register pressure and thus excess spills, which we don't currently recover from well.  This should
be re-evaluated in the future if our ability to generate good spills/splits improves.

Partial fix for <rdar://problem/7635585>.

llvm-svn: 114919

This reverts revision 114633. It was breaking llvm-gcc-i386-linux-selfhost.

It seems there is a downstream bug that is exposed by
-cgp-critical-edge-splitting=0. When that bug is fixed, this patch can go back
in.

Note that the changes to tailcallfp2.ll are not reverted. They were good are
required.

llvm-svn: 114859

llvm-svn: 114841

LoadPRE was not properly checking that the load it was PRE'ing post-dominated the block it was being hoisted to.
Splitting critical edges at the merge point only addressed part of the issue; it is also possible for non-post-domination
to occur when the path from the load to the merge has branches in it.  Unfortunately, full anticipation analysis is
time-consuming, so for now approximate it.  This is strictly more conservative than real anticipation, so we will miss
some cases that real PRE would allow, but we also no longer insert loads into paths where they didn't exist before. :-)

This is a very slight net positive on SPEC for me (0.5% on average).  Most of the benchmarks are largely unaffected, but
when it pays off it pays off decently: 181.mcf improves by 4.5% on my machine.

llvm-svn: 114785

of the source, not the original alignment since it may no longer
be valid.

Fixes rdar://8400094

llvm-svn: 114781

llvm-svn: 114750

"external" even when doing lazy bitcode loading.  This was broken because
a function that is not materialized fails the !isDeclaration() test.

llvm-svn: 114666

break critical edges on demand.

llvm-svn: 114633

truncates are free only in the case where the extended type is legal but the
load type is not.  If both types are illegal, such as when they are too big,
the load may not be legalized into an extended load.

llvm-svn: 114568

load when the type of the load is not legal, even if truncates are not free.
The load is going to be legalized to an extending load anyway.

llvm-svn: 114488

llvm-svn: 114487

llvm-svn: 114278

llvm-svn: 114277

to optimize unreachable blocks.

llvm-svn: 114105

walking the asm arguments once and stashing their Values.  This is
wrong because the same memory location can be in the list twice, and
if the first one has a sunkaddr substituted, the stashed value for the
second one will be wrong (use-after-free).  PR 8154.

llvm-svn: 114104

attribute(used).

llvm-svn: 113911

on by default and has received significant testing.

llvm-svn: 113852

deleted.  Fix this by doing the copyValue's before we delete stuff!

The testcase only repros the problem on my system with valgrind.

llvm-svn: 113820

This reverts commit r113632

Conflicts:

	cmake/modules/AddLLVM.cmake

llvm-svn: 113819

llvm-svn: 113769

llvm-svn: 113766

to expose greater opportunities for store narrowing in codegen.  This patch fixes a potential
infinite loop in instcombine caused by one of the introduced transforms being overly aggressive.

llvm-svn: 113763

on to Owen.

llvm-svn: 113720

This can result in increased opportunities for store narrowing in code generation.  Update a number of
tests for this change.  This fixes <rdar://problem/8285027>.

Additionally, because this inverts the order of ors and ands, some patterns for optimizing or-of-and-of-or
no longer fire in instances where they did originally.  Add a simple transform which recaptures most of these
opportunities: if we have an or-of-constant-or and have failed to fold away the inner or, commute the order 
of the two ors, to give the non-constant or a chance for simplification instead.

llvm-svn: 113679

llvm-svn: 113647

llvm-svn: 113632

llvm-svn: 113608

Lower the unrolling theshold to 150.  Empirical tests indicate that this is a sweet spot in the performance per
code size increase curve.

llvm-svn: 113595

not unrolling loops that contain calls that would be better off getting inlined.  This mostly
comes up when an interleaved devirtualization pass has devirtualized a call which the inliner
will inline on a future pass.  Thus, rather than blocking all loops containing calls, add
a metric for "inline candidate calls" and block loops containing those instead.

llvm-svn: 113535

Revert r113439, which relaxed the requirement that loops containing calls cannot be unrolled.  After some discussion,
there seems to be a better way to achieve the same effect.

llvm-svn: 113528

llvm-svn: 113527

llvm-svn: 113526

Next step is to recalculate the threshold values given this new heuristic.

llvm-svn: 113525

Relax the "don't unroll loops containing calls" rule.  Instead, when a loop contains a call, lower the
unrolling threshold to the optimize-for-size threshold.  Basically, for loops containing calls, unrolling
can still be profitable as long as the loop is REALLY small.

llvm-svn: 113439

Generalize instcombine's support for combining multiple bit checks into a single test.  Patch by Dirk Steinke!

llvm-svn: 113423

The threshold value of 50 is arbitrary, and I chose it simply by analogy to the inlining thresholds, where
the baseline unrolling threshold is slightly smaller than the baseline inlining threshold.  This could
undoubtedly use some tuning.

llvm-svn: 113306

turning (fptrunc (sqrt (fpext x))) -> (sqrtf x)  is great, but we have
to delete the original sqrt as well.  Not doing so causes us to do 
two sqrt's when building with -fmath-errno (the default on linux).

llvm-svn: 113260

Switch from isWeakForLinker to mayBeOverridden which is more accurate.

Add more statistics and debugging info. Add comments. Move static function
outside anonymous namespace.

llvm-svn: 113190

llvm-svn: 113146

in the duplicated block instead of duplicating them.  

Duplicating them into the end of the loop and the preheader 
means that we got a phi node in the header of the loop, 
which prevented LICM from hoisting them.  GVN would
usually come around later and merge the duplicated 
instructions so we'd get reasonable output... except that
anything dependent on the shoulda-been-hoisted value can't
be hoisted.  In PR5319 (which this fixes), a memory value
didn't get promoted.

llvm-svn: 113134