Small fix in InstCombineCasts.cpp. Restored "alloca + bitcast" reducing for case when alloca's size is calculated within the "add/sub/... nsw".
Also added fix to 2011-06-13-nsw-alloca.ll test.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156231 91177308-0d34-0410-b5e6-96231b3b80d8
NVPTX: Initialize the UseF32FTZ flag.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156232 91177308-0d34-0410-b5e6-96231b3b80d8
Add a new target hook "predictableSelectIsExpensive".

This will be used to determine whether it's profitable to turn a select into a
branch when the branch is likely to be predicted.

Currently enabled for everything but Atom on X86 and Cortex-A9 devices on ARM.

I'm not entirely happy with the name of this flag, suggestions welcome ;)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156233 91177308-0d34-0410-b5e6-96231b3b80d8
CodeGenPrepare: Add a transform to turn selects into branches in some cases.

This came up when a change in block placement formed a cmov and slowed down a
hot loop by 50%:

	ucomisd	(%rdi), %xmm0
	cmovbel	%edx, %esi

cmov is a really bad choice in this context because it doesn't get branch
prediction. If we emit it as a branch, an out-of-order CPU can do a better job
(if the branch is predicted right) and avoid waiting for the slow load+compare
instruction to finish. Of course it won't help if the branch is unpredictable,
but those are really rare in practice.

This patch uses a dumb conservative heuristic, it turns all cmovs that have one
use and a direct memory operand into branches. cmovs usually save some code
size, so we disable the transform in -Os mode. In-Order architectures are
unlikely to benefit as well, those are included in the
"predictableSelectIsExpensive" flag.

It would be better to reuse branch probability info here, but BPI doesn't
support select instructions currently. It would make sense to use the same
heuristics as the if-converter pass, which does the opposite direction of this
transform.


Test suite shows a small improvement here and there on corei7-level machines,
but the actual results depend a lot on the used microarchitecture. The
transformation is currently disabled by default and available by passing the
-enable-cgp-select2branch flag to the code generator.

Thanks to Chandler for the initial test case to him and Evan Cheng for providing
me with comments and test-suite numbers that were more stable than mine :)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156234 91177308-0d34-0410-b5e6-96231b3b80d8
Update all outdated autoconf files in the sample project.

We might just use symlinks here, but I'm afraid of possible portability issues.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156235 91177308-0d34-0410-b5e6-96231b3b80d8
[build] Add build check for ::arc4random().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156236 91177308-0d34-0410-b5e6-96231b3b80d8
[Support] Add sys::Process::GetRandomNumber().
 - Primitive API, but we rarely have need for random numbers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156237 91177308-0d34-0410-b5e6-96231b3b80d8
[Support] Rewrite sys::fs::unique_file to not be stupid with /dev/urandom.
 - Just use sys::Process::GetRandomNumber instead of having two poor
   implementations.
 - This is ~70 times (!) faster on my OS X machine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156238 91177308-0d34-0410-b5e6-96231b3b80d8
[Support] Fix up comments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156239 91177308-0d34-0410-b5e6-96231b3b80d8
[Support] Add missing include.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156240 91177308-0d34-0410-b5e6-96231b3b80d8
Nuke a few dead remnants of the CBE.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156241 91177308-0d34-0410-b5e6-96231b3b80d8
refactor some code to expose column numbers more and make diagnostic printing slightly more efficient.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156243 91177308-0d34-0410-b5e6-96231b3b80d8
add missing header <shame>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156244 91177308-0d34-0410-b5e6-96231b3b80d8
revert my patches, which are causing problems.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156245 91177308-0d34-0410-b5e6-96231b3b80d8
reapply my patch, with a fix for an off-by-one error.  Turned out to be a lot
of work for a drive-by fix :)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156246 91177308-0d34-0410-b5e6-96231b3b80d8
Support/Process: Move llvm::sys::Process::GetRandomNumber() from Process.cpp to Unix/Process.inc.

FIXME: GetRandomNumber() is not implemented in Win32.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156251 91177308-0d34-0410-b5e6-96231b3b80d8
Unix/Process.inc: Give more useful random seed to srand. Workaround for PR12743.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156252 91177308-0d34-0410-b5e6-96231b3b80d8
Remove trailing spaces.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156257 91177308-0d34-0410-b5e6-96231b3b80d8
Switch the select to branch transformation on by default.

The primitive conservative heuristic seems to give a slight overall
improvement while not regressing stuff. Make it available to wider
testing. If you notice any speed regressions (or significant code
size regressions) let me know!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156258 91177308-0d34-0410-b5e6-96231b3b80d8
make SourceMgr tolerate empty SMLoc()'s better.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156260 91177308-0d34-0410-b5e6-96231b3b80d8