Commit Graph

297 Commits

Author SHA1 Message Date
Jessica Paquette faea2d3130 Revert "Enable MachineOutliner by default under -Oz for AArch64"
It failed an Asan test on a bot:

http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/21543/steps/check-llvm%20asan/logs/stdio

Fixing that before recommitting.

llvm-svn: 338136
2018-07-27 17:25:38 +00:00
Jessica Paquette d4229b985c Enable MachineOutliner by default under -Oz for AArch64
This patch enables the MachineOutliner by default in AArch64 under -Oz.

The MachineOutliner offers around a 4.5% improvement on the current -Oz code
size improvements.

We have done work into improving the debuggability of outlined code, so that
users of -Oz won't be surprised by the optimization. We have also been executing
the LLVM test suite and common external tests such as the SPEC suites
continuously with no issue. The outliner has a low compile-time overhead of
roughly 1%. At this point, the outliner would be a really good addition to the
-Oz pass pipeline!

llvm-svn: 338133
2018-07-27 16:44:42 +00:00
Jessica Paquette 69f517df27 [MachineOutliner][NFC] Move target frame info into OutlinedFunction
Just some gardening here.

Similar to how we moved call information into Candidates, this moves outlined
frame information into OutlinedFunction. This allows us to remove
TargetCostInfo entirely.

Anywhere where we returned a TargetCostInfo struct, we now return an
OutlinedFunction. This establishes OutlinedFunctions as more of a general
repeated sequence, and Candidates as occurrences of those repeated sequences.

llvm-svn: 337848
2018-07-24 20:13:10 +00:00
Jessica Paquette fca55129b1 [MachineOutliner][NFC] Make Candidates own their call information
Before this, TCI contained all the call information for each Candidate.

This moves that information onto the Candidates. As a result, each Candidate
can now supply how it ought to be called. Thus, Candidates will be able to,
say, call the same function in cheaper ways when possible. This also removes
that information from TCI, since it's no longer used there.

A follow-up patch for the AArch64 outliner will demonstrate this.

llvm-svn: 337840
2018-07-24 17:42:11 +00:00
Yvan Roux a96a04558d [MachineOutliner] Assert that Liveness tracking is accurate (NFC)
The checking is done deeper inside MachineBasicBlock, but this will
hopefully help to find issues when porting the machine outliner to a
target where Liveness tracking is broken (like ARM).

Differential Revision: https://reviews.llvm.org/D49023

llvm-svn: 336481
2018-07-07 08:02:19 +00:00
Yvan Roux eaececf5e0 [MachineOutliner] Fix typo in getOutliningCandidateInfo function name
getOutlininingCandidateInfo -> getOutliningCandidateInfo

Differential Revision: https://reviews.llvm.org/D48867

llvm-svn: 336285
2018-07-04 15:37:08 +00:00
Jessica Paquette f472f6159a [MachineOutliner] Don't outline sequences where x16/x17/nzcv are live across
It isn't safe to outline sequences of instructions where x16/x17/nzcv live
across the sequence.

This teaches the outliner to check whether or not a specific canidate has
x16/x17/nzcv live across it and discard the candidate in the case that that is
true.

https://bugs.llvm.org/show_bug.cgi?id=37573
https://reviews.llvm.org/D47655

llvm-svn: 335758
2018-06-27 17:43:27 +00:00
Jessica Paquette 32de26d432 [MachineOutliner] NFC: Remove insertOutlinerPrologue, rename insertOutlinerEpilogue
insertOutlinerPrologue was not used by any target, and prologue-esque code was
beginning to appear in insertOutlinerEpilogue. Refactor that into one function,
buildOutlinedFrame.

This just removes insertOutlinerPrologue and renames insertOutlinerEpilogue.

llvm-svn: 335076
2018-06-19 21:14:48 +00:00
Jessica Paquette aa087327ce [MachineOutliner] NFC - Move intermediate data structures to MachineOutliner.h
This is setting up to fix bug 37573 cleanly.

This moves data structures that are technically both used in some way by the
target and the general-purpose outlining algorithm into MachineOutliner.h. In
particular, the `Candidate` class is of importance.

Before, the outliner passed the locations of `Candidates` to the target, which
would then make some decisions about the prospective outlined function. This
change allows us to just pass `Candidates` along to the target. This will allow
the target to discard `Candidates` that would be considered unsafe before cost
calculation. Thus, we will be able to remove the unsafe candidates described in
the bug without resorting to torching the entire prospective function.

Also, as a side-effect, it makes the outliner a bit cleaner.

https://bugs.llvm.org/show_bug.cgi?id=37573

llvm-svn: 333952
2018-06-04 21:14:16 +00:00
Eli Friedman 785acce51d Delete unused variable from r333015.
(The assertion suppressed the unused variable warning on
Release+Asserts builds, so I didn't notice.)

llvm-svn: 333018
2018-05-22 19:38:07 +00:00
Eli Friedman 042dc9e092 [MachineOutliner] Add "thunk" outlining for AArch64.
When we're outlining a sequence that ends in a call, we can save up to
three instructions in the outlined function by turning the call into
a tail-call. I refer to this as thunk outlining because the resulting
outlined function looks like a thunk; suggestions welcome for a better
name.

In addition to making the outlined function shorter, thunk outlining
allows outlining calls which would otherwise be illegal to outline:
we don't need to save/restore LR, so we don't need to prove anything
about the stack access patterns of the callee.

To make this work effectively, I also added
MachineOutlinerInstrType::LegalTerminator to the generic MachineOutliner
code; this allows treating an arbitrary instruction as a terminator in
the suffix tree.

Differential Revision: https://reviews.llvm.org/D47173

llvm-svn: 333015
2018-05-22 19:11:06 +00:00
Eli Friedman 4081a57af7 [MachineOutliner] Count savings from outlining in bytes.
Counting the number of instructions is both unintuitive and inaccurate.
On AArch64, this only affects the generated remarks and certain rare
pseudo-instructions, but it will have a bigger impact on other targets.

Differential Revision: https://reviews.llvm.org/D46921

llvm-svn: 332685
2018-05-18 01:52:16 +00:00
Eli Friedman ddbf6d6514 [MachineOutliner] Don't outline instructions that modify SP.
This breaks the code which saves and restores LR, so we can't outline
without doing something more complicated for stack adjustment.

Found by inspection; we get lucky in most cases because getMemOpInfo
only handles STRWpost, not any other pre/post-increment forms. But it
hits a couple of artificial testcases in the tree.

Differential Revision: https://reviews.llvm.org/D46920

llvm-svn: 332529
2018-05-16 21:20:16 +00:00
Eli Friedman 02709bcb78 [MachineOutliner] Don't save/restore LR for tail calls.
The cost computation assumes we do this correctly, but the actual
lowering was wrong.

Differential Revision: https://reviews.llvm.org/D46923

llvm-svn: 332514
2018-05-16 19:49:01 +00:00
Shiva Chen 801bf7ebbe [DebugInfo] Examine all uses of isDebugValue() for debug instructions.
Because we create a new kind of debug instruction, DBG_LABEL, we need to
check all passes which use isDebugValue() to check MachineInstr is debug
instruction or not. When expelling debug instructions, we should expel
both DBG_VALUE and DBG_LABEL. So, I create a new function,
isDebugInstr(), in MachineInstr to check whether the MachineInstr is
debug instruction or not.

This patch has no new test case. I have run regression test and there is
no difference in regression test.

Differential Revision: https://reviews.llvm.org/D45342

Patch by Hsiangkai Wang.

llvm-svn: 331844
2018-05-09 02:42:00 +00:00
Adrian Prantl 5f8f34e459 Remove \brief commands from doxygen comments.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

  for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46290

llvm-svn: 331272
2018-05-01 15:54:18 +00:00
Jessica Paquette 0b6724917a [MachineOutliner] Add defs to calls + don't track liveness on outlined functions
This commit makes it so that if you outline a def of some register, then the
call instruction created by the outliner actually reflects that the register
is defined by the call. It also makes it so that outlined functions don't
have the TracksLiveness property.

Outlined calls shouldn't break liveness assumptions that someone might make.

This also un-XFAILs the noredzone test, and updates the calls test.

llvm-svn: 331095
2018-04-27 23:36:35 +00:00
Eli Friedman da018e5687 [MachineOutliner] Don't outline from functions with a section marking.
The program might have unusual expectations for functions; for example,
the Linux kernel's build system warns if it finds references from .text
to .init.data.

I'm not sure this is something we actually want to make any guarantees
about (there isn't any explicit rule that would disallow outlining
in this case), but we might want to be conservative anyway.

Differential Revision: https://reviews.llvm.org/D46091

llvm-svn: 331007
2018-04-27 00:21:34 +00:00
Jessica Paquette 4f56428de1 [MachineOutliner] Check for explicit uses of LR/W30 in MI operands
Before, the outliner would grab ADRPs that used LR/W30. This patch fixes
that by checking for explicit uses of those registers before the special-casing
for ADRPs.

This also adds a test that ensures that those sorts of ADRPs won't be outlined.

llvm-svn: 330783
2018-04-24 22:38:15 +00:00
Jessica Paquette 2e5ada5c81 [MachineOutliner] Change B instruction for tail calls to TCRETURNdi
First off, this is more correct than having the B. Second off, this was making
a bot upset. This fixes that.

Update the test to include -verify-machineinstrs as well to prevent stuff like
this slipping by non debug/assert builds in the future.

llvm-svn: 330459
2018-04-20 18:03:21 +00:00
Jessica Paquette 642f6c61a3 [MachineOutliner] Keep track of fns that use a redzone in AArch64FunctionInfo
This patch adds a hasRedZone() function to AArch64MachineFunctionInfo. It
returns true if the function is known to use a redzone, false if it is known
to not use a redzone, and no value otherwise.

This removes the requirement to pass -mno-red-zone when outlining for AArch64.

https://reviews.llvm.org/D45189

llvm-svn: 329120
2018-04-03 21:56:10 +00:00
Jessica Paquette 4aa14dbcc2 [MachineOutliner] Simplify call outlining + require valid callee save info for call outlining
This commit simplifies the call outlining logic by removing references to the
Function associated with the callee. To do this, it requires that valid
callee save info is available to the outliner.

llvm-svn: 328719
2018-03-28 17:52:31 +00:00
Jessica Paquette 2519ee7081 [MachineOutliner] AArch64: Don't outline ADRPs with un-outlinable operands
If an ADRP appears with, say, a CPI operand, we shouldn't outline it.

This moves the check for unsafe operands so that it occurs before the special-case
for ADRPs. Also add a test for outlining ADRPs.

llvm-svn: 328674
2018-03-27 22:23:48 +00:00
Jessica Paquette 563548d8f3 [MachineOutliner] AArch64: Emit CFI instructions when outlining calls
When outlining calls, the outliner needs to update CFI to ensure that, say,
exception handling works. This commit adds that functionality and adds a test
just for call outlining.

Call outlining stuff in machine-outliner.mir should be moved into
machine-outliner-calls.mir in a later commit.

llvm-svn: 327917
2018-03-19 22:48:40 +00:00
Jessica Paquette b3e7dc9144 [MachineOutliner] Make KILLs invisible
At the point the outliner runs, KILLs don't impact anything, but they're still
considered unique instructions. This commit makes them invisible like
DebugValues so that they can still be outlined without impacting outlining
decisions.

llvm-svn: 327760
2018-03-16 22:53:34 +00:00
Evandro Menezes 1515e859c6 [AArch64] Adjust the cost model for Exynos M3
Increase the number of cheap as move cases of register reset.

llvm-svn: 327661
2018-03-15 20:31:13 +00:00
Evandro Menezes b5f12090fc [AArch64] Refactor stand alone methods (NFC)
Make stand alone methods in AArch64InstrInfo static.

llvm-svn: 324745
2018-02-09 16:14:41 +00:00
Evandro Menezes 07c78eeeef [AArch64] Add new target feature to handle cheap as move for Exynos
This feature enables special handling of cheap as move in the existing
custom handling specifically for Exynos processors.

Differential revision: https://reviews.llvm.org/D42387

llvm-svn: 323774
2018-01-30 15:40:22 +00:00
Evandro Menezes 9f9daa1f14 [AArch64] Add pipeline model for Exynos M3
Add the scheduling and cost model for Exynos M3.

Differential revision: https://reviews.llvm.org/D42387

llvm-svn: 323773
2018-01-30 15:40:16 +00:00
Oliver Stannard a9d2e004d2 [AArch64] Generate the CASP instruction for 128-bit cmpxchg
The Large System Extension added an atomic compare-and-swap instruction
that operates on a pair of 64-bit registers, which we can use to
implement a 128-bit cmpxchg.

Because i128 is not a legal type for AArch64 we have to do all of the
instruction selection in C++, and the instruction requires even/odd
register pairs, so we have to wrap it in REG_SEQUENCE and EXTRACT_SUBREG
nodes. This is very similar to what we do for 64-bit cmpxchg in the ARM
backend.

Differential revision: https://reviews.llvm.org/D42104

llvm-svn: 323634
2018-01-29 09:18:37 +00:00
Jessica Paquette 757e120379 [MachineOutliner] Move hasAddressTaken check to MachineOutliner.cpp
*Mostly* NFC. Still updating the test though just for completeness.

This moves the hasAddressTaken check to MachineOutliner.cpp and replaces it
with a per-basic block test rather than a per-function test. The old test was
too conservative and was preventing functions in C programs from being
outlined even though they were safe to outline.

This was mostly a problem in C sources.

llvm-svn: 322425
2018-01-13 00:42:28 +00:00
Jessica Paquette c191f1097c [MachineOutliner] Outline ADRPs
ADRP instructions weren't being outlined because they're PC-relative and thus
fail the LR checks. This patch adds a special case for ADRPs to
getOutliningType to make sure that ADRPs can be outlined and updates the MIR
test.

llvm-svn: 322207
2018-01-10 18:49:57 +00:00
Jessica Paquette 3291e7353e [MachineOutliner] AArch64: Handle instrs that use SP and will never need fixups
This commit does two things. Firstly, it adds a collection of flags which can
be passed along to the target to encode information about the MBB that an
instruction lives in to the outliner.

Second, it adds some of those flags to the AArch64 outliner in order to add
more stack instructions to the list of legal instructions that are handled
by the outliner. The two flags added check if

- There are calls in the MachineBasicBlock containing the instruction
- The link register is available in the entire block

If the link register is available and there are no calls, then a stack
instruction can always be outlined without fixups, regardless of what it is,
since in this case, the outliner will never modify the stack to create a
call or outlined frame.

The motivation for doing this was checking which instructions are most often
missed by the outliner. Instructions like, say

%sp<def> = ADDXri %sp, 32, 0; flags: FrameDestroy

are very common, but cannot be outlined in the case that the outliner might
modify the stack. This commit allows us to outline instructions like this.
  

llvm-svn: 322048
2018-01-09 00:26:18 +00:00
Matthew Simpson 9439f54902 [AArch64] Change order of candidate FMLS patterns
r319980 added new patterns to the machine combiner for transforming (fsub (fmul
x y) z) into (fmla (fneg z) x y). That is, fsub's where the first source
operand is an fmul are transformed. We previously only matched the case where
the second source operand of an fsub was an fmul, transforming (fsub z (fmul x
y)) into (fmls z x y). Now, if we have an fsub where both source operands are
fmuls, both of the above patterns are applicable.

However, the order in which we add the patterns to the list of candidates
determines the transformation that takes place, since only the first pattern
that matches will be used. This patch changes the order these two patterns are
added to the list of candidates such that we prefer the case where the second
source operand is an fmul (the fmls case), rather than the other one (the
fmla/fneg case). When both source operands are fmuls, this ordering results in
fewer instructions.

Differential Revision: https://reviews.llvm.org/D41587

llvm-svn: 321491
2017-12-27 15:25:01 +00:00
Jessica Paquette 8565d3af84 [MachineOutliner][NFC] Gardening: use std::any_of instead of bool + loop
River Riddle suggested to use std::any_of instead of the bool + loop thing on
r320229. This commit does that.

llvm-svn: 321028
2017-12-18 21:44:52 +00:00
Jessica Paquette 02c124d644 [MachineOutliner] Recommit r320229
LR was undefined entering outlined functions that contain calls. This made the
machine verifier unhappy when expensive checks were enabled. This fixes that.

llvm-svn: 321014
2017-12-18 19:33:21 +00:00
Matthias Braun f1caa2833f MachineFunction: Return reference from getFunction(); NFC
The Function can never be nullptr so we can return a reference.

llvm-svn: 320884
2017-12-15 22:22:58 +00:00
Francis Visoiu Mistrih 0b5bdceabf [CodeGen] Print stack object references as %(fixed-)stack.0 in both MIR and debug output
Work towards the unification of MIR and debug output by printing
`%stack.0` instead of `<fi#0>`, and `%fixed-stack.0` instead of
`<fi#-4>` (supposing there are 4 fixed stack objects).

Only debug syntax is affected.

Differential Revision: https://reviews.llvm.org/D41027

llvm-svn: 320827
2017-12-15 16:33:45 +00:00
Galina Kistanova 9dee3f0a97 Reverted r320229. It broke tests on builder llvm-clang-x86_64-expensive-checks-win.
llvm-svn: 320588
2017-12-13 15:26:27 +00:00
Jessica Paquette a249c4f513 [MachineOutliner] Outline calls
The outliner previously would never outline calls. Calls are pretty common in
files, so it makes sense to outline them. In fact, in the LLVM test suite, if
you count the number of instructions that the outliner misses when you outline
calls vs when you don't, it turns out that, on average, around 6% of the
instructions encountered are calls. So, if we outline calls, we can find more
candidates, and thus save some more space.

This commit adds that functionality and updates the mir test to reflect that.

llvm-svn: 320229
2017-12-09 00:43:49 +00:00
Jessica Paquette 59948666fb [MachineOutliner] Fix offset overflow check
The offset overflow check before was incorrect. It would always give the
correct result, but it was comparing the SCALED potential fixed-up offset
against an UNSCALED minimum/maximum. As a result, the outliner was missing a
bunch of frame setup/destroy instructions that ought to have been safe to
outline. This fixes that, and adds an instruction to the .mir test that
failed the old test.
  

llvm-svn: 320090
2017-12-07 21:51:43 +00:00
Francis Visoiu Mistrih a8a83d150f [CodeGen] Use MachineOperand::print in the MIRPrinter for MO_Register.
Work towards the unification of MIR and debug output by refactoring the
interfaces.

For MachineOperand::print, keep a simple version that can be easily called
from `dump()`, and a more complex one which will be called from both the
MIRPrinter and MachineInstr::print.

Add extra checks inside MachineOperand for detached operands (operands
with getParent() == nullptr).

https://reviews.llvm.org/D40836

* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/kill: ([^ ]+) ([^ ]+)<def> ([^ ]+)/kill: \1 def \2 \3/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/kill: ([^ ]+) ([^ ]+) ([^ ]+)<def>/kill: \1 \2 def \3/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/kill: def ([^ ]+) ([^ ]+) ([^ ]+)<def>/kill: def \1 \2 def \3/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/<def>//g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<kill>/killed \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-use,kill>/implicit killed \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<dead>/dead \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<def[ ]*,[ ]*dead>/dead \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-def[ ]*,[ ]*dead>/implicit-def dead \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-def>/implicit-def \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-use>/implicit \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<internal>/internal \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<undef>/undef \1/g'

llvm-svn: 320022
2017-12-07 10:40:31 +00:00
Florian Hahn 5d6a4e43ba [AArch64] Add patterns to replace fsub fmul with fma fneg.
Summary:
This patch adds MachineCombiner patterns for transforming
(fsub (fmul x y) z) into (fma x y (fneg z)). This has a lower
latency on micro architectures where fneg is cheap.

Patch based on work by George Steed.

Reviewers: rengolin, joelkevinjones, joel_k_jones, evandro, efriedma

Reviewed By: evandro

Subscribers: aemerson, javed.absar, llvm-commits, kristof.beyls

Differential Revision: https://reviews.llvm.org/D40306

llvm-svn: 319980
2017-12-06 22:48:36 +00:00
Francis Visoiu Mistrih 93ef145862 [CodeGen] Print "%vreg0" as "%0" in both MIR and debug output
As part of the unification of the debug format and the MIR format, avoid
printing "vreg" for virtual registers (which is one of the current MIR
possibilities).

Basically:

* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E "s/%vreg([0-9]+)/%\1/g"
* grep -nr '%vreg' . and fix if needed
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E "s/ vreg([0-9]+)/ %\1/g"
* grep -nr 'vreg[0-9]\+' . and fix if needed

Differential Revision: https://reviews.llvm.org/D40420

llvm-svn: 319427
2017-11-30 12:12:19 +00:00
Francis Visoiu Mistrih 9d7bb0cb40 [CodeGen] Print register names in lowercase in both MIR and debug output
As part of the unification of the debug format and the MIR format,
always print registers as lowercase.

* Only debug printing is affected. It now follows MIR.

Differential Revision: https://reviews.llvm.org/D40417

llvm-svn: 319187
2017-11-28 17:15:09 +00:00
David Blaikie b3bde2ea50 Fix a bunch more layering of CodeGen headers that are in Target
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).

llvm-svn: 318490
2017-11-17 01:07:10 +00:00
Tim Northover 350a87eaf1 AArch64: account for possible frame index operand in compares.
If the address of a local is used in a comparison, AArch64 can fold the
address-calculation into the comparison via "adds". Unfortunately, a couple of
places (both hit in this one test) are not ready to deal with that yet and just
assume the first source operand is a register.

llvm-svn: 316035
2017-10-17 21:43:52 +00:00
Jessica Paquette 13593843f6 [MachineOutliner] Disable outlining from LinkOnceODRs by default
Say you have two identical linkonceodr functions, one in M1 and one in M2.
Say that the outliner outlines A,B,C from one function, and D,E,F from another
function (where letters are instructions). Now those functions are not
identical, and cannot be deduped. Locally to M1 and M2, these outlining
choices would be good-- to the whole program, however, this might not be true!

To mitigate this, this commit makes it so that the outliner sees linkonceodr
functions as unsafe to outline from. It also adds a flag,
-enable-linkonceodr-outlining, which allows the user to specify that they
want to outline from such functions when they know what they're doing.

Changing this handles most code size regressions in the test suite caused by
competing with linker dedupe. It also doesn't have a huge impact on the code
size improvements from the outliner. There are 6 tests that regress > 5% from
outlining WITH linkonceodrs to outlining WITHOUT linkonceodrs. Overall, most
tests either improve or are not impacted.

Not outlined vs outlined without linkonceodrs:
https://hastebin.com/raw/qeguxavuda

Not outlined vs outlined with linkonceodrs:
https://hastebin.com/raw/edepoqoqic

Outlined with linkonceodrs vs outlined without linkonceodrs:
https://hastebin.com/raw/awiqifiheb

Numbers generated using compare.py with -m size.__text. Tests run for AArch64
with -Oz -mllvm -enable-machine-outliner -mno-red-zone.

llvm-svn: 315136
2017-10-07 00:16:34 +00:00
Jessica Paquette 4cf187b5b4 [MachineOutliner] AArch64: Avoid saving + restoring LR if possible
This commit allows the outliner to avoid saving and restoring the link register
on AArch64 when it is dead within an entire class of candidates.

This introduces changes to the way the outliner interfaces with the target.
For example, the target now interfaces with the outliner using a
MachineOutlinerInfo struct rather than by using getOutliningCallOverhead and
getOutliningFrameOverhead.

This also improves several comments on the outliner's cost model.

https://reviews.llvm.org/D36721

llvm-svn: 314341
2017-09-27 20:47:39 +00:00
Evandro Menezes 91650ef061 [AArch64] Adjust the cost model for Exynos M1 and M2
Refine the model of loads and stores using the register offset addressing
modes.

llvm-svn: 313554
2017-09-18 19:00:36 +00:00
Evandro Menezes 9cd1bd7a83 [AArch64] Adjust the cost model for Exynos M1 and M2
Fix formatting in the predicate function AArch64InstrInfo::isExynosShiftLeftFast().

llvm-svn: 313553
2017-09-18 19:00:31 +00:00
Stanislav Mekhanoshin 7fe9a5d9b4 Allow target to decide when to cluster loads/stores in misched
MachineScheduler when clustering loads or stores checks if base
pointers point to the same memory. This check is done through
comparison of base registers of two memory instructions. This
works fine when instructions have separate offset operand. If
they require a full calculated pointer such instructions can
never be clustered according to such logic.

Changed shouldClusterMemOps to accept base registers as well and
let it decide what to do about it.

Differential Revision: https://reviews.llvm.org/D37698

llvm-svn: 313208
2017-09-13 22:20:47 +00:00
Evandro Menezes 509516d200 [AArch64] Adjust the cost model for Exynos M1 and M2
Add new predicate to more accurately model the cost of arithmetic and
logical operations shifted left.

Differential revision: https://reviews.llvm.org/D37151

llvm-svn: 311943
2017-08-28 22:51:32 +00:00
Sjoerd Meijer b0eb5fb317 [AArch64] Add FMOVH0: materialize 0 using zero register for f16 values
Instead of loading 0 from a constant pool, it's of course much better to
materialize it using an fmov and the zero register.

Thanks to Ahmed Bougacha for the suggestion.

Differential Revision: https://reviews.llvm.org/D37102

llvm-svn: 311662
2017-08-24 14:47:06 +00:00
Jessica Paquette 6315d2d21d [MachineOutliner] Add RegState::Define to LDRXpost in insertOutlinedCall
This fixes a MachineVerifier failure in machine-outliner.mir. Not explicitly
adding RegState::Define to the LR argument makes it unhappy because an explicit
definition is marked as a use.

Build failure:
http://lab.llvm.org:8080/green/job/clang-stage1-cmake-RA-expensive/7496/testReport/junit/LLVM/CodeGen_AArch64/machine_outliner_mir/

llvm-svn: 310671
2017-08-10 23:11:24 +00:00
Jessica Paquette d36945bf3a [MachineOutliner] Ensure AArch64 outliner doesn't mess with W30 or LR
Before, the outliner would mark all instructions that read from/modify LR as
illegal. This doesn't handle W30, which overlaps with LR. This shouldn't be
outlined.

This commit fixes that by making modifiesRegister() and readsRegister() look at
W30 + take in a TRI argument. This makes sure that modifiesRegister() and
readsRegister() won't outline either of W30 and LR.

https://reviews.llvm.org/D36435

llvm-svn: 310422
2017-08-08 21:51:26 +00:00
Jessica Paquette d87f54493d [MachineOutliner] NFC: Change IsTailCall to a call class + frame class
This commit

- Removes IsTailCall and replaces it with a target-defined unsigned
- Refactors getOutliningCallOverhead and getOutliningFrameOverhead so that they don't use IsTailCall
- Adds a call class + frame class classification to OutlinedFunction and Candidate respectively

This accomplishes a couple things.

Firstly, we don't need the notion of *tail call* in the general outlining algorithm.

Secondly, we now can have different "outlining classes" for each candidate within a set of candidates.
This will make it easy to add new ways to outline sequences for certain targets and dynamically choose
an appropriate cost model for a sequence depending on the context that that sequence lives in.

Ultimately, this should get us closer to being able to do something like, say avoid saving the link
register when outlining AArch64 instructions.

llvm-svn: 309475
2017-07-29 02:55:46 +00:00
Jessica Paquette 809d708b8a [MachineOutliner] NFC: Split up getOutliningBenefit
This is some more cleanup in preparation for some actual
functional changes. This splits getOutliningBenefit into
two cost functions: getOutliningCallOverhead and
getOutliningFrameOverhead. These functions return the
number of instructions that would be required to call
a specific function and the number of instructions
that would be required to construct a frame for a
specific funtion. The actual outlining benefit logic
is moved into the outliner, which calls these functions.

The goal of refactoring getOutliningBenefit is to:

- Get us closer to getting rid of the IsTailCall flag

- Further split up "target-specific" things and
"general algorithm" things

llvm-svn: 309356
2017-07-28 03:21:58 +00:00
Adrian Prantl 8f4b353ee1 Remove unused function from AArch64 backend (NFC)
llvm-svn: 309336
2017-07-27 23:52:06 +00:00
Geoff Berry b1e8714af9 [AArch64][Falkor] Avoid HW prefetcher tag collisions (step 1)
Summary:
This patch is the first step in reducing HW prefetcher instruction tag
collisions in inner loops for Falkor.  It adds a pass that annotates IR
loads with metadata to indicate that they are known to be strided loads,
and adds a target lowering hook that translates this metadata to a
target-specific MachineMemOperand flag.

A follow on change will use this MachineMemOperand flag to re-write
instructions to reduce tag collisions.

Reviewers: mcrosier, t.p.northover

Subscribers: aemerson, rengolin, mgorny, javed.absar, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D34963

llvm-svn: 308059
2017-07-14 21:44:12 +00:00
Geoff Berry 6748abe24d [MIR] Add support for printing and parsing target MMO flags
Summary: Add target hooks for printing and parsing target MMO flags.
Targets may override getSerializableMachineMemOperandTargetFlags() to
return a mapping from string to flag value for target MMO values that
should be serialized/parsed in MIR output.

Add implementation of this hook for AArch64 SuppressPair MMO flag.

Reviewers: bogner, hfinkel, qcolombet, MatzeB

Subscribers: mcrosier, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D34962

llvm-svn: 307877
2017-07-13 02:28:54 +00:00
Joel Jones 7466ccfc59 Doxygen formatting. NFCI
llvm-svn: 307597
2017-07-10 22:11:50 +00:00
Simon Pilgrim 8b4dc53326 [AArch64] Fix -Wimplicit-fallthrough warnings. NFCI.
llvm-svn: 307393
2017-07-07 13:03:28 +00:00
Joel Jones aff09bf052 Doxygen formatting. NFCI
llvm-svn: 307263
2017-07-06 14:17:36 +00:00
Chad Rosier 6db9ff64a8 [AArch64] Prefer Bcc to CBZ/CBNZ/TBZ/TBNZ when NZCV flags can be set for "free".
This patch contains a pass that transforms CBZ/CBNZ/TBZ/TBNZ instructions into a
conditional branch (Bcc), when the NZCV flags can be set for "free". This is
preferred on targets that have more flexibility when scheduling Bcc
instructions as compared to CBZ/CBNZ/TBZ/TBNZ (assuming all other variables are
equal). This can reduce register pressure and is also the default behavior for
GCC.

A few examples:

 add w8, w0, w1  -> cmn w0, w1             ; CMN is an alias of ADDS.
 cbz w8, .LBB_2  -> b.eq .LBB0_2           ; single def/use of w8 removed.

 add w8, w0, w1  -> adds w8, w0, w1        ; w8 has multiple uses.
 cbz w8, .LBB1_2 -> b.eq .LBB1_2

 sub w8, w0, w1       -> subs w8, w0, w1   ; w8 has multiple uses.
 tbz w8, #31, .LBB6_2 -> b.ge .LBB6_2

In looking at all current sub-target machine descriptions, this transformation
appears to be either positive or neutral.

Differential Revision: https://reviews.llvm.org/D34220.

llvm-svn: 306144
2017-06-23 19:20:12 +00:00
Chandler Carruth 6bda14b313 Sort the remaining #include lines in include/... and lib/....
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.

I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.

This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.

Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).

llvm-svn: 304787
2017-06-06 11:49:48 +00:00
Geoff Berry d6ac96f953 [AArch64][Falkor] Refine sched details for LSLfast/ASRfast.
llvm-svn: 303682
2017-05-23 19:57:45 +00:00
Chad Rosier 8b12a03215 Fix an improperly placed curly bracket. NFC.
llvm-svn: 303165
2017-05-16 12:43:23 +00:00
Chad Rosier aeffffdb44 [AArch64][MachineCombine] Fold FNMUL+FSUB -> FNMADD.
Differential Revision: http://reviews.llvm.org/D33101.

llvm-svn: 302822
2017-05-11 20:07:24 +00:00
Krzysztof Parzyszek 44e25f37ae Move size and alignment information of regclass to TargetRegisterInfo
1. RegisterClass::getSize() is split into two functions:
   - TargetRegisterInfo::getRegSizeInBits(const TargetRegisterClass &RC) const;
   - TargetRegisterInfo::getSpillSize(const TargetRegisterClass &RC) const;
2. RegisterClass::getAlignment() is replaced by:
   - TargetRegisterInfo::getSpillAlignment(const TargetRegisterClass &RC) const;

This will allow making those values depend on subtarget features in the
future.

Differential Revision: https://reviews.llvm.org/D31783

llvm-svn: 301221
2017-04-24 18:55:33 +00:00
Hans Wennborg 9b9a5358dd Re-commit r301040 "X86: Don't emit zero-byte functions on Windows"
In addition to the original commit, tighten the condition for when to
pad empty functions to COFF Windows.  This avoids running into problems
when targeting e.g. Win32 AMDGPU, which caused test failures when this
was committed initially.

llvm-svn: 301047
2017-04-21 21:48:41 +00:00
Hans Wennborg 04593000d8 Revert r301040 "X86: Don't emit zero-byte functions on Windows"
This broke almost all bots. Reverting while fixing.

llvm-svn: 301041
2017-04-21 21:10:37 +00:00
Hans Wennborg cb3e810714 X86: Don't emit zero-byte functions on Windows
Empty functions can lead to duplicate entries in the Guard CF Function
Table of a binary due to multiple functions sharing the same RVA,
causing the kernel to refuse to load that binary.

We had a terrific bug due to this in Chromium.

It turns out we were already doing this for Mach-O in certain
situations. This patch expands the code for that in
AsmPrinter::EmitFunctionBody() and renames
TargetInstrInfo::getNoopForMachoTarget() to simply getNoop() since it
seems it was used for not just Mach-O anyway.

Differential Revision: https://reviews.llvm.org/D32330

llvm-svn: 301040
2017-04-21 20:58:12 +00:00
Balaram Makam b4419f9d30 [AArch64] Refine Falkor Machine Model - Part 3
This concludes the refinements to Falkor Machine Model.
  It includes SchedPredicates for immediate zero and LSL Fast.
  Forwarding logic is also modeled for vector multiply and
  accumulate only.

llvm-svn: 299810
2017-04-08 03:30:15 +00:00
Jessica Paquette eac8633d6d [Outliner] Revert r298734.
When I tested r298734, I thought that red zones were enabled by default like in
X86. Since red zones are behind a flag on AArch64 the testing wasn't true.

llvm-svn: 298747
2017-03-24 23:00:21 +00:00
Jessica Paquette 167af85ec7 [Outliner] Remove no red zone requirment for AArch64
AArch64 doesn't require -mno-red-zone; stack fixups are sufficient here. This was
unnecessarily copied over from the X86 target.

(You can now outline with red zones! Yay!)

Removing the requirement passes all Single/MultiSource tests.

llvm-svn: 298734
2017-03-24 20:47:59 +00:00
Jessica Paquette 02cbfb2926 [Outliner] ACTUALLY remove the errs output
I don't know how to type. This fixes the last commit which would have made all
of the overflows legal, and kept the screaming.

llvm-svn: 298263
2017-03-20 16:25:04 +00:00
Jessica Paquette 5d59a4ee19 [Outliner] Remove output for offset range check
Forgot to remove some output before committing last time. (Instruction fixups
don't actually overflow anywhere in the test suite so far, so I missed it).

To prevent the outliner from screaming "Overflow!" in the event that that
does happen, this commit removes that output.

llvm-svn: 298260
2017-03-20 15:51:45 +00:00
Jessica Paquette ea8cc09be0 [Outliner] Add outliner for AArch64
This commit adds the necessary target hooks for outlining in AArch64. It also
refactors the switch statement used in `getMemOpBaseRegImmOfsWidth` into a
more general function, `getMemOpInfo`. This allows the outliner to share that
code without copying and pasting it.

The AArch64 outliner can be run using -mllvm -enable-machine-outliner, as with
the X86-64 outliner.

The test for this pass verifies that the outliner does, in fact outline
functions, fixes up the stack accesses properly, and can correctly generate a
tail call. In the future, this test should be replaced with a MIR test, so that
we can properly test immediate offset overflows in fixed-up instructions.

llvm-svn: 298162
2017-03-17 22:26:55 +00:00
Matthias Braun e959544517 TargetInstrInfo: Provide default implementation of isTailCall().
In fact this default implementation should be the only implementation,
keep it virtual for now to accomodate targets that don't model flags
correctly.

Differential Revision: https://reviews.llvm.org/D30747

llvm-svn: 297980
2017-03-16 20:02:30 +00:00
Azharuddin Mohammed 473b75c3d5 Remove CRC32 instructions from AArch64InstrInfo::hasShiftedReg
Summary:
A53 scheduler causes an assertion failure on all CRC instructions:
include/llvm/CodeGen/MachineInstr.h:280: const llvm::MachineOperand
&llvm::MachineInstr::getOperand(unsigned int) const: Assertion `i <
getNumOperands() && "getOperand() out of range!"' failed.

The case statements corresponding to CRC instructions are incorrect and should
be removed.

Also adding a testcase while on this.

Reviewers: t.p.northover, javed.absar, apazos, rengolin

Reviewed By: rengolin

Subscribers: evandro, aemerson, llvm-commits, rengolin

Differential Revision: https://reviews.llvm.org/D30274

llvm-svn: 297582
2017-03-12 14:02:32 +00:00
Evandro Menezes 94edf02923 [CodeGen] Move MacroFusion to the target
This patch moves the class for scheduling adjacent instructions,
MacroFusion, to the target.

In AArch64, it also expands the fusion to all instructions pairs in a
scheduling block, beyond just among the predecessors of the branch at the
end.

Differential revision: https://reviews.llvm.org/D28489

llvm-svn: 293737
2017-02-01 02:54:34 +00:00
Serge Rogatch bc2d34394d [XRay][AArch64] More staging for tail call support in XRay on AArch64 - in LLVM
Summary:
This patch prepares more for tail call support in XRay. Until the logging part supports tail calls, this is just staging, so it seems LLVM part is mostly ready with this patch.
Related: https://reviews.llvm.org/D28948 (compiler-rt)

Reviewers: dberris, rengolin

Reviewed By: dberris

Subscribers: llvm-commits, iid_iunknown, aemerson

Differential Revision: https://reviews.llvm.org/D28947

llvm-svn: 293080
2017-01-25 20:21:49 +00:00
Evandro Menezes 7784cacd91 [AArch64] Rename 'no-quad-ldst-pairs' to 'slow-paired-128'
In order to follow the pattern of the existing 'slow-misaligned-128store'
option, rename the option 'no-quad-ldst-pairs' to 'slow-paired-128'.

llvm-svn: 292954
2017-01-24 17:34:31 +00:00
Evandro Menezes 7960b2e19a [AArch64] Generate literals by the little end
ARM seems to prefer that long literals be formed from their little end in
order to promote the fusion of the instrs pairs MOV/MOVK and MOVK/MOVK on
Cortex A57 and others (v.  "Cortex A57 Software Optimisation Guide", section
4.14).

Differential revision: https://reviews.llvm.org/D28697

llvm-svn: 292422
2017-01-18 18:57:08 +00:00
Diana Picus 116bbab4e4 [CodeGen] Rename MachineInstrBuilder::addOperand. NFC
Rename from addOperand to just add, to match the other method that has been
added to MachineInstrBuilder for adding more than just 1 operand.

See https://reviews.llvm.org/D28057 for the whole discussion.

Differential Revision: https://reviews.llvm.org/D28556

llvm-svn: 291891
2017-01-13 09:58:52 +00:00
Eugene Zelenko 049b017538 [AArch64, Lanai] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).
llvm-svn: 291197
2017-01-06 00:30:53 +00:00
Logan Chien ce542eefe3 Code cleanup: Remove tab indents.
llvm-svn: 291193
2017-01-05 23:41:33 +00:00
Geoff Berry d46b6e8096 [AArch64] Fold some filled/spilled subreg COPYs
Summary:
Extend AArch64 foldMemoryOperandImpl() to handle folding spills of
subreg COPYs with read-undef defs like:

  %vreg0:sub_32<def,read-undef> = COPY %WZR; GPR64:%vreg0

by widening the spilled physical source reg and generating:

  STRXui %XZR <fi#0>

as well as folding fills of similar COPYs like:

  %vreg0:sub_32<def,read-undef> = COPY %vreg1; GPR64:%vreg0, GPR32:%vreg1

by generating:

  %vreg0:sub_32<def,read-undef> = LDRWui <fi#0>

Reviewers: MatzeB, qcolombet

Subscribers: aemerson, rengolin, mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D27425

llvm-svn: 291180
2017-01-05 21:51:42 +00:00
Geoff Berry 7ffce7be0c [AArch64] Fold more spilled/refilled COPYs.
Summary:
Make AArch64InstrInfo::foldMemoryOperandImpl more general by folding all
full COPYs between register classes of the same size that are either
spilled or refilled.

Reviewers: MatzeB, qcolombet

Subscribers: aemerson, rengolin, mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D27271

llvm-svn: 288439
2016-12-01 23:43:55 +00:00
Geoff Berry 7c078fc035 [AArch64] Fold spills of COPY of WZR/XZR
Summary:
In AArch64InstrInfo::foldMemoryOperandImpl, catch more cases where the
COPY being spilled is copying from WZR/XZR, but the source register is
not in the COPY destination register's regclass.

For example, when spilling:

  %vreg0 = COPY %XZR ; %vreg0:GPR64common

without this change, the code in TargetInstrInfo::foldMemoryOperand()
and canFoldCopy() that normally handles cases like this would fail to
optimize since %XZR is not in GPR64common.  So the spill code generated
would be:

  %vreg0 = COPY %XZR
  STR %vreg

instead of the new code generated:

  STR %XZR

Reviewers: qcolombet, MatzeB

Subscribers: mcrosier, aemerson, t.p.northover, llvm-commits, rengolin

Differential Revision: https://reviews.llvm.org/D26976

llvm-svn: 288176
2016-11-29 18:28:32 +00:00
Matthias Braun 115efcd3d1 MachineScheduler: Export function to construct "default" scheduler.
This makes the createGenericSchedLive() function that constructs the
default scheduler available for the public API. This should help when
you want to get a scheduler and the default list of DAG mutations.

This also shrinks the list of default DAG mutations:
{Load|Store}ClusterDAGMutation and MacroFusionDAGMutation are no longer
added by default. Targets can easily add them if they need them. It also
makes it easier for targets to add alternative/custom macrofusion or
clustering mutations while staying with the default
createGenericSchedLive(). It also saves the callback back and forth in
TargetInstrInfo::enableClusterLoads()/enableClusterStores().

Differential Revision: https://reviews.llvm.org/D26986

llvm-svn: 288057
2016-11-28 20:11:54 +00:00
Abderrazek Zaafrani 9f382f53d1 Test commit
llvm-svn: 284832
2016-10-21 15:24:08 +00:00
Matt Arsenault 0a3ea89e85 AArch64: Move remaining target specific BranchRelaxation bits to TII
llvm-svn: 283458
2016-10-06 15:38:09 +00:00
Matthias Braun 46a5238682 AArch64: Macrofusion: Split features, add missing combinations.
AArch64InstrInfo::shouldScheduleAdjacent() determines whether two
instruction can benefit from macroop fusion on apple CPUs. The list
turned out to be incomplete:
- the "rr" variants of the instructions were missing
- even the "rs" variants can have shift value == 0 and behave like the
  "rr" variants

This also splits the MacropFusion target feature into
ArithmeticBccFusion and ArithmeticCbzFusion.

Differential Revision: https://reviews.llvm.org/D25142

llvm-svn: 283243
2016-10-04 19:28:21 +00:00
Evandro Menezes 19b2aed308 [AArch64] Support for FP FMA when -ffp-contract=fast
Currently, the machine combiner can proceed matching when -ffast-math is on.
It should also match when only -ffp-contract=fast is specified as was the
case before when DAGCombiner was doing the job.

Patch by: Abderrazek Zaafrani <a.zaafrani@samsung.com>.

Differential Revision: https://reviews.llvm.org/D24366

llvm-svn: 281649
2016-09-15 19:55:23 +00:00
Matt Arsenault 1b9fc8ed65 Finish renaming remaining analyzeBranch functions
llvm-svn: 281535
2016-09-14 20:43:16 +00:00
Matt Arsenault e8e0f5cac6 Make analyzeBranch family of instruction names consistent
analyzeBranch was renamed to use lowercase first, rename
the related set to match.

llvm-svn: 281506
2016-09-14 17:24:15 +00:00
Matt Arsenault a2b036e88b AArch64: Use TTI branch functions in branch relaxation
The main change is to return the code size from
InsertBranch/RemoveBranch.

Patch mostly by Tim Northover

llvm-svn: 281505
2016-09-14 17:23:48 +00:00
Diana Picus 4b97288184 [AArch64] Support stackmap/patchpoint in getInstSizeInBytes
We currently return 4 for stackmaps and patchpoints, which is very optimistic
and can in rare cases cause the branch relaxation pass to fail to relax certain
branches.

This patch causes getInstSizeInBytes to return a pessimistic estimate of the
size as the number of bytes requested in the stackmap/patchpoint. In the future,
we could provide a more accurate estimate by sharing some of the logic in
AArch64::LowerSTACKMAP/PATCHPOINT.

Fixes part of https://llvm.org/bugs/show_bug.cgi?id=28750

Differential Revision: https://reviews.llvm.org/D24073

llvm-svn: 281301
2016-09-13 07:45:17 +00:00