Commit Graph

3501 Commits

Author SHA1 Message Date
Reid Kleckner
741d8a21d3 Correct PrivateLinkage for COFF
- Use storage class C_STAT for 'PrivateLinkage' The storage class for
  PrivateLinkage should equal to the Internal Linkage.

- Set 'PrivateGlobalPrefix' from "L" to ".L" for MM_WinCOFF (includes
  x86_64) MM_WinCOFF has empty GlobalPrefix '\0' so PrivateGlobalPrefix
  "L" may conflict to the normal symbol name starting with 'L'.

Based on a patch by Han Sangjin! Manually updated test cases.

llvm-svn: 284096
2016-10-13 00:55:24 +00:00
Konstantin Zhuravlyov
081385a74e [DAGCombiner] Do not remove the load of stored values when optimizations are disabled
This combiner breaks debug experience and should not be run when optimizations are disabled.

For example:
  int main() {
    int j = 0;
    j += 2;
    if (j == 2)
      return 0;
    return 5;
  }
When debugging this code compiled in /O0, it should be valid to break at line "j+=2;" and edit the value of j. It should change the return value of the function.

Differential Revision: https://reviews.llvm.org/D19268

llvm-svn: 284014
2016-10-12 13:44:24 +00:00
Kyle Butt
0846e56e63 Codegen: Tail-duplicate during placement.
The tail duplication pass uses an assumed layout when making duplication
decisions. This is fine, but passes up duplication opportunities that
may arise when blocks are outlined. Because we want the updated CFG to
affect subsequent placement decisions, this change must occur during
placement.

In order to achieve this goal, TailDuplicationPass is split into a
utility class, TailDuplicator, and the pass itself. The pass delegates
nearly everything to the TailDuplicator object, except for looping over
the blocks in a function. This allows the same code to be used for tail
duplication in both places.

This change, in concert with outlining optional branches, allows
triangle shaped code to perform much better, esepecially when the
taken/untaken branches are correlated, as it creates a second spine when
the tests are small enough.

Issue from previous rollback fixed, and a new test was added for that
case as well. Issue was worklist/scheduling/taildup issue in layout.

Issue from 2nd rollback fixed, with 2 additional tests. Issue was
tail merging/loop info/tail-duplication causing issue with loops that share
a header block.

Issue with early tail-duplication of blocks that branch to a fallthrough
predecessor fixed with test case: tail-dup-branch-to-fallthrough.ll

Differential revision: https://reviews.llvm.org/D18226

llvm-svn: 283934
2016-10-11 20:36:43 +00:00
Oliver Stannard
50a74393c2 [ARM] Fix registers clobbered by SjLj EH on soft-float targets
Currently, the Int_eh_sjlj_dispatchsetup intrinsic is marked as
clobbering all registers, including floating-point registers that may
not be present on the target. This is technically true, as we could get
linked against code that does use the FP registers, but that will not
actually work, as the soft-float code cannot save and restore the FP
registers. SjLj exception handling can only work correctly if either all
or none of the code is built for a target with FP registers. Therefore,
we can assume that, when Int_eh_sjlj_dispatchsetup is compiled for a
soft-float target, it is only going to be linked against other
soft-float code, and so only clobbers the general-purpose registers.
This allows us to check that no non-savable registers are clobbered when
generating the prologue/epilogue.

Differential Revision: https://reviews.llvm.org/D25180

llvm-svn: 283866
2016-10-11 10:06:59 +00:00
Daniel Jasper
0c42dc4784 Revert "Codegen: Tail-duplicate during placement."
This reverts commit r283842.

test/CodeGen/X86/tail-dup-repeat.ll causes and llc crash with our
internal testing. I'll share a link with you.

llvm-svn: 283857
2016-10-11 07:36:11 +00:00
Kyle Butt
ae068a320c Codegen: Tail-duplicate during placement.
The tail duplication pass uses an assumed layout when making duplication
decisions. This is fine, but passes up duplication opportunities that
may arise when blocks are outlined. Because we want the updated CFG to
affect subsequent placement decisions, this change must occur during
placement.

In order to achieve this goal, TailDuplicationPass is split into a
utility class, TailDuplicator, and the pass itself. The pass delegates
nearly everything to the TailDuplicator object, except for looping over
the blocks in a function. This allows the same code to be used for tail
duplication in both places.

This change, in concert with outlining optional branches, allows
triangle shaped code to perform much better, esepecially when the
taken/untaken branches are correlated, as it creates a second spine when
the tests are small enough.

Issue from previous rollback fixed, and a new test was added for that
case as well. Issue was worklist/scheduling/taildup issue in layout.

Issue from 2nd rollback fixed, with 2 additional tests. Issue was
tail merging/loop info/tail-duplication causing issue with loops that share
a header block.

Issue with early tail-duplication of blocks that branch to a fallthrough
predecessor fixed with test case: tail-dup-branch-to-fallthrough.ll

Differential revision: https://reviews.llvm.org/D18226

llvm-svn: 283842
2016-10-11 01:20:33 +00:00
Alexandros Lamprineas
20e9ddba73 [ARM] Fix invalid VLDM/VSTM access when targeting Big Endian with NEON
The instructions VLDM/VSTM can only access word-aligned memory
locations and produce alignment fault if the condition is not met.

The compiler currently generates VLDM/VSTM for v2f64 load/store
regardless the alignment of the memory access. Instead, if a v2f64
load/store is not word-aligned, the compiler should generate
VLD1/VST1. For each non double-word-aligned VLD1/VST1, a VREV
instruction should be generated when targeting Big Endian.

Differential Revision: https://reviews.llvm.org/D25281

llvm-svn: 283763
2016-10-10 16:01:54 +00:00
Kyle Butt
2facd194a2 Revert "Codegen: Tail-duplicate during placement."
This reverts commit 71c312652c10f1855b28d06697c08d47e7a243e4.

llvm-svn: 283647
2016-10-08 01:47:05 +00:00
Kyle Butt
37e676d857 Codegen: Tail-duplicate during placement.
The tail duplication pass uses an assumed layout when making duplication
decisions. This is fine, but passes up duplication opportunities that
may arise when blocks are outlined. Because we want the updated CFG to
affect subsequent placement decisions, this change must occur during
placement.

In order to achieve this goal, TailDuplicationPass is split into a
utility class, TailDuplicator, and the pass itself. The pass delegates
nearly everything to the TailDuplicator object, except for looping over
the blocks in a function. This allows the same code to be used for tail
duplication in both places.

This change, in concert with outlining optional branches, allows
triangle shaped code to perform much better, esepecially when the
taken/untaken branches are correlated, as it creates a second spine when
the tests are small enough.

Issue from previous rollback fixed, and a new test was added for that
case as well. Issue was worklist/scheduling/taildup issue in layout.

Issue from 2nd rollback fixed, with 2 additional tests. Issue was
tail merging/loop info/tail-duplication causing issue with loops that share
a header block.

Differential revision: https://reviews.llvm.org/D18226

llvm-svn: 283619
2016-10-07 22:33:20 +00:00
Arnold Schwaighofer
3f25658143 swifterror: Don't compute swifterror vregs during instruction selection
The code used llvm basic block predecessors to decided where to insert phi
nodes. Instruction selection can and will liberally insert new machine basic
block predecessors. There is not a guaranteed one-to-one mapping from pred.
llvm basic blocks and machine basic blocks.

Therefore the current approach does not work as it assumes we can mark
predecessor machine basic block as needing a copy, and needs to know the set of
all predecessor machine basic blocks to decide when to insert phis.

Instead of computing the swifterror vregs as we select instructions, propagate
them at the end of instruction selection when the MBB CFG is complete.

When an instruction needs a swifterror vreg and we don't know the value yet,
generate a new vreg and remember this "upward exposed" use, and reconcile this
at the end of instruction selection.

This will only happen if the target supports promoting swifterror parameters to
registers and the swifterror attribute is used.

rdar://28300923

llvm-svn: 283617
2016-10-07 22:06:55 +00:00
Martin Storsjo
04864f45b2 [ARM] Reapply: Use __rt_div functions for divrem on Windows
Reapplying r283383 after revert in r283442. The additional fix
is a getting rid of a stray space in a function name, in the
refactoring part of the commit.

This avoids falling back to calling out to the GCC rem functions
(__moddi3, __umoddi3) when targeting Windows.

The __rt_div functions have flipped the two arguments compared
to the __aeabi_divmod functions. To match MSVC, we emit a
check for division by zero before actually calling the library
function (even if the library function itself also might do
the same check).

Not all calls to __rt_div functions for division are currently
merged with calls to the same function with the same parameters
for the remainder. This is more wasteful than a div + mls as before,
but avoids calls to __moddi3.

Differential Revision: https://reviews.llvm.org/D25332

llvm-svn: 283550
2016-10-07 13:28:53 +00:00
Javed Absar
fb4b6e8db9 [ARM]: Add Cortex-R52 target to LLVM
This patch adds Cortex-R52, the new ARM real-time processor, to LLVM. 
Cortex-R52 implements the ARMv8-R architecture.

llvm-svn: 283542
2016-10-07 12:06:40 +00:00
Diana Picus
6341e46cd1 Revert "[ARM] Use __rt_div functions for divrem on Windows"
This reverts commit r283383 because it broke some of the bots:
undefined reference to ` __aeabi_uldivmod'

It affected (at least) clang-cmake-armv7-a15-selfhost,
clang-cmake-armv7-a15-selfhost and clang-native-arm-lnt.

llvm-svn: 283442
2016-10-06 11:24:29 +00:00
James Molloy
6215fad0e9 [ARM] Constant pool promotion - fix alignment calculation
Global variables are GlobalValues, so they have explicit alignment. Querying
DataLayout for the alignment was incorrect.

Testcase added.

llvm-svn: 283423
2016-10-06 07:56:00 +00:00
James Molloy
78561c4917 [ARM] Improve testcase for r283323
We can work around a shortcoming of FileCheck by using {{\[}} to match a square
bracket before a [[ sequence.

Thanks to Eli Friedman for the heads up!

llvm-svn: 283422
2016-10-06 07:44:05 +00:00
Martin Storsjo
f997759aef [ARM] Use __rt_div functions for divrem on Windows
This avoids falling back to calling out to the GCC rem functions
(__moddi3, __umoddi3) when targeting Windows.

The __rt_div functions have flipped the two arguments compared
to the __aeabi_divmod functions. To match MSVC, we emit a
check for division by zero before actually calling the library
function (even if the library function itself also might do
the same check).

Not all calls to __rt_div functions for division are currently
merged with calls to the same function with the same parameters
for the remainder. This is more wasteful than a div + mls as before,
but avoids calls to __moddi3.

Differential Revision: https://reviews.llvm.org/D24076

llvm-svn: 283383
2016-10-05 21:08:02 +00:00
James Molloy
b7de497cb9 [Thumb] Don't try and emit LDRH/LDRB from the constant pool
This is not a valid encoding - these instructions cannot do PC-relative addressing.

The underlying problem here is of whitelist in ARMISelDAGToDAG that unwraps ARMISD::Wrappers during addressing-mode selection. This didn't realise TargetConstantPool was actually possible, so didn't handle it.

llvm-svn: 283323
2016-10-05 14:52:13 +00:00
Kyle Butt
25ac35d822 Revert "Codegen: Tail-duplicate during placement."
This reverts commit 062ace9764953e9769142c1099281a345f9b6bdc.

Issue with loop info and block removal revealed by polly.
I have a fix for this issue already in another patch, I'll re-roll this
together with that fix, and a test case.

llvm-svn: 283292
2016-10-05 01:39:29 +00:00
Kyle Butt
adabac2d57 Codegen: Tail-duplicate during placement.
The tail duplication pass uses an assumed layout when making duplication
decisions. This is fine, but passes up duplication opportunities that
may arise when blocks are outlined. Because we want the updated CFG to
affect subsequent placement decisions, this change must occur during
placement.

In order to achieve this goal, TailDuplicationPass is split into a
utility class, TailDuplicator, and the pass itself. The pass delegates
nearly everything to the TailDuplicator object, except for looping over
the blocks in a function. This allows the same code to be used for tail
duplication in both places.

This change, in concert with outlining optional branches, allows
triangle shaped code to perform much better, esepecially when the
taken/untaken branches are correlated, as it creates a second spine when
the tests are small enough.

Issue from previous rollback fixed, and a new test was added for that
case as well.

Differential revision: https://reviews.llvm.org/D18226

llvm-svn: 283274
2016-10-04 23:54:18 +00:00
Kyle Butt
3ffb8529bc Revert "Codegen: Tail-duplicate during placement."
This reverts commit ff234efbe23528e4f4c80c78057b920a51f434b2.

Causing crashes on aarch64 build.

llvm-svn: 283172
2016-10-04 00:38:23 +00:00
Kyle Butt
396bfdd707 Codegen: Tail-duplicate during placement.
The tail duplication pass uses an assumed layout when making duplication
decisions. This is fine, but passes up duplication opportunities that
may arise when blocks are outlined. Because we want the updated CFG to
affect subsequent placement decisions, this change must occur during
placement.

In order to achieve this goal, TailDuplicationPass is split into a
utility class, TailDuplicator, and the pass itself. The pass delegates
nearly everything to the TailDuplicator object, except for looping over
the blocks in a function. This allows the same code to be used for tail
duplication in both places.

This change, in concert with outlining optional branches, allows
triangle shaped code to perform much better, esepecially when the
taken/untaken branches are correlated, as it creates a second spine when
the tests are small enough.

llvm-svn: 283164
2016-10-04 00:00:09 +00:00
Sjoerd Meijer
4dbe73c1ed [ARM] Code size optimisation to lower udiv+urem to udiv+mls instead of a
library call to __aeabi_uidivmod. This is an improved implementation of
r280808, see also D24133, that got reverted because isel was stuck in a loop.
That was caused by the optimisation incorrectly triggering on i64 ints, which
shouldn't happen because there is no 64bit hwdiv support; that put isel's type
legalization and this optimisation in a loop. A native ARM compiler and testing
now shows that this is fixed.

Patch mostly by Pablo Barrio.

Differential Revision: https://reviews.llvm.org/D25077

llvm-svn: 283098
2016-10-03 10:12:32 +00:00
Adrian Prantl
7f5866c227 Teach LiveDebugValues about lexical scopes.
This addresses PR26055 LiveDebugValues is very slow.

Contrary to the old LiveDebugVariables pass LiveDebugValues currently
doesn't look at the lexical scopes before inserting a DBG_VALUE
intrinsic. This means that we often propagate DBG_VALUEs much further
down than necessary. This is especially noticeable in large C++
functions with many inlined method calls that all use the same
"this"-pointer.

For example, in the following code it makes no sense to propagate the
inlined variable a from the first inlined call to f() into any of the
subsequent basic blocks, because the variable will always be out of
scope:

void sink(int a);
void __attribute((always_inline)) f(int a) { sink(a); }
void foo(int i) {
   f(i);
   if (i)
     f(i);
   f(i);
}

This patch reuses the LexicalScopes infrastructure we have for
LiveDebugVariables to take this into account.

The effect on compile time and memory consumption is quite noticeable:
I tested a benchmark that is a large C++ source with an enormous
amount of inlined "this"-pointers that would previously eat >24GiB
(most of them for DBG_VALUE intrinsics) and whose compile time was
dominated by LiveDebugValues. With this patch applied the memory
consumption is 1GiB and 1.7% of the time is spent in LiveDebugValues.

https://reviews.llvm.org/D24994
Thanks to Daniel Berlin and Keith Walker for reviewing!

llvm-svn: 282611
2016-09-28 17:51:14 +00:00
Nirav Dave
e524f50882 Revert "In visitSTORE, always use FindBetterChain, rather than only when UseAA is enabled."
This reverts commit r282600 due to test failues with MCJIT

llvm-svn: 282604
2016-09-28 16:37:50 +00:00
Nirav Dave
e17e055b75 In visitSTORE, always use FindBetterChain, rather than only when UseAA is enabled.
Simplify Consecutive Merge Store Candidate Search

  Now that address aliasing is much less conservative, push through
  simplified store merging search which only checks for parallel stores
  through the chain subgraph. This is cleaner as the separation of
  non-interfering loads/stores from the store-merging logic.

  Whem merging stores, search up the chain through a single load, and
  finds all possible stores by looking down from through a load and a
  TokenFactor to all stores visited. This improves the quality of the
  output SelectionDAG and generally the output CodeGen (with some
  exceptions).

  Additional Minor Changes:

    1. Finishes removing unused AliasLoad code
    2. Unifies the the chain aggregation in the merged stores across
       code paths
    3. Re-add the Store node to the worklist after calling
       SimplifyDemandedBits.
    4. Increase GatherAllAliasesMaxDepth from 6 to 18. That number is
       arbitrary, but seemed sufficient to not cause regressions in
       tests.

  This finishes the change Matt Arsenault started in r246307 and
  jyknight's original patch.

  Many tests required some changes as memory operations are now
  reorderable. Some tests relying on the order were changed to use
  volatile memory operations

  Noteworthy tests:

    CodeGen/AArch64/argument-blocks.ll -
      It's not entirely clear what the test_varargs_stackalign test is
      supposed to be asserting, but the new code looks right.

    CodeGen/AArch64/arm64-memset-inline.lli -
    CodeGen/AArch64/arm64-stur.ll -
    CodeGen/ARM/memset-inline.ll -
      The backend now generates *worse* code due to store merging
      succeeding, as we do do a 16-byte constant-zero store efficiently.

    CodeGen/AArch64/merge-store.ll -
      Improved, but there still seems to be an extraneous vector insert
      from an element to itself?

    CodeGen/PowerPC/ppc64-align-long-double.ll -
      Worse code emitted in this case, due to the improved store->load
      forwarding.

    CodeGen/X86/dag-merge-fast-accesses.ll -
    CodeGen/X86/MergeConsecutiveStores.ll -
    CodeGen/X86/stores-merging.ll -
    CodeGen/Mips/load-store-left-right.ll -
      Restored correct merging of non-aligned stores

    CodeGen/AMDGPU/promote-alloca-stored-pointer-value.ll -
      Improved. Correctly merges buffer_store_dword calls

    CodeGen/AMDGPU/si-triv-disjoint-mem-access.ll -
      Improved. Sidesteps loading a stored value and merges two stores

    CodeGen/X86/pr18023.ll -
      This test has been removed, as it was asserting incorrect
      behavior. Non-volatile stores *CAN* be moved past volatile loads,
      and now are.

    CodeGen/X86/vector-idiv.ll -
    CodeGen/X86/vector-lzcnt-128.ll -
      It's basically impossible to tell what these tests are actually
      testing. But, looks like the code got better due to the memory
      operations being recognized as non-aliasing.

    CodeGen/X86/win32-eh.ll -
      Both loads of the securitycookie are now merged.

    CodeGen/AMDGPU/vgpr-spill-emergency-stack-slot-compute.ll -
      This test appears to work but no longer exhibits the spill
      behavior.

Reviewers: arsenm, hfinkel, tstellarAMD, nhaehnle, jyknight

Subscribers: wdng, nhaehnle, nemanjai, arsenm, weimingz, niravd, RKSimon, aemerson, qcolombet, resistor, tstellarAMD, t.p.northover, spatel

Differential Revision: https://reviews.llvm.org/D14834

llvm-svn: 282600
2016-09-28 15:50:43 +00:00
Keith Walker
83ebef5db3 Propagate DBG_VALUE entries when there are unvisited predecessors
Variables are sometimes missing their debug location information in
blocks in which the variables should be available. This would occur
when one or more predecessor blocks had not yet been visited by the
routine which propagated the information from predecessor blocks.

This is addressed by only considering predecessor blocks which have
already been visited.

The solution to this problem was suggested by Daniel Berlin on the
LLVM developer mailing list.

Differential Revision: https://reviews.llvm.org/D24927

llvm-svn: 282506
2016-09-27 16:46:07 +00:00
James Molloy
9abb2fa5bb [ARM] Promote small global constants to constant pools
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:

      ldr r0, .CPI0
      bl printf
      bx lr
    .CPI0: &format_string
    format_string: .asciz "hello, world!\n"

We can emit:

      adr r0, .CPI0
      bl printf
      bx lr
    .CPI0: .asciz "hello, world!\n"

This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).

This recommit contains fixes for a nasty bug related to fast-isel fallback - because
fast-isel doesn't know about this optimization, if it runs and emits references to
a string that we inline (because fast-isel fell back to SDAG) we will end up
with an inlined string and also an out-of-line string, and we won't emit the
out-of-line string, causing backend failures.

It also contains fixes for emitting .text relocations which made the sanitizer
bots unhappy.

llvm-svn: 282387
2016-09-26 07:26:24 +00:00
Matthias Braun
1acb55e67c ScheduleDAG: Match enum names when printing sdep kinds
It is less confusing to have the same names in the debug print as the
enum members.

llvm-svn: 282273
2016-09-23 18:28:31 +00:00
James Molloy
85124c76fc Revert "[ARM] Promote small global constants to constant pools"
This reverts commit r282241. It caused http://lab.llvm.org:8011/builders/clang-native-arm-lnt/builds/19882.

llvm-svn: 282249
2016-09-23 13:35:43 +00:00
James Molloy
1ce54d6be2 [ARM] Promote small global constants to constant pools
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:

      ldr r0, .CPI0
      bl printf
      bx lr
    .CPI0: &format_string
    format_string: .asciz "hello, world!\n"

We can emit:

      adr r0, .CPI0
      bl printf
      bx lr
    .CPI0: .asciz "hello, world!\n"

This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).

This recommit contains fixes for a nasty bug related to fast-isel fallback - because
fast-isel doesn't know about this optimization, if it runs and emits references to
a string that we inline (because fast-isel fell back to SDAG) we will end up
with an inlined string and also an out-of-line string, and we won't emit the
out-of-line string, causing backend failures.

It also contains fixes for emitting .text relocations which made the sanitizer
bots unhappy.

llvm-svn: 282241
2016-09-23 12:15:58 +00:00
Arnold Schwaighofer
de2490d0dc Disable tail calls if there is an swifterror argument
ISel does not handle them correctly yet i.e we crash trying to emit tail call
code.

radar://28407842

llvm-svn: 282088
2016-09-21 16:53:36 +00:00
Nico Weber
903859c0e4 Revert r281715, it caused PR30475
llvm-svn: 282076
2016-09-21 15:33:24 +00:00
Tim Northover
eaee28b5ca ARM: check alignment before transforming ldr -> ldm (or similar).
ldm and stm instructions always require 4-byte alignment on the pointer, but we
weren't checking this before trying to reduce code-size by replacing a
post-indexed load/store with them. Unfortunately, we were also dropping this
incormation in DAG ISel too, but that's easy enough to fix.

llvm-svn: 281893
2016-09-19 09:11:09 +00:00
Dean Michael Berris
4640154446 [XRay] ARM 32-bit no-Thumb support in LLVM
This is a port of XRay to ARM 32-bit, without Thumb support yet. The XRay instrumentation support is moving up to AsmPrinter.
This is one of 3 commits to different repositories of XRay ARM port. The other 2 are:

https://reviews.llvm.org/D23932 (Clang test)
https://reviews.llvm.org/D23933 (compiler-rt)

Differential Revision: https://reviews.llvm.org/D23931

llvm-svn: 281878
2016-09-19 00:54:35 +00:00
Sjoerd Meijer
227825346e Reverting r281719, this is causing buildbot failures and timeouts again.
llvm-svn: 281722
2016-09-16 13:16:52 +00:00
Sjoerd Meijer
23385c87a4 This is an attempt to reapply r280808: [ARM] Lower UDIV+UREM to UDIV+MLS
(and the same for SREM)

This was causing buildbot failures earlier (time outs in the LNT suite).
However, we haven't been able to reproduce this and are suspecting this
was caused by another (reverted) patch.

llvm-svn: 281719
2016-09-16 12:10:09 +00:00
James Molloy
0dc4708fca [ARM] Promote small global constants to constant pools
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:

      ldr r0, .CPI0
      bl printf
      bx lr
    .CPI0: &format_string
    format_string: .asciz "hello, world!\n"

We can emit:

      adr r0, .CPI0
      bl printf
      bx lr
    .CPI0: .asciz "hello, world!\n"

This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).

This recommit contains fixes for a nasty bug related to fast-isel fallback - because
fast-isel doesn't know about this optimization, if it runs and emits references to
a string that we inline (because fast-isel fell back to SDAG) we will end up
with an inlined string and also an out-of-line string, and we won't emit the
out-of-line string, causing backend failures.

It also contains fixes for emitting .text relocations which made the sanitizer
bots unhappy.

llvm-svn: 281715
2016-09-16 10:17:04 +00:00
Evgeniy Stepanov
a0601a40f7 Revert "[ARM] Promote small global constants to constant pools"
This reverts r281604, which adds text relocations to ARM binaries.

llvm-svn: 281645
2016-09-15 19:13:32 +00:00
James Molloy
fe7fd879d7 [ARM] Promote small global constants to constant pools
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:

      ldr r0, .CPI0
      bl printf
      bx lr
    .CPI0: &format_string
    format_string: .asciz "hello, world!\n"

We can emit:

      adr r0, .CPI0
      bl printf
      bx lr
    .CPI0: .asciz "hello, world!\n"

This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).

This recommit contains fixes for a nasty bug related to fast-isel fallback - because
fast-isel doesn't know about this optimization, if it runs and emits references to
a string that we inline (because fast-isel fell back to SDAG) we will end up
with an inlined string and also an out-of-line string, and we won't emit the
out-of-line string, causing backend failures.

llvm-svn: 281604
2016-09-15 12:30:27 +00:00
Evgeniy Stepanov
e97d3b90b9 Revert "[ARM] Promote small global constants to constant pools"
Breaks Android tests by introducing text relocations to ARM binaries.

http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/25362/steps/run%20asan%20lit%20tests%20%5Barm%2Fbullhead-userdebug%2FMTC20F%5D/logs/stdio

llvm-svn: 281526
2016-09-14 20:02:30 +00:00
James Molloy
13065b00ba [ARM] Promote small global constants to constant pools
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:

      ldr r0, .CPI0
      bl printf
      bx lr
    .CPI0: &format_string
    format_string: .asciz "hello, world!\n"

We can emit:

      adr r0, .CPI0
      bl printf
      bx lr
    .CPI0: .asciz "hello, world!\n"

This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).

llvm-svn: 281484
2016-09-14 14:47:27 +00:00
James Molloy
9790d8f81d Revert "[Thumb] Teach ISel how to lower compares of AND bitmasks efficiently"
This reverts commit r281323. It caused chromium test failures and a selfhost failure.

llvm-svn: 281451
2016-09-14 09:45:28 +00:00
James Molloy
043d613791 Revert "[ARM] Promote small global constants to constant pools"
This reverts commit r281314. Speculatively revert as it's possible this caused linker errors: http://lab.llvm.org:8011/builders/clang-native-arm-lnt/builds/19656

llvm-svn: 281327
2016-09-13 12:45:51 +00:00
Pablo Barrio
bb6984d401 [ARM] Add ".code 32" to functions in the ARM instruction set
Before, only Thumb functions were marked as ".code 16". These
".code x" directives are effective until the next directive of its
kind is encountered. Therefore, in code with interleaved ARM and
Thumb functions, it was possible to declare a function as ARM and
end up with a Thumb function after assembly. A test has been added.

An existing test has also been fixed to take this change into
account.

Reviewers: aschwaighofer, t.p.northover, jmolloy, rengolin

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: https://reviews.llvm.org/D24337

llvm-svn: 281324
2016-09-13 12:18:15 +00:00
James Molloy
d246c598de [Thumb] Teach ISel how to lower compares of AND bitmasks efficiently
For the common pattern (CMPZ (AND x, #bitmask), #0), we can do some more efficient instruction selection if the bitmask is one consecutive sequence of set bits (32 - clz(bm) - ctz(bm) == popcount(bm)).

1) If the bitmask touches the LSB, then we can remove all the upper bits and set the flags by doing one LSLS.
2) If the bitmask touches the MSB, then we can remove all the lower bits and set the flags with one LSRS.
3) If the bitmask has popcount == 1 (only one set bit), we can shift that bit into the sign bit with one LSLS and change the condition query from NE/EQ to MI/PL (we could also implement this by shifting into the carry bit and branching on BCC/BCS).
4) Otherwise, we can emit a sequence of LSLS+LSRS to remove the upper and lower zero bits of the mask.

1-3 require only one 16-bit instruction and can elide the CMP. 4 requires two 16-bit instructions but can elide the CMP and doesn't require materializing a complex immediate, so is also a win.

llvm-svn: 281323
2016-09-13 12:12:32 +00:00
James Molloy
3e4bc66134 [ARM] Promote small global constants to constant pools
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:

      ldr r0, .CPI0
      bl printf
      bx lr
    .CPI0: &format_string
    format_string: .asciz "hello, world!\n"

We can emit:

      adr r0, .CPI0
      bl printf
      bx lr
    .CPI0: .asciz "hello, world!\n"

This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).

llvm-svn: 281314
2016-09-13 10:28:11 +00:00
Peter Collingbourne
d4135bbc30 DebugInfo: New metadata representation for global variables.
This patch reverses the edge from DIGlobalVariable to GlobalVariable.
This will allow us to more easily preserve debug info metadata when
manipulating global variables.

Fixes PR30362. A program for upgrading test cases is attached to that
bug.

Differential Revision: http://reviews.llvm.org/D20147

llvm-svn: 281284
2016-09-13 01:12:59 +00:00
Nico Weber
7c31d0ebc0 Revert r281215, it caused PR30358.
llvm-svn: 281263
2016-09-12 21:40:50 +00:00
James Molloy
3d06ff22b7 Revert "[ARM] Promote small global constants to constant pools"
This reverts commit r281213. It made a bot go bang: http://lab.llvm.org:8011/builders/clang-cmake-armv7-a15-full/builds/14625

llvm-svn: 281228
2016-09-12 16:18:23 +00:00
James Molloy
1e1b56bd48 [Thumb] Teach ISel how to lower compares of AND bitmasks efficiently
For the common pattern (CMPZ (AND x, #bitmask), #0), we can do some more efficient instruction selection if the bitmask is one consecutive sequence of set bits (32 - clz(bm) - ctz(bm) == popcount(bm)).

1) If the bitmask touches the LSB, then we can remove all the upper bits and set the flags by doing one LSLS.
2) If the bitmask touches the MSB, then we can remove all the lower bits and set the flags with one LSRS.
3) If the bitmask has popcount == 1 (only one set bit), we can shift that bit into the sign bit with one LSLS and change the condition query from NE/EQ to MI/PL (we could also implement this by shifting into the carry bit and branching on BCC/BCS).
4) Otherwise, we can emit a sequence of LSLS+LSRS to remove the upper and lower zero bits of the mask.

1-3 require only one 16-bit instruction and can elide the CMP. 4 requires two 16-bit instructions but can elide the CMP and doesn't require materializing a complex immediate, so is also a win.

llvm-svn: 281215
2016-09-12 14:30:48 +00:00