[polly] r233501 - Strip constant factors from SCoP parameters

[Johannes Doerfert]

On 04/08, Tobias Grosser wrote:
> On 03/29/2015 10:45 PM, Johannes Doerfert wrote:
> >Author: jdoerfert
> >Date: Sun Mar 29 15:45:09 2015
> >New Revision: 233501
> >
> >URL: http://llvm.org/viewvc/llvm-project?rev=233501&view=rev
> >Log:
> >Strip constant factors from SCoP parameters
> >
> >   This will strip the constant factor of a parameter befor we add it to
> >   the SCoP. As a result the access functions are simplified, e.g., for
> >   the attached test case.
> 
> Hi Johannes,
> 
> we just got https://llvm.org/bugs/show_bug.cgi?id=23160 reported and for me
> it breaks in:
> 
> 6  clang           0x00000000015ef059
> llvm::ScalarEvolution::isSCEVable(llvm::Type*) const + 25
> 7  clang           0x00000000015edb5f
> llvm::ScalarEvolution::getEffectiveSCEVType(llvm::Type*) const + 47
> 8  clang           0x00000000015edaef
> llvm::ScalarEvolution::getConstant(llvm::Type*, unsigned long, bool) + 47
> 9  LLVMPolly.so    0x00007f31e8ada55c
> polly::extractConstantFactor(llvm::SCEV const*, llvm::ScalarEvolution&) + 60
> 10 LLVMPolly.so    0x00007f31e8a6b3bf
> polly::Scop::addParams(std::vector<llvm::SCEV const*,
> std::allocator<llvm::SCEV const*> >) + 111
> 11 LLVMPolly.so    0x00007f31e8a6b2e4
> SCEVAffinator::getPwAff(polly::ScopStmt*, llvm::SCEV const*) + 116
> 12 LLVMPolly.so    0x00007f31e8a6df3b
> polly::MemoryAccess::MemoryAccess(polly::IRAccess const&,
> llvm::Instruction*, polly::ScopStmt*, polly::ScopArrayInfo const*) + 603
> 13 LLVMPolly.so    0x00007f31e8a6ed9f
> polly::ScopStmt::buildAccesses(polly::TempScop&, llvm::BasicBlock*, bool) +
> 383
> 
> Could this be caused by your patch?
This looks look the SCEV handed to extractConstantFactor is NULL (or
more unlikely the ScalarEvolution reference is broken). Anyhow, if it
crashes at getConstant it was broken before. 

I can look into it tomorrow.

-- 

Johannes Doerfert
Researcher / PhD Student

Compiler Design Lab (Prof. Hack)
Saarland University, Computer Science
Building E1.3, Room 4.31

Tel. +49 (0)681 302-57521 : doerfert at cs.uni-saarland.de
Fax. +49 (0)681 302-3065  : http://www.cdl.uni-saarland.de/people/doerfert
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 213 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150408/744cf741/attachment.sig>