SE, *DT); + + // If we normalized the expression, but denormalization doesn't give the + // original one, discard this user. + if (OriginalISE != DenormalizedISE) { + DEBUG(dbgs() << " DISCARDING (NORMALIZATION ISN'T INVERTIBLE): " + << *ISE << '\n'); + IVUses.pop_back(); + return false; + } + } DEBUG(if (SE->getSCEV(I) != ISE) dbgs() << " NORMALIZED TO: " << *ISE << '\n'); } |