Commit Graph

3662 Commits

Author SHA1 Message Date
Eli Friedman
e3502119ae Preserve domtree and loop-simplify for runtime unrolling.
Mostly straightforward changes; we just didn't do the computation before.
One sort of interesting change in LoopUnroll.cpp: we weren't handling
dominance for children of the loop latch correctly, but
foldBlockIntoPredecessor hid the problem for complete unrolling.

Currently punting on loop peeling; made some minor changes to isolate
that problem to LoopUnrollPeel.cpp.

Adds a flag -unroll-verify-domtree; it verifies the domtree immediately
after we finish updating it. This is on by default for +Asserts builds.

Differential Revision: https://reviews.llvm.org/D28073



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292447 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-18 23:26:37 +00:00
Peter Collingbourne
1d08431d77 Cloning: Copy comdats when cloning globals.
Differential Revision: https://reviews.llvm.org/D28838

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292430 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-18 20:02:31 +00:00
Michael Kuperstein
517331b4f0 Fix up a comment. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292425 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-18 19:05:48 +00:00
Michael Kuperstein
c3a226d450 [LV] Allow reductions that have several uses outside the loop
We currently check whether a reduction has a single outside user. We don't
really need to require that - we just need to make sure a single value is
used externally. The number of external users of that value shouldn't actually
matter.

Differential Revision: https://reviews.llvm.org/D28830


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292424 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-18 19:02:52 +00:00
Eugene Zelenko
13bc67e541 [Target, Transforms] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292320 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-18 00:57:48 +00:00
Matt Arsenault
3bd79e8a80 SimplifyLibCalls: Remove checks for fabs
Use the intrinsic instead of emitting the libcall which
will be replaced by the intrinsic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292176 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-17 00:30:31 +00:00
Matt Arsenault
5276f9a934 SimplifyLibCalls: Replace fabs libcalls with intrinsics
Add missing fabs(fpext) optimzation that worked with the call,
and also fixes it creating a second fpext when there were multiple
uses.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292172 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-17 00:10:40 +00:00
Chandler Carruth
10dd00ced5 [PM] Introduce an analysis set used to preserve all analyses over
a function's CFG when that CFG is unchanged.

This allows transformation passes to simply claim they preserve the CFG
and analysis passes to check for the CFG being preserved to remove the
fanout of all analyses being listed in all passes.

I've gone through and removed or cleaned up as many of the comments
reminding us to do this as I could.

Differential Revision: https://reviews.llvm.org/D28627

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292054 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-15 06:32:49 +00:00
Eugene Zelenko
034cc87d1e [Transforms/Utils] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291983 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-14 00:32:38 +00:00
David L. Jones
b9565c5ed6 "Use" lambda captures which are otherwise only used in asserts. NFC
Summary:
The LLVM coding standards recommend "using" values that are only
needed by asserts:
http://llvm.org/docs/CodingStandards.html#assert-liberally

Without this change, LLVM cannot bootstrap with -Werror as the second
stage fails with this new warning:
https://reviews.llvm.org/rL291905

See also the previous fixes:
https://reviews.llvm.org/rL291916
https://reviews.llvm.org/rL291939
https://reviews.llvm.org/rL291940
https://reviews.llvm.org/rL291941

Reviewers: rsmith

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28695

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291957 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-13 21:02:41 +00:00
Robert Lougher
79af005177 [DebugInfo] Remove redundant check in SimplifyCFG; NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291813 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-12 21:11:09 +00:00
Robert Lougher
c61d8bcc07 [DebugInfo] DILocation variable declaration should be const; NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291787 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-12 18:33:49 +00:00
Florian Hahn
108d72a027 [loop-unroll] Properly populate LoopInfo for loops cloned in LoopUnrollRuntime.
Summary:
This fixes Transforms/LoopUnroll/runtime-loop3.ll which failed with
EXTENSIVE_DEBUG, because the cloned basic blocks were not added to the
correct sub-loops in LoopUnrollRuntime.cpp.


Reviewers: dexonsmith, mzolotukhin

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28482

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291619 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-10 23:43:35 +00:00
Florian Hahn
2fa5ad0ad4 [loop-unroll] Factor out code to update LoopInfo (NFC).
Move the code to update LoopInfo for cloned basic blocks to
addClonedBlockToLoopInfo, as suggested in 
https://reviews.llvm.org/D28482.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291614 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-10 23:24:54 +00:00
Michael Kuperstein
c7eb5df9be [LV] Don't panic when encountering the IV of an outer loop.
Bail out instead of asserting when we encounter this situation,
which can actually happen.

The reason the test uses the new PM is that the "bad" phi, incidentally, gets
cleaned up by LoopSimplify. But LICM can create this kind of phi and preserve
loop simplify form, so the cleanup has no chance to run.

This fixes PR31190.
We may want to solve this in a less conservative manner, since this phi is
actually uniform within the inner loop (or we may want LICM to output a cleaner
promotion to begin with).

Differential Revision: https://reviews.llvm.org/D28490


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291589 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-10 19:32:30 +00:00
Davide Italiano
b614cd308d [SimplifyLibCalls] Propagate fast math flags while optimizing pow().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291577 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-10 18:02:05 +00:00
Davide Italiano
3cb206f57f [SimplifyLibCalls] pow(x, -0.5) -> 1.0 / sqrt(x).
Differential Revision:  https://reviews.llvm.org/D28479

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291486 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-09 21:55:23 +00:00
Matt Arsenault
071eccb255 SimplifyLibCalls: Remove incorrect optimization of fabs
fabs(x * x) is not generally safe to assume x is positive if x is a NaN.
This is also less general than it could be, so this will be replaced
with a transformation on the intrinsic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291359 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-07 19:55:12 +00:00
Teresa Johnson
17b59bf192 [ThinLTO] Handle conflicting local names gracefully
Summary:
r285871 introduced an assert that was overly aggressive in the case
of a same-named local in different same-named files (in different
directories), where the source name and therefore the GUID ended up
the same because the files were compiled in their own directory without
any leading path. Change the handling in the promotion logic to get
the summary for the version in that module.

This also exposed an issue where we are not always importing the
right copy, which is a performance not correctness issue (because
the renaming is based on the module hash which must be different,
see the bug report for details). I will fix that as a follow-on.

Fixes PR31561.

Reviewers: mehdi_amini

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28411

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291304 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-06 23:38:41 +00:00
Teresa Johnson
f6f4d232fd [ThinLTO] Add parenthesis as per build warning
Fixes a warning about "||" and "&&" due to r291108.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291119 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-05 15:10:10 +00:00
Teresa Johnson
e4e6279a08 [ThinLTO] Subsume all importing checks into a single flag
Summary:
This adds a new summary flag NotEligibleToImport that subsumes
several existing flags (NoRename, HasInlineAsmMaybeReferencingInternal
and IsNotViableToInline). It also subsumes the checking of references
on the summary that was being done during the thin link by
eligibleForImport() for each candidate. It is much more efficient to
do that checking once during the per-module summary build and record
it in the summary.

Reviewers: mehdi_amini

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28169

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291108 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-05 14:32:16 +00:00
Robert Lougher
2698658e91 Reapply "[SimplifyCFG] In sinkLastInstruction correctly set debugloc of common inst"
This reapplies r289828 (reverted in r289833 as it broke the address sanitizer).  The
debugloc is now only set when the instruction is not a call, as this causes the
verifier to assert (the inliner requires an inlinable callsite to have a debug loc
if the caller and callee have debug info).

Original commit message:

Simplify CFG will try to sink the last instruction in a series of basic blocks,
creating a "common" instruction in the successor block (sinkLastInstruction).
When it does this, the debug location of the single instruction should be the
merged debug locations of the commoned instructions.

Original review: https://reviews.llvm.org/D27590


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290973 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-04 17:40:32 +00:00
Xin Tong
059fad8157 Make sure total loop body weight is preserved in loop peeling
Summary:
Regardless how the loop body weight is distributed, we should preserve
total loop body weight. i.e. we should have same weight reaching the body of the loop
or its duplicates in peeled and unpeeled case.

Reviewers: mkuper, davidxl, anemet

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28179

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290833 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-02 20:27:23 +00:00
Sanjay Patel
0e0f143f17 fix typo; NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290827 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-02 19:05:11 +00:00
Sanjay Patel
a8cf343942 [Inliner] remove unnecessary null checks from AddAlignmentAssumptions(); NFCI
We bail out on the 1st line if the assumption cache is not set, so there's
no need to check it after that.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290787 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-31 17:54:05 +00:00
Philip Reames
4194070c43 Add a comment for a todo in LoopUnroll post cleanup
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290769 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-30 22:10:19 +00:00
Chandler Carruth
2789d18739 [PM] Move the collection of call sites to a more appropriate place
inside of `InlineFunction`. Prior to this, call instructions are
specifically being rewritten and replaced within the inlined region,
invalidating some of the call sites.

Several of these regions are using the same technique to walk the
inlined region so this seems clearly safe up to this point.

I've also added a short circuit to the scan for call sites based on what
other code is doing.

With this, the most common crash I've found in the new inliner code is
fixed. I've turned it on for another test case that covers this
scenario.

I'll make my way through most of the other inliner test cases
just to get some easy coverage next.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290562 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-27 01:24:50 +00:00
Chandler Carruth
0b88030fbe [PM] Teach the always inliner in the new pass manager to support
removing fully-dead comdats without removing dead entries in comdats
with live members.

This factors the core logic out of the current inliner's internals to
a reusable utility and leverages that in both places. The factored out
code should also be (minorly) more efficient in cases where we have very
few dead functions or dead comdats to consider.

I've added a test case to cover this behavior of the always inliner.
This is the last significant bug in the new PM's always inliner I've
found (so far).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290557 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-26 23:43:27 +00:00
Bryant Wong
5b27f1a97f [MemorySSA] Define a restricted upward AccessList splice.
Differential Revision: https://reviews.llvm.org/D26661

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290527 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-25 23:34:07 +00:00
Adrian Prantl
f53a7ab5bb Refactor the DIExpression fragment query interface (NFC)
... so it becomes available to DIExpressionCursor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290322 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-22 05:27:12 +00:00
Haicheng Wu
036647c99a [LoopUnroll] Modify a comment to clarify the usage of TripCount. NFC.
Make it clear that TripCount is the upper bound of the iteration on which
control exits LatchBlock.

Differential Revision: https://reviews.llvm.org/D26675

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290199 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-20 20:23:48 +00:00
Chandler Carruth
54cffa1811 [PM] Provide an initial, minimal port of the inliner to the new pass manager.
This doesn't implement *every* feature of the existing inliner, but
tries to implement the most important ones for building a functional
optimization pipeline and beginning to sort out bugs, regressions, and
other problems.

Notable, but intentional omissions:
- No alloca merging support. Why? Because it isn't clear we want to do
  this at all. Active discussion and investigation is going on to remove
  it, so for simplicity I omitted it.
- No support for trying to iterate on "internally" devirtualized calls.
  Why? Because it adds what I suspect is inappropriate coupling for
  little or no benefit. We will have an outer iteration system that
  tracks devirtualization including that from function passes and
  iterates already. We should improve that rather than approximate it
  here.
- Optimization remarks. Why? Purely to make the patch smaller, no other
  reason at all.

The last one I'll probably work on almost immediately. But I wanted to
skip it in the initial patch to try to focus the change as much as
possible as there is already a lot of code moving around and both of
these *could* be skipped without really disrupting the core logic.

A summary of the different things happening here:

1) Adding the usual new PM class and rigging.

2) Fixing minor underlying assumptions in the inline cost analysis or
   inline logic that don't generally hold in the new PM world.

3) Adding the core pass logic which is in essence a loop over the calls
   in the nodes in the call graph. This is a bit duplicated from the old
   inliner, but only a handful of lines could realistically be shared.
   (I tried at first, and it really didn't help anything.) All told,
   this is only about 100 lines of code, and most of that is the
   mechanics of wiring up analyses from the new PM world.

4) Updating the LazyCallGraph (in the new PM) based on the *newly
   inlined* calls and references. This is very minimal because we cannot
   form cycles.

5) When inlining removes the last use of a function, eagerly nuking the
   body of the function so that any "one use remaining" inline cost
   heuristics are immediately refined, and queuing these functions to be
   completely deleted once inlining is complete and the call graph
   updated to reflect that they have become dead.

6) After all the inlining for a particular function, updating the
   LazyCallGraph and the CGSCC pass manager to reflect the
   function-local simplifications that are done immediately and
   internally by the inline utilties. These are the exact same
   fundamental set of CG updates done by arbitrary function passes.

7) Adding a bunch of test cases to specifically target CGSCC and other
   subtle aspects in the new PM world.

Many thanks to the careful review from Easwaran and Sanjoy and others!

Differential Revision: https://reviews.llvm.org/D24226

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290161 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-20 03:15:32 +00:00
Florian Hahn
c8f0c8614b [LoopVersioning] Require loop-simplify form for loop versioning.
Summary:
Requiring loop-simplify form for loop versioning ensures that the
runtime check block always dominates the exit block.
    
This patch closes #30958 (https://llvm.org/bugs/show_bug.cgi?id=30958).

Reviewers: silviu.baranga, hfinkel, anemet, ashutosh.nema

Subscribers: ashutosh.nema, mzolotukhin, efriedma, hfinkel, llvm-commits

Differential Revision: https://reviews.llvm.org/D27469

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290116 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-19 17:13:37 +00:00
Daniel Jasper
8de3a54f07 Revert @llvm.assume with operator bundles (r289755-r289757)
This creates non-linear behavior in the inliner (see more details in
r289755's commit thread).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290086 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-19 08:22:17 +00:00
Michael Kuperstein
569cd219c7 Preserve loop metadata when folding branches to a common destination.
Differential Revision: https://reviews.llvm.org/D27830


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289992 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-16 21:23:59 +00:00
Davide Italiano
236ad05ef8 [SimplifyLibCalls] Use a lambda. NFCI.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289911 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-16 02:28:38 +00:00
Davide Italiano
d956fc2438 [SimplifyLibCalls] Lower fls() to llvm.ctlz().
Differential Revision:  https://reviews.llvm.org/D14590

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289894 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-15 23:45:11 +00:00
Davide Italiano
30983dc098 [SimplifyLibCalls] Remove redundant folding logic for ffs().
Lowering to llvm.cttz() will result in constant folding anyway
if the argument to ffs is a constant. Pointed out by Eli for
fls() in D14590.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289888 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-15 23:11:00 +00:00
Andrea Di Biagio
84ecaa6c56 [SimplifyCFG] Merge debug locations when hoisting an instruction from a then/else branch. NFC.
Now that a new API to merge debug locations has been committed at r289661 (see
review D26256 for more details), we can use it to "improve" the code added by
revision r280995.

Instead of nulling the debugloc of a commoned instruction, we use the 'merged'
debug location. At the moment, this is just a no functional change since
function `DILocation::getMergedLocation()` is just a stub and would always
return a null location.

Differential Revision: https://reviews.llvm.org/D27804


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289862 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-15 20:01:26 +00:00
Robert Lougher
bdaef54463 Revert "[SimplifyCFG] In sinkLastInstruction correctly set debugloc of common inst"
Reverting as it is causing buildbot failures (address sanitizer).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289833 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-15 16:59:13 +00:00
Robert Lougher
9fc6de78fb [SimplifyCFG] In sinkLastInstruction correctly set debugloc of "common" inst
Simplify CFG will try to sink the last instruction in a series of basic blocks,
creating a "common" instruction in the successor block (sinkLastInstruction).
When it does this, the debug location of the single instruction should be the
merged debug locations of the commoned instructions.

Differential Revision: https://reviews.llvm.org/D27590


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289828 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-15 16:17:53 +00:00
Hal Finkel
bffeba468d Remove the AssumptionCache
After r289755, the AssumptionCache is no longer needed. Variables affected by
assumptions are now found by using the new operand-bundle-based scheme. This
new scheme is more computationally efficient, and also we need much less
code...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289756 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-15 03:02:15 +00:00
Stephan Bergmann
20a600c431 Replace APFloatBase static fltSemantics data members with getter functions
At least the plugin used by the LibreOffice build
(<https://wiki.documentfoundation.org/Development/Clang_plugins>) indirectly
uses those members (through inline functions in LLVM/Clang include files in turn
using them), but they are not exported by utils/extract_symbols.py on Windows,
and accessing data across DLL/EXE boundaries on Windows is generally
problematic.

Differential Revision: https://reviews.llvm.org/D26671

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289647 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-14 11:57:17 +00:00
Andrea Di Biagio
dbcb7adb03 [InlineFunction] Refactor code in function `fixupLineNumbers' as suggested by David in D27462. NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288901 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-07 12:01:45 +00:00
Andrea Di Biagio
0736f445e3 [InlineFunction] Do not propagate the callsite debug location to instructions inlined from functions with debug info.
When a function F is inlined, InlineFunction extends the debug location of every
instruction inlined from F by adding an InlinedAt.

However, if an instruction has a 'null' debug location, InlineFunction would
propagate the callsite debug location to it. This behavior existed since
revision 210459.

Revision 210459 was originally committed specifically to workaround the lack of
debug information for instructions inlined from intrinsic functions (which are
usually declared with attributes `__always_inline__, __nodebug__`).

The problem with revision 210459 is that it doesn't make any sort of distinction
between instructions inlined from a 'nodebug' function and instructions which
are inlined from a function built with debug info. This issue may lead to
incorrect stepping in the debugger.

This patch works under the assumption that a nodebug function does not have a
DISubprogram. When a function F is inlined into another function G,
InlineFunction checks if F has debug info associated with it.

For nodebug functions, the InlineFunction logic is unchanged (i.e. it would
still propagate the callsite debugloc to the inlined instructions). Otherwise,
InlineFunction no longer propagates the callsite debug location.

Differential Revision: https://reviews.llvm.org/D27462


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2016-12-07 10:37:26 +00:00
Adrian Prantl
460dd60c1a [DIExpression] Introduce a dedicated DW_OP_LLVM_fragment operation
so we can stop using DW_OP_bit_piece with the wrong semantics.

The entire back story can be found here:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20161114/405934.html

The gist is that in LLVM we've been misinterpreting DW_OP_bit_piece's
offset field to mean the offset into the source variable rather than
the offset into the location at the top the DWARF expression stack. In
order to be able to fix this in a subsequent patch, this patch
introduces a dedicated DW_OP_LLVM_fragment operation with the
semantics that we used to apply to DW_OP_bit_piece, which is what we
actually need while inside of LLVM. This patch is complete with a
bitcode upgrade for expressions using the old format. It does not yet
fix the DWARF backend to use DW_OP_bit_piece correctly.

Implementation note: We discussed several options for implementing
this, including reserving a dedicated field in DIExpression for the
fragment size and offset, but using an custom operator at the end of
the expression works just fine and is more efficient because we then
only pay for it when we need it.

Differential Revision: https://reviews.llvm.org/D27361
rdar://problem/29335809

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2016-12-05 18:04:47 +00:00
Michael Kuperstein
ceceabb371 Remove stale comment. NFC.
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2016-12-03 01:59:13 +00:00
Peter Collingbourne
a705e0edef IR: Move NumElements field from {Array,Vector}Type to SequentialType.
Now that PointerType is no longer a SequentialType, all SequentialTypes
have an associated number of elements, so we can move that information to
the base class, allowing for a number of simplifications.

Differential Revision: https://reviews.llvm.org/D27122

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2016-12-02 03:20:58 +00:00
Peter Collingbourne
06115803f9 IR: Change the gep_type_iterator API to avoid always exposing the "current" type.
Instead, expose whether the current type is an array or a struct, if an array
what the upper bound is, and if a struct the struct type itself. This is
in preparation for a later change which will make PointerType derive from
Type rather than SequentialType.

Differential Revision: https://reviews.llvm.org/D26594

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2016-12-02 02:24:42 +00:00
Teresa Johnson
7d2e3aa58e [ThinLTO] Stop importing constant global vars as copies in the backend
Summary:
We were doing an optimization in the ThinLTO backends of importing
constant unnamed_addr globals unconditionally as a local copy (regardless
of whether the thin link decided to import them). This should be done in
the thin link instead, so that resulting exported references are marked
and promoted appropriately, but will need a summary enhancement to mark
these variables as constant unnamed_addr.

The function import logic during the thin link was trying to handle
this proactively, by conservatively marking all values referenced in
the initializer lists of exported global variables as also exported.
However, this only handled values referenced directly from the
initializer list of an exported global variable. If the value is itself
a constant unnamed_addr variable, we could end up exporting its
references as well. This caused multiple issues. The first is that the
transitively exported references weren't promoted. Secondly, some could
not be promoted/renamed (e.g. they had a section or other constraint).
recursively, instead of just adding the first level of initializer list
references to the ExportList directly.

Remove this optimization and the associated handling in the function
import backend. SPEC measurements indicate we weren't getting much
from it in any case.

Fixes PR31052.

Reviewers: mehdi_amini

Subscribers: krasin, llvm-commits

Differential Revision: https://reviews.llvm.org/D26880

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2016-12-02 01:02:30 +00:00