Commit Graph

3501 Commits

Author SHA1 Message Date
Oliver Stannard
92ca83cccd [ARM] Add additional matching for UBFX instructions
This adds an additional matcher to select UBFX(..) from SRL(AND(..)) in
ARMISelDAGToDAG to help with code size.

Patch by David Green.

Differential Revision: http://reviews.llvm.org/D20667

llvm-svn: 271384
2016-06-01 12:01:01 +00:00
Matthias Braun
ce0bcb78e6 ARM: Improve/fix comment in recently added test.
llvm-svn: 271340
2016-05-31 21:59:59 +00:00
Matthias Braun
fe725c9241 ARM: Do not attempt to modify register class of physregs.
Physregs have no associated register class, do not attempt to modify it
in Thumb2InstrInfo::storeRegToStackSlot()/loadFromStackSlot().

llvm-svn: 271339
2016-05-31 21:39:12 +00:00
Ahmed Bougacha
96ef87e910 [CodeGen] Promote FMINNAN/FMAXNAN like other binops.
We think it's OK to generate half fminnan because it's legal for the
transform-to type (f32; r245196). However, PromoteFloatRes was missing
the case; simply promote like the other binops, including minnum.

llvm-svn: 271317
2016-05-31 18:50:25 +00:00
Rafael Espindola
7ad97b2fe4 Add a use of shouldAssumeDSOLocal to ARM.
Now this code path knows about position independent executables.

llvm-svn: 271290
2016-05-31 15:31:55 +00:00
Ranjeet Singh
16c24f4d6e [ARM] Add backend support for load/store intrinsics.
Added support to map intrinsics
__builtin_arm_{ldc,ldcl,ldc2,ldc2l,stc,stcl,stc2,stc2l}
to their ARM instructions.

Differential Revision: http://reviews.llvm.org/D20564

llvm-svn: 271271
2016-05-31 12:39:30 +00:00
Rafael Espindola
fe796dca90 Fix default reloc model on ARM.
llvm-svn: 271111
2016-05-28 10:41:15 +00:00
Renato Golin
9be88629d5 Revert "Revert "Map DynamicNoPIC to Static on non-darwin.""
This reverts commit r271096, as reverting it broke even more buildbots!

But that also means I'll break on ARM again... :(

llvm-svn: 271099
2016-05-28 04:47:13 +00:00
Renato Golin
4f22c51b09 Revert "Map DynamicNoPIC to Static on non-darwin."
This reverts commit r271052, as it broke some ARM buildbots.

llvm-svn: 271096
2016-05-28 04:24:26 +00:00
Rafael Espindola
f9bda6805b Map DynamicNoPIC to Static on non-darwin.
DynamicNoPIC was only every used on darwin. This maps it to static on
ELF. It matches what is done on X86.

llvm-svn: 271052
2016-05-27 21:44:18 +00:00
Matthew Simpson
476c0afc01 [ARM, AArch64] Match additional patterns to ldN instructions
When matching an interleaved load to an ldN pattern, the interleaved access
pass checks that all users of the load are shuffles. If the load is used by an
instruction other than a shuffle, the pass gives up and an ldN is not
generated. This patch considers users of the load that are extractelement
instructions. It attempts to modify the extracts to use one of the available
shuffles rather than the load. After the transformation, the load is only used
by shuffles and will then be matched with an ldN pattern.

Differential Revision: http://reviews.llvm.org/D20250

llvm-svn: 270142
2016-05-19 21:39:00 +00:00
Ranjeet Singh
dbbbef5401 [ARM] Add cdp intrinsic tests.
- Renamed intrinsics.ll to intrinsics-coprocessor.ll
  as all the tests were testing coprocessor instructions,
  also made the test checks match the full instruction.

Differential Revision: http://reviews.llvm.org/D20393

llvm-svn: 270057
2016-05-19 12:59:17 +00:00
Rafael Espindola
8c34dd8257 Delete Reloc::Default.
Having an enum member named Default is quite confusing: Is it distinct
from the others?

This patch removes that member and instead uses Optional<Reloc> in
places where we have a user input that still hasn't been maped to the
default value, which is now clear has no be one of the remaining 3
options.

llvm-svn: 269988
2016-05-18 22:04:49 +00:00
Renato Golin
4b9c0d4dcf [llc] New diagnostic handler
Without a diagnostic handler installed, llc's behaviour is to exit on the first
error that it encounters. This is very different from the behaviour of clang
and other front ends, which try to gather as many errors as possible before
exiting.

This commit adds a diagnostic handler to llc, allowing it to find and report
more than one error. The old behaviour is preserved under a flag (-exit-on-error).

Some of the tests fail with the new diagnostic handler, so they have to use the
new flag in order to run under the previous behaviour. Some of these are known
bugs, others need further investigation. Ideally, we should fix the tests and
remove the flag at some point in the future.

Reapplied after fixing the LLDB build that was broken due to the new
DiagnosticSeverity in LLVMContext.h, and fixed an UB in the new change.

Patch by Diana Picus.

llvm-svn: 269655
2016-05-16 14:28:02 +00:00
Saleem Abdulrasool
8df2f49889 ARM: support export directives for Windows
It seems that cl will emit the export directives for Windows ARM targets.  The
fact that it did this had originally been missed and this functionality was
never implemented.  This makes it possible to rely solely on the source code for
indicating what the exported interfaces are and brings us more compatibility
with cl.

llvm-svn: 269574
2016-05-14 18:58:34 +00:00
Renato Golin
f4917d35c9 Revert "[llc] New diagnostic handler"
This reverts commit r269563. Even though now it passes all LLDB bots
after a local fix, there's a new buildbot it fails with tests that we
hadn't seen locally:

http://lab.llvm.org:8011/builders/clang-x86_64-linux-selfhost-modules/builds/15647

Adding those tests to the list to investigate.

llvm-svn: 269568
2016-05-14 14:37:11 +00:00
Renato Golin
c001e67baf [llc] New diagnostic handler
Without a diagnostic handler installed, llc's behaviour is to exit on the first
error that it encounters. This is very different from the behaviour of clang
and other front ends, which try to gather as many errors as possible before
exiting.

This commit adds a diagnostic handler to llc, allowing it to find and report
more than one error. The old behaviour is preserved under a flag (-exit-on-error).

Some of the tests fail with the new diagnostic handler, so they have to use the
new flag in order to run under the previous behaviour. Some of these are known
bugs, others need further investigation. Ideally, we should fix the tests and
remove the flag at some point in the future.

Reapplied after fixing the LLDB build that was broken due to the new
DiagnosticSeverity in LLVMContext.h.

Patch by Diana Picus.

llvm-svn: 269563
2016-05-14 13:15:22 +00:00
Tim Northover
f8b0a7af52 ARM: use callee-saved list in the order they're actually saved.
When setting the frame pointer, the offset from SP is calculated based on the
stack slot it gets allocated, but this slot is in turn based on the order of
the CSR list so that list should match the order we actually save the registers
in. Mostly it did, but in the edge-case of MachO AAPCS targets it was wrong.

llvm-svn: 269459
2016-05-13 19:16:14 +00:00
Renato Golin
1d1b82cbeb Revert "[ARM,AArch64] NFC. Add extra test cases for bswap lowering."
This reverts commit r269425, as it fails on Windows (Thumb only).

llvm-svn: 269451
2016-05-13 18:19:42 +00:00
Renato Golin
e9fa3585c5 Revert "[llc] New diagnostic handler"
This reverts commit r269428, as it breaks the LLDB build. We need to
understand how to change LLDB in the same way as LLC before landing this
again.

llvm-svn: 269432
2016-05-13 16:02:44 +00:00
Renato Golin
d7a64a5b23 [llc] New diagnostic handler
Without a diagnostic handler installed, llc's behaviour is to exit on the first
error that it encounters. This is very different from the behaviour of clang
and other front ends, which try to gather as many errors as possible before
exiting.

This commit adds a diagnostic handler to llc, allowing it to find and report
more than one error. The old behaviour is preserved under a flag (-exit-on-error).

Some of the tests fail with the new diagnostic handler, so they have to use the
new flag in order to run under the previous behaviour. Some of these are known
bugs, others need further investigation. Ideally, we should fix the tests and
remove the flag at some point in the future.

Patch by Diana Picus.

llvm-svn: 269428
2016-05-13 15:37:46 +00:00
Renato Golin
8793c521bc [ARM,AArch64] NFC. Add extra test cases for bswap lowering.
These tests were sitting in Phab for many months. They're good tests and should be in.

Patch by Charlie Turner.

llvm-svn: 269425
2016-05-13 15:10:24 +00:00
Renato Golin
d5491ab1f9 [ARM] Fixup tests to take into account mov translation. NFC.
Alter instances in the test-suite that use immediates that can be represented
in the immediate field of a MOV. The reason for doing this is that when the
LDR rt,=imm transformation to MOV rt, imm the existing tests do not need to
be modified.

Required by the patch that fixes PR25722.

Patch by Peter Smith.

llvm-svn: 269353
2016-05-12 21:22:37 +00:00
Tim Northover
b5ece527a1 ARM: stop emitting blx instructions for most calls on MachO.
I'm really not sure why we were in the first place, it's the linker's job to
convert between BL/BLX as necessary. Even worse, using BLX left Thumb calls
that could be locally resolved completely unencodable since all offsets to BLX
are multiples of 4.

rdar://26182344

llvm-svn: 269101
2016-05-10 19:17:47 +00:00
Weiming Zhao
5b5501e817 [ARM] Fix Scavenger assert due to underestimated stack size
(re-apply r268810 as it exposed an uninitialized variable in ARM MFI.
 Patch 268868 should fix that.)

Summary:
Currently, when checking if a stack is "BigStack" or not, it doesn't count into spills and arguments. Therefore, LLVM won't reserve spill slot for this actually "BigStack". This may cause scavenger failure.

Reviewers: rengolin

Subscribers: vitalybuka, aemerson, rengolin, tberghammer, danalbert, srhines, llvm-commits

Differential Revision: http://reviews.llvm.org/D19896

llvm-svn: 268869
2016-05-08 05:11:54 +00:00
Vitaly Buka
e81d96be6f Revert r268810 becase it brakes msan bot.
16802==WARNING: MemorySanitizer: use-of-uninitialized-value
    lib/Target/ARM/ARMFrameLowering.cpp:1632

llvm-svn: 268833
2016-05-07 01:54:00 +00:00
Weiming Zhao
74f12d31c1 [ARM] Fix Scavenger assert due to underestimated stack size
(this is resubmit of r268529 with minor refactoring. r268529 was reverted
 at r268536 due a memory sanitizer failure.  I have not been able to
 reproduce that failure and I checked all the variable used in my change
 but I could not spot an issue. I did some refactoring and see if it will
 give a clearer hint)

Summary:
Currently, when checking if a stack is "BigStack" or not, it doesn't count into spills and arguments. Therefore, LLVM won't reserve spill slot for this actually "BigStack". This may cause scavenger failure.

Reviewers: rengolin

Subscribers: vitalybuka, aemerson, rengolin, tberghammer, danalbert, srhines, llvm-commits

Differential Revision: http://reviews.llvm.org/D19896

llvm-svn: 268810
2016-05-06 22:20:13 +00:00
Ahmed Bougacha
16547c4e31 [CodeGen] Round [SU]INT_TO_FP result when promoting from f16.
If we don't, values that aren't precisely representable in f16 could
be used as-is in a promoted f32 operation, which would produce
incorrect results.

AArch64 had the correct behavior; add a focused test.

Fixes http://llvm.org/PR26871

llvm-svn: 268700
2016-05-06 00:58:00 +00:00
Tim Northover
df43264cf7 ARM: don't attempt to merge litpools referencing different PC-anchors.
Given something like:

    ldr r0, .LCPI0_0 (== pc-rel var)
    add r0, pc

    ldr r1, .LCPI0_1 (== pc-rel var)
    add r1, pc

we cannot combine the 2 ldr instructions and litpools because they get added to
a different pc to form the correct address. I think the original logic came
from a time when we fused the LDRpci/PICADD instructions into one
pseudo-instruction so the PC was always immediately at-hand. That's no longer
the case.

Should fix general-dynamic TLS access on Linux, and quite possibly other -fPIC
code that relies on litpools (e.g. v6m and -Oz compilations) though trivial
tweaks of the .ll test didn't provoke anything.

llvm-svn: 268662
2016-05-05 18:38:53 +00:00
Vitaly Buka
6b5c89262a Revert r268529 because it caused use-of-uninitialized-value
Summary: This reverts commit d88cc0862bf7da64850b89e9bb5ea9f95e7f1184.

#0 0xfed467 in llvm::ARMFrameLowering::determineCalleeSaves(llvm::MachineFunction&, llvm::BitVector&, llvm::RegScavenger*) const /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/Target/ARM/ARMFrameLowering.cpp:1625:52
#1 0x330d4cc in (anonymous namespace)::PEI::runOnMachineFunction(llvm::MachineFunction&) /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/CodeGen/PrologEpilogInserter.cpp:186:3
#2 0x3193e12 in llvm::MachineFunctionPass::runOnFunction(llvm::Function&) /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/CodeGen/MachineFunctionPass.cpp:60:13
#3 0x396237d in llvm::FPPassManager::runOnFunction(llvm::Function&) /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/IR/LegacyPassManager.cpp:1526:23
#4 0x3962a23 in llvm::FPPassManager::runOnModule(llvm::Module&) /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/IR/LegacyPassManager.cpp:1547:16
#5 0x3963d52 in runOnModule /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/IR/LegacyPassManager.cpp:1603:23
#6 0x3963d52 in llvm::legacy::PassManagerImpl::run(llvm::Module&) /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/IR/LegacyPassManager.cpp:1706
#7 0x6bb910 in compileModule(char**, llvm::LLVMContext&) /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/tools/llc/llc.cpp:412:5
#8 0x6b3c25 in main /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/tools/llc/llc.cpp:218:22
#9 0x7fd4a7d37ec4 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21ec4)
#10 0x625c93 in _start (/mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm_build_msan/bin/llc+0x625c93)

Reviewers:

Subscribers:

llvm-svn: 268536
2016-05-04 19:44:11 +00:00
Weiming Zhao
2373f769ce [ARM] Fix Scavenger assert due to underestimated stack size
Summary:
Currently, when checking if a stack is "BigStack" or not, it doesn't count into spills and arguments. Therefore, LLVM won't reserve spill slot for this actually "BigStack". This may cause scavenger failure.

Reviewers: rengolin

Subscribers: aemerson, rengolin, tberghammer, danalbert, srhines, llvm-commits

Differential Revision: http://reviews.llvm.org/D19896

llvm-svn: 268529
2016-05-04 18:19:33 +00:00
Ahmed Bougacha
b4af107239 [ARM] Set correct successors in CMPXCHG pseudo expansion.
transferSuccessors() would LoadCmpBB a successor of DoneBB, whereas
it should be a successor of the original MBB.

The testcase changes are caused by Thumb2SizeReduction, which
was previously confused by the broken CFG.

Follow-up to r266679.

Unfortunately, it's tricky to catch this in the verifier.

llvm-svn: 267778
2016-04-27 20:32:54 +00:00
Craig Topper
d8d6be4f99 [ARM] Expand vector ctlz_zero_undef so it becomes ctlz.
The default is Legal, which results in 'Cannot select' errors.

llvm-svn: 267521
2016-04-26 05:04:37 +00:00
Craig Topper
edb4a6ba98 [ARM] Expand v1i64 and v2i64 ctlz.
The default is legal, which results in 'Cannot select' errors.

llvm-svn: 267520
2016-04-26 05:04:33 +00:00
Richard Trieu
d7f31a31d1 Pass the test file in through stdin instead of by filename.
When passed in via filename, this test will fail if the path to the test
has the strings "f1" and "f2" in somewhere.  Pass the file through stdin
to prevent test failures due to coincidences in path names.

llvm-svn: 267517
2016-04-26 03:43:49 +00:00
Tim Northover
5c3140f745 ARM: put extern __thread stubs in a special section.
The linker needs to know that the symbols are thread-local to do its job
properly.

llvm-svn: 267473
2016-04-25 21:12:04 +00:00
Silviu Baranga
82d04260b7 [ARM] Add support for the X asm constraint
Summary:
This patch adds support for the X asm constraint.

To do this, we lower the constraint to either a "w" or "r" constraint
depending on the operand type (both constraints are supported on ARM).

Fixes PR26493

Reviewers: t.p.northover, echristo, rengolin

Subscribers: joker.eph, jgreenhalgh, aemerson, rengolin, llvm-commits

Differential Revision: http://reviews.llvm.org/D19061

llvm-svn: 267411
2016-04-25 14:29:18 +00:00
Saleem Abdulrasool
9611518646 ARM: fix __chkstk Frame Setup on WoA
This corrects the MI annotations for the stack adjustment following the __chkstk
invocation.  We were marking the original SP usage as a Def rather than Kill.
The (new) assigned value is the definition, the original reference is killed.

Adjust the ISelLowering to mark Kills and FrameSetup as well.

This partially resolves PR27480.

llvm-svn: 267361
2016-04-24 20:12:48 +00:00
NAKAMURA Takumi
4aec5fda93 Fix llvm/test/CodeGen/ARM/Windows/dbzchk.ll not to check mixed output, take #2.
llvm-svn: 267242
2016-04-22 22:51:48 +00:00
Peter Collingbourne
265ebd7d70 CodeGen: Use PLT relocations for relative references to unnamed_addr functions.
The relative vtable ABI (PR26723) needs PLT relocations to refer to virtual
functions defined in other DSOs. The unnamed_addr attribute means that the
function's address is not significant, so we're allowed to substitute it
with the address of a PLT entry.

Also includes a bonus feature: addends for COFF image-relative references.

Differential Revision: http://reviews.llvm.org/D17938

llvm-svn: 267211
2016-04-22 20:40:10 +00:00
Saleem Abdulrasool
8237008897 test: split test into two runs
Rather than checking both stdout and stderr simultaneously, split it into two
tests.  This apparently breaks on Windows where MSVCRT does not buffer output
correctly.  NFC.

Thanks to chapuni for bringing the issue to my attention!

llvm-svn: 267179
2016-04-22 18:06:51 +00:00
Saleem Abdulrasool
12b87facf4 ARM: fix test for Windows division
This was meant to be part of SVN r267080.  cbz cannot use a high register, which
would be silently truncated.  This has now been fixed.

llvm-svn: 267092
2016-04-22 01:03:38 +00:00
Saleem Abdulrasool
a028853540 ARM: restrict register class for WIN__DBZCHK
WIN__DBZCHK will insert a CBZ instruction into the stream.  This instruction
reserves 3 bits for the condition register (rn).  As such, we must ensure that
we restrict the register to a low register.  Use the tGPR class instead of GPR
to ensure that this is properly constrained.  In debug builds, we would attempt
to use lr as a condition register which would silently get truncated with no
hint that the register selection was incorrect.

llvm-svn: 267080
2016-04-21 23:53:19 +00:00
Mandeep Singh Grang
029a0567fa [LLVM] Remove unwanted --check-prefix=CHECK from unit tests. NFC.
Summary: Removed unwanted --check-prefix=CHECK from numerous unit tests.

Reviewers: t.p.northover, dblaikie, uweigand, MatzeB, tstellarAMD, mcrosier

Subscribers: mcrosier, dsanders

Differential Revision: http://reviews.llvm.org/D19279

llvm-svn: 266834
2016-04-19 23:51:52 +00:00
Tim Northover
1ee27c74cb ARM: fix assertion failure on -O0 cmpxchg.
Because lowering of CMP_SWAP_64 occurs during type legalization, there can be
i64 types produced by more than just a BUILD_PAIR or similar. My initial tests
used just incoming function args.

llvm-svn: 266828
2016-04-19 22:25:02 +00:00
Marcin Koscielnicki
3fdc257d6a [AArch64] [ARM] Make a target-independent llvm.thread.pointer intrinsic.
Both AArch64 and ARM support llvm.<arch>.thread.pointer intrinsics that
just return the thread pointer.  I have a pending patch that does the same
for SystemZ (D19054), and there are many more targets that could benefit
from one.

This patch merges the ARM and AArch64 intrinsics into a single target
independent one that will also be used by subsequent targets.

Differential Revision: http://reviews.llvm.org/D19098

llvm-svn: 266818
2016-04-19 20:51:05 +00:00
Tim Shen
e885d5e4d3 [SSP, 2/2] Create llvm.stackguard() intrinsic and lower it to LOAD_STACK_GUARD
With this change, ideally IR pass can always generate llvm.stackguard
call to get the stack guard; but for now there are still IR form stack
guard customizations around (see getIRStackGuard()). Future SSP
customization should go through LOAD_STACK_GUARD.

There is a behavior change: stack guard values are not CSEed anymore,
since we should never reuse the value in case that it has been spilled (and
corrupted). See ssp-guard-spill.ll. This also cause the change of stack
size and codegen in X86 and AArch64 test cases.

Ideally we'd like to know if the guard created in llvm.stackprotector() gets
spilled or not. If the value is spilled, discard the value and reload
stack guard; otherwise reuse the value. This can be done by teaching
register allocator to know how to rematerialize LOAD_STACK_GUARD and
force a rematerialization (which seems hard), or check for spilling in
expandPostRAPseudo. It only makes sense when the stack guard is a global
variable, which requires more instructions to load. Anyway, this seems to go out
of the scope of the current patch.

llvm-svn: 266806
2016-04-19 19:40:37 +00:00
Tim Northover
b629c77692 ARM: use a pseudo-instruction for cmpxchg at -O0.
The fast register-allocator cannot cope with inter-block dependencies without
spilling. This is fine for ldrex/strex loops coming from atomicrmw instructions
where any value produced within a block is dead by the end, but not for
cmpxchg. So we lower a cmpxchg at -O0 via a pseudo-inst that gets expanded
after regalloc.

Fortunately this is at -O0 so we don't have to care about performance. This
simplifies the various axes of expansion considerably: we assume a strong
seq_cst operation and ensure ordering via the always-present DMB instructions
rather than v8 acquire/release instructions.

Should fix the 32-bit part of PR25526.

llvm-svn: 266679
2016-04-18 21:48:55 +00:00
Adrian Prantl
75819aedf6 [PR27284] Reverse the ownership between DICompileUnit and DISubprogram.
Currently each Function points to a DISubprogram and DISubprogram has a
scope field. For member functions the scope is a DICompositeType. DIScopes
point to the DICompileUnit to facilitate type uniquing.

Distinct DISubprograms (with isDefinition: true) are not part of the type
hierarchy and cannot be uniqued. This change removes the subprograms
list from DICompileUnit and instead adds a pointer to the owning compile
unit to distinct DISubprograms. This would make it easy for ThinLTO to
strip unneeded DISubprograms and their transitively referenced debug info.

Motivation
----------

Materializing DISubprograms is currently the most expensive operation when
doing a ThinLTO build of clang.

We want the DISubprogram to be stored in a separate Bitcode block (or the
same block as the function body) so we can avoid having to expensively
deserialize all DISubprograms together with the global metadata. If a
function has been inlined into another subprogram we need to store a
reference the block containing the inlined subprogram.

Attached to https://llvm.org/bugs/show_bug.cgi?id=27284 is a python script
that updates LLVM IR testcases to the new format.

http://reviews.llvm.org/D19034
<rdar://problem/25256815>

llvm-svn: 266446
2016-04-15 15:57:41 +00:00
David Majnemer
0f26b0aeb4 [CodeGen] Teach LLVM how to lower @llvm.{min,max}num to {MIN,MAX}NAN
The behavior of {MIN,MAX}NAN differs from that of {MIN,MAX}NUM when only
one of the inputs is NaN: -NUM will return the non-NaN argument while
-NAN would return NaN.

It is desirable to lower to @llvm.{min,max}num to -NAN if they don't
have a native instruction for -NUM.  Notably, ARMv7 NEON's vmin has the
-NAN semantics.

N.B.  Of course, it is only safe to do this if the intrinsic call is
marked nnan.

llvm-svn: 266279
2016-04-14 07:13:24 +00:00