We branch to the successor with higher edge weight first.
Convert from
     je    LBB4_8  --> to outer loop
     jmp   LBB4_14 --> to inner loop
to
     jne   LBB4_14
     jmp   LBB4_8

PR12750
rdar: 11393714

llvm-svn: 161018

llvm-svn: 161010

llvm-svn: 161007

llvm-svn: 161004

This lets traces include the final iteration of a nested loop above the
center block, and the first iteration of a nested loop below the center
block.

We still don't allow traces to contain backedges, and traces are
truncated where they would leave a loop, as seen from the center block.

llvm-svn: 161003

llvm-svn: 160997

When computing a trace, all the candidates for pred/succ must have been
visited. Filter out back-edges first, though. The PO traversal ignores
them.

Thanks to Andy for spotting this in review.

llvm-svn: 160995

By overriding Pass::verifyAnalysis(), the pass contents will be verified
by the pass manager.

llvm-svn: 160994

Consider address spaces for hashing and CSEing DAG nodes.  Otherwise two loads from different x86 segments but the same address would get CSEd

llvm-svn: 160987

This is a cleaned up version of the isFree() function in
MachineTraceMetrics.cpp.

Transient instructions are very unlikely to produce any code in the
final output. Either because they get eliminated by RegisterCoalescing,
or because they are pseudo-instructions like labels and debug values.

llvm-svn: 160977

This function verifies the consistency of cached data in the
MachineTraceMetrics analysis.

llvm-svn: 160976

The MachineTraceMetrics analysis must be invalidated before modifying
the CFG. This will catch some of the violations of that rule.

llvm-svn: 160969

A->isPredecessor(B) is the same as B->isSuccessor(A), but it can
tolerate a B that is null or dangling. This shouldn't happen normally,
but it it useful for verification code.

llvm-svn: 160968

llvm-svn: 160927

Machine CSE and other optimizations can remove instructions so folding
is possible at peephole while not possible at ISel.

rdar://10554090 and rdar://11873276

llvm-svn: 160919

Jakob fixed ProcessImplicifDefs in r159149.

llvm-svn: 160910

llvm-svn: 160905

This makes it possible to quickly detect blocks that are outside the
trace.

llvm-svn: 160904

all tests accordingly.

Fixes PR13351.

Patch by shinichiro hamaji!

llvm-svn: 160899

llvm-svn: 160898

A value number is a PHI def if and only if it begins at a block
boundary. This can be derived from the def slot, a separate flag is not
necessary.

llvm-svn: 160893

This option replaces the existing live interval computation with one
based on LiveRangeCalc.cpp. The new algorithm does not depend on
LiveVariables, and it can be run at any time, before or after leaving
SSA form.

llvm-svn: 160892

Patch by Tyler Nowicki!

llvm-svn: 160888

llvm-svn: 160798

This is still a work in progress.

Out-of-order CPUs usually execute instructions from multiple basic
blocks simultaneously, so it is necessary to look at longer traces when
estimating the performance effects of code transformations.

The MachineTraceMetrics analysis will pick a typical trace through a
given basic block and provide performance metrics for the trace. Metrics
will include:

- Instruction count through the trace.
- Issue count per functional unit.
- Critical path length, and per-instruction 'slack'.

These metrics can be used to determine the performance limiting factor
when executing the trace, and how it will be affected by a code
transformation.

Initially, this will be used by the early if-conversion pass.

llvm-svn: 160796

llvm-svn: 160791

It is redundant; RegisterCoalescer will do the remat if it can't eliminate
the copy. Collected instruction counts before and after this. A few extra
instructions are generated due to spilling but it is normal to see these kinds
of changes with almost any small codegen change, according to Jakob.

This also fixed rdar://11830760 where xor is expected instead of movi0.

llvm-svn: 160749

When a live range splits into multiple connected components, we would
arbitrarily assign <undef> uses to component 0. This is wrong when the
use is tied to a def that gets assigned to a different component:

  %vreg69<def> = ADD8ri %vreg68<undef>, 1

The use and def must get the same virtual register.

Fix this by assigning <undef> uses to the same component as the value
defined by the instruction, if any:

  %vreg69<def> = ADD8ri %vreg69<undef>, 1

This fixes PR13402. The PR has a test case which I am not including
because it is unlikely to keep exposing this behavior in the future.

llvm-svn: 160739

Include <undef> operands and virtual registers after leaving SSA form.

llvm-svn: 160734

Change llvm_unreachable in SplitVectorOperand to report_fatal_error. Keeps release builds from crashing if code uses an intrinsic with an illegal type.

llvm-svn: 160661

llvm-svn: 160621

that do not support it (X86 does not lower select_cc).

PR: 13428

Together with Michael Kuperstein <michael.m.kuperstein@intel.com>

llvm-svn: 160619

llvm-svn: 160617

Change llvm_unreachable in SplitVectorResult to report_fatal_error. Keeps release builds from crashing if code uses an intrinsic with an illegal type. For instance 256-bit AVX intrinsics without having AVX enabled.

llvm-svn: 160616

Remove unused private member variables uncovered by the recent changes to clang's -Wunused-private-field.

llvm-svn: 160583

LiveRangeEdit::foldAsLoad() can eliminate a register by folding a load
into its only use. Only do that when the load is safe to move, and it
won't extend any live ranges.

This fixes PR13414.

llvm-svn: 160575

PHIElimination splits critical edges when it predicts it can resolve
interference and eliminate copies. It doesn't split the edge if the
interference wouldn't be resolved anyway because the phi-use register is
live in the critical edge anyway.

Teach PHIElimination to split loop exiting edges with interference, even
if it wouldn't resolve the interference. This removes the necessary
copies from the loop, which is still an improvement from injecting the
copies into the loop.

The test case demonstrates the improvement. Before:

LBB0_1:
  cmpb  $0, (%rdx)
  leaq  1(%rdx), %rdx
  movl  %esi, %eax
  je  LBB0_1

After:

LBB0_1:
  cmpb  $0, (%rdx)
  leaq  1(%rdx), %rdx
  je  LBB0_1

  movl  %esi, %eax

llvm-svn: 160571

llvm-svn: 160531

No functionality change.

llvm-svn: 160501

llvm-svn: 160493