[llvm] r217144 - Enable noalias metadata by default and swap the order of the SLP and Loop vectorizers by default.

[Yi Kong]

Hi James,

This patch is causing a bunch of failures in LNT test suite, when
compiling with `-O3 -fslp-vectorize-aggressive`. Clang fails when
trying to do the CSE after BBVectorize.

-Yi

New Failures - Compile Time
MultiSource/Applications/ClamAV/clamscan
MultiSource/Applications/JM/ldecod/ldecod
MultiSource/Applications/JM/lencod/lencod
MultiSource/Applications/oggenc/oggenc
MultiSource/Benchmarks/7zip/7zip-benchmark
MultiSource/Benchmarks/FreeBench/neural/neural
MultiSource/Benchmarks/MallocBench/espresso/espresso
MultiSource/Benchmarks/MiBench/consumer-lame/consumer-lame
SingleSource/Benchmarks/CoyoteBench/lpbench

Error message:
$ clang lpbench.c --target=aarch64-linux-gnu -O3 -fslp-vectorize-aggressive
Instruction does not dominate all uses!
  %cmp.zero241 = icmp eq i64 %n.vec239, 0
  br i1 %cmp.zero241, label %middle.block, label %vector.memcheck
Instruction does not dominate all uses!
  %n.vec239 = and i64 %0, -4
  %37 = icmp eq i64 %index.next, %n.vec239
Instruction does not dominate all uses!
  %n.vec239 = and i64 %0, -4
  %resume.val = phi i64 [ 0, %overflow.checked ], [ 0,
%vector.memcheck ], [ %n.vec239, %vector.body ]
Instruction does not dominate all uses!
  %cmp.zero241 = icmp eq i64 %n.vec239, 0
  br i1 %cmp.zero241, label %middle.block184, label %vector.memcheck205
Instruction does not dominate all uses!
  %n.vec239 = and i64 %0, -4
  %56 = icmp eq i64 %index.next211, %n.vec239
Instruction does not dominate all uses!
  %n.vec239 = and i64 %0, -4
  %resume.val206 = phi i64 [ 0, %overflow.checked192 ], [ 0,
%vector.memcheck205 ], [ %n.vec239, %vector.body183 ]
fatal error: error in backend: Broken function found, compilation aborted!
clang: error: clang frontend command failed with exit code 70 (use -v
to see invocation)
clang version 3.6.0 (trunk 217400)
Target: aarch64--linux-gnu
Thread model: posix
clang: note: diagnostic msg: PLEASE submit a bug report to
http://llvm.org/bugs/ and include the crash backtrace, preprocessed
source, and associated run script.
clang: note: diagnostic msg:
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang: note: diagnostic msg: /tmp/lpbench-8701bf.c
clang: note: diagnostic msg: /tmp/lpbench-8701bf.sh
clang: note: diagnostic msg:

********************

On 4 September 2014 14:23, James Molloy <james.molloy at arm.com> wrote:
> Author: jamesm
> Date: Thu Sep  4 08:23:08 2014
> New Revision: 217144
>
> URL: http://llvm.org/viewvc/llvm-project?rev=217144&view=rev
> Log:
> Enable noalias metadata by default and swap the order of the SLP and Loop vectorizers by default.
>
> After some time maturing, hopefully the flags themselves will be removed.
>
> Modified:
>     llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp
>     llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
>
> Modified: llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp?rev=217144&r1=217143&r2=217144&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp (original)
> +++ llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp Thu Sep  4 08:23:08 2014
> @@ -62,7 +62,7 @@ static cl::opt<bool> RunLoadCombine("com
>
>  static cl::opt<bool>
>  RunSLPAfterLoopVectorization("run-slp-after-loop-vectorization",
> -  cl::init(false), cl::Hidden,
> +  cl::init(true), cl::Hidden,
>    cl::desc("Run the SLP vectorizer (and BB vectorizer) after the Loop "
>             "vectorizer instead of before"));
>
>
> Modified: llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp?rev=217144&r1=217143&r2=217144&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp (original)
> +++ llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp Thu Sep  4 08:23:08 2014
> @@ -42,7 +42,7 @@
>  using namespace llvm;
>
>  static cl::opt<bool>
> -EnableNoAliasConversion("enable-noalias-to-md-conversion", cl::init(false),
> +EnableNoAliasConversion("enable-noalias-to-md-conversion", cl::init(true),
>    cl::Hidden,
>    cl::desc("Convert noalias attributes to metadata during inlining."));
>
>
>
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