[llvm-testresults] buildbot failure in lab.llvm.org on phase2 - living

[llvmlab-buildmaster at lab.llvm.org]

The Buildbot has detected a new failure on builder phase2 - living while building lab.llvm.org.
Full details are available at:
 http://lab.llvm.org:8013/builders/phase2%20-%20living/builds/6897

Buildbot URL: http://lab.llvm.org:8013/

Buildslave for this Build: macpro1

Build Reason: scheduler
Build Source Stamp: 200399
Blamelist: chandlerc,joerg,matheusalmeida

BUILD FAILED: failed

sincerely,
 -The Buildbot


================================================================================

CHANGES:
Files:
 lib/Transforms/Scalar/LoopRotation.cpp
 lib/Transforms/Utils/BreakCriticalEdges.cpp
 test/Transforms/LoopRotate/dbgvalue.ll
 test/Transforms/LoopRotate/preserve-loop-simplify.ll
On: smooshlab-project
At: Wed 29 Jan 2014 05:25:51
Changed By: chandlerc
Comments: [LPM] Fix PR18643, another scary place where loop transforms failed to
preserve loop simplify of enclosing loops.

The problem here starts with LoopRotation which ends up cloning code out
of the latch into the new preheader it is buidling. This can create
a new edge from the preheader into the exit block of the loop which
breaks LoopSimplify form. The code tries to fix this by splitting the
critical edge between the latch and the exit block to get a new exit
block that only the latch dominates. This sadly isn't sufficient.

The exit block may be an exit block for multiple nested loops. When we
clone an edge from the latch of the inner loop to the new preheader
being built in the outer loop, we create an exiting edge from the outer
loop to this exit block. Despite breaking the LoopSimplify form for the
inner loop, this is fine for the outer loop. However, when we split the
edge from the inner loop to the exit block, we create a new block which
is in neither the inner nor outer loop as the new exit block. This is
a predecessor to the old exit block, and so the split itself takes the
outer loop out of LoopSimplify form. We need to split every edge
entering the exit block from inside a loop nested more deeply than the
exit block in order to preserve all of the loop simplify constraints.

Once we try to do that, a problem with splitting critical edges
surfaces. Previously, we tried a very brute force to update LoopSimplify
form by re-computing it for all exit blocks. We don't need to do this,
and doing this much will sometimes but not always overlap with the
LoopRotate bug fix. Instead, the code needs to specifically handle the
cases which can start to violate LoopSimplify -- they aren't that
common. We need to see if the destination of the split edge was a loop
exit block in simplified form for the loop of the source of the edge.
For this to be true, all the predecessors need to be in the exact same
loop as the source of the edge being split. If the dest block was
originally in this form, we have to split all of the deges back into
this loop to recover it. The old mechanism of doing this was
conservatively correct because at least *one* of the exiting blocks it
rewrote was the DestBB and so the DestBB's predecessors were fixed. But
this is a much more targeted way of doing it. Making it targeted is
important, because ballooning the set of edges touched prevents
LoopRotate from being able to split edges *it* needs to split to
preserve loop simplify in a coherent way -- the critical edge splitting
would sometimes find the other edges in need of splitting but not
others.

Many, *many* thanks for help from Nick reducing these test cases
mightily. And helping lots with the analysis here as this one was quite
tricky to track down.Properties: 
  phase_id: r200393-t20140129_052752-b15848



Files:
 lib/arm/clzdi2.S
 lib/arm/clzsi2.S
On: smooshlab-project
At: Wed 29 Jan 2014 05:55:51
Changed By: joerg
Comments: Optimized implementation of __clzdi2 and __clzsi2 for ARM. Written in
collaboration with Matt Thomas.

Differential Revision: http://llvm-reviews.chandlerc.com/D2630
Properties: 
  phase_id: r200394-t20140129_055752-b15849



File: test/CodeGen/Mips/msa/elm_copy.ll
On: smooshlab-project
At: Wed 29 Jan 2014 06:01:52
Changed By: matheusalmeida
Comments: [mips][msa] CHECK-DAG-ize MSA elm_copy.ll test.

This update is a preparation for the addition of Mips64 MSA tests.

No functional changes.

Properties: 
  phase_id: r200396-t20140129_060626-b15850



Files:
 lib/arm/clzdi2.S
 lib/arm/clzsi2.S
 lib/arm/udivmodsi4.S
 lib/arm/udivsi3.S
 lib/arm/umodsi3.S
 lib/assembly.h
On: smooshlab-project
At: Wed 29 Jan 2014 06:01:52
Changed By: joerg
Comments: Move JMP/JMPc definition into assembly.h's ARM block.
Properties: 
  phase_id: r200396-t20140129_060626-b15850



Files:
 lib/arm/bswapdi2.S
 lib/arm/bswapsi2.S
 lib/arm/comparesf2.S
On: smooshlab-project
At: Wed 29 Jan 2014 06:05:51
Changed By: joerg
Comments: Support ARMv4 in the remaining non-VFP routines.
Properties: 
  phase_id: r200397-t20140129_061436-b15851



Files:
 lib/Target/Mips/MipsMSAInstrFormats.td
 lib/Target/Mips/MipsMSAInstrInfo.td
 lib/Target/Mips/MipsSEISelLowering.cpp
 test/CodeGen/Mips/msa/elm_copy.ll
 test/MC/Mips/msa/test_elm_msa64.s
On: smooshlab-project
At: Wed 29 Jan 2014 06:16:04
Changed By: matheusalmeida
Comments: [mips][msa] Add copy_{u,s}.d.

These instructions are only available on Mips64 cores
that implement the MSA ASE.

Properties: 
  phase_id: r200398-t20140129_062218-b15852



File: test/CodeGen/Mips/msa/2r_vector_scalar.ll
On: smooshlab-project
At: Wed 29 Jan 2014 06:41:51
Changed By: matheusalmeida
Comments: [mips][msa] CHECK-DAG-ize MSA 2r_vector_scalar.ll test.

This update is a preparation for the addition of Mips64 MSA tests.

No functional changes.

Properties: 
  phase_id: r200399-t20140129_064352-b15853



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