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2013-09-05PNaCl bitcode: Indirect calls: Store return type instead of function typeMark Seaborn
For indirect call instructions (INST_CALL_INDIRECT), it's not necessary to store the full function type. The argument types are already known from the arguments in the instruction. We only need to store the return type to be able to reconstruct the full function type. Storing only the return type ID will make the bitcode a little more compact. Return type IDs will be frequently-used scalar types, which can be given smaller type IDs than function types, which are less frequently used. This potentially makes the writer simpler: In principle, the writer no longer needs to make a pass across all functions' bodies to determine which function types are used in order to build the type table. BUG=https://code.google.com/p/nativeclient/issues/detail?id=3544 TEST=*.ll tests Review URL: https://codereview.chromium.org/23521005
2013-09-05PNaCl bitcode: Don't output the LABEL type in the type tableMark Seaborn
The type ID for the "label" type is never referenced. The "label" type was only being added to the type table because EnumerateType() treats BasicBlock and Value operands the same. However, the rest of the reader and writer treat BasicBlock operands specially and not like other Values. Change some tests to use wildcards for some type IDs. This is so that I don't have to update all the type ID numbers now that the generated type tables have changed. BUG=https://code.google.com/p/nativeclient/issues/detail?id=3590 TEST=run small_tests with v2 bitcode format enabled Review URL: https://codereview.chromium.org/23530031
2013-09-04Remove ARRAY/VECTOR types from PNaCl bitcode files.Karl Schimpf
The value selector list for switch statements are represented using ARRAY/VECTOR constants, but this information is not put into the bitcode file. This CL changes the value enumerator to not emit these constants. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3649 R=mseaborn@chromium.org Review URL: https://codereview.chromium.org/23653013
2013-09-04PNaCl bitcode reader: Disallow pointer-typed arguments in indirect callsMark Seaborn
Make the bitcode reader stricter, so that it disallows pointer arguments in indirect function calls, which are disallowed by the PNaCl ABI checker. Pointer arguments in function calls are only allowed in intrinsic calls, and calls to intrinsics must always be direct calls, not indirect calls. This involves removing two tests that specifically test for pointer args. This is in preparation for tweaking how indirect calls are represented, so that they store the call's return type rather than the function type. BUG=https://code.google.com/p/nativeclient/issues/detail?id=3544 TEST=*.ll tests Review URL: https://codereview.chromium.org/23660005
2013-09-03Remove generating STRUCT_ANON records in PNaCl bitcode files.Karl Schimpf
Don't generate types for elided cast instructions, since they are never put into the bitcode file. In addition, do not generate a type id for the types of global variables, because they are never needed. Don't allow STRUCT_ANON in bitcode files PNaClVersion==2. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3648 R=jvoung@chromium.org Review URL: https://codereview.chromium.org/23455023
2013-09-03Remove all remaining pointer casts from PNaCl bitcode files.Karl Schimpf
For PNaClVersion==2, removes remaining pointer casts from bitcode files. This includes: * Return value can be casted to a scalar value. * Intrinsic calls may return an inherent pointer, which may need casting to a scalar value. Also modifies tests bitcast-elide.ll and inttoptr-elide.ll by removing tests that assumed there were remaining pointer bitcasts that do not get removed. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3544 R=jvoung@chromium.org Review URL: https://codereview.chromium.org/23524003
2013-08-30Revert some ARM byval localmods since byval+varargs are not in stable pexes.Jan Voung
Localmods came from: https://codereview.chromium.org/10825082/, and earlier. (1) The original change was so that byval parameters always go on the stack. That part was added because the original ARM code was buggy, and did not actually make a copy of the value, modifying the caller's struct (ouch!). (2) Then came a localmod to make all arguments following a byval go on the stack and to make the var-args code aware of that. This is so that arguments stay in the correct order for var-args to pick up. For (1) there has been some work upstream to make it work better. In any case, clang with --target=armv7a-...-gnueabi only used byval in some limited cases -- when the size of the struct is > 64 bytes where the backend will know that part of it could be in regs, and the rest can be memcpy'ed to the stack. For le32, clang will still generate byval without satisfying the same ARM condition (only for structs bigger than 64 bytes), so it could be *very bad* if we didn't have the ABI simpification passes rewrite the byval and try to let the ARM backend do things with byval... TEST=the GCC torture tests: va-arg-4.c, and 20030914-2.c and the example in issue 2746 still pass. BUG=none, cleanup R=dschuff@chromium.org Review URL: https://codereview.chromium.org/23691009
2013-08-30Revert "Remove generating STRUCT_ANON records in PNaCl bitcode files."Karl Schimpf
This reverts commit 2302e5d39e2302962d1a0e45d60e00ed47b9b061. BUG= R=eliben@chromium.org Review URL: https://codereview.chromium.org/23827002
2013-08-30Remove generating STRUCT_ANON records in PNaCl bitcode files.Karl Schimpf
Don't generate types for elided cast instructions, since they are never put into the bitcode file. In addition, do not generate a type id for the types of global variables, because they are never needed. Don't allow and STRUCT records in bitcode files when PNaClVersion==2. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3648 R=mseaborn@chromium.org Review URL: https://codereview.chromium.org/23431008
2013-08-29PNaCl bitcode: Remove handling of named struct typesMark Seaborn
Named struct types should not appear in LLVM IR that passes the PNaCl ABI verifier. Remove the test struct-types.ll because it no longer passes. Handling of TYPE_CODE_STRUCT_ANON must remain for now until this issue is fixed: https://code.google.com/p/nativeclient/issues/detail?id=3648 BUG=https://code.google.com/p/nativeclient/issues/detail?id=3590 TEST=PNaCl toolchain trybots Review URL: https://codereview.chromium.org/23490018
2013-08-28Handle pointer conversions for call instructions.Karl Schimpf
This also should complete the changes associated with removing pointer cast instructions from the PNaCl bitcode file. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3544 R=dschuff@chromium.org, jvoung@chromium.org Review URL: https://codereview.chromium.org/23482002
2013-08-26Elide pointer to int casts on phi nodes.Karl Schimpf
Handles the eliding of pointer to integer casts operands of the phi node. Also caches unelided casts generated in the reader (removing duplicates within the same block). This reduces the size of thawed pnacl-llc.pexe by about 2%. BUG= https://code.google.com/p/nativeclient/issues/detailid=3544 R=mseaborn@chromium.org Review URL: https://codereview.chromium.org/22909016
2013-08-14Remove ptrtoint instructions from the PNaCl bitcode file.Karl Schimpf
Removes ptrtoint instructions when applicable (currently only in stores), and add them back just before their use. Note: This code does not handle ptrtoint casts for calls and phi nodes, binary operators, etc. because handling of casts for these instructions has not been added yet. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3544 R=jvoung@chromium.org Review URL: https://codereview.chromium.org/22633002
2013-08-14Allow record-level printing by pnacl-bcanalyzer.Karl Schimpf
BUG= https://code.google.com/p/nativeclient/issues/detail?id=3627 R=jvoung@chromium.org Review URL: https://codereview.chromium.org/23060004
2013-08-09Properly support 16-bit atomics on x86-32.JF Bastien
16-bit atomics aren't handled properly by the current validator, this patch changes the translator so that on x86-32 it emulates 16-bit atomics with 32-bit atomics in a compare-exchange loop. TEST= ./scons run_synchronization_sync_test bitcode=1 platform=x86-32 BUG= https://code.google.com/p/nativeclient/issues/detail?id=3579 BUG= https://code.google.com/p/nativeclient/issues/detail?id=2981 BUG= https://code.google.com/p/nativeclient/issues/detail?id=3475 R=dschuff@chromium.org Review URL: https://codereview.chromium.org/22760002
2013-08-07Add the new @llvm.nacl.atomic.fence.all intrinsicJF Bastien
This is a follow-up to: https://codereview.chromium.org/22240002/ And requires the Clang changes from: https://codereview.chromium.org/22294002/ This new intrinsic represents ``asm("":::"~{memory}")`` as well as ``__sync_synchronize()``, and in IR it corresponds to a sequentially-consistent fence surrounded by ``call void asm sideeffect "", "~{memory}"()``. R=jvoung@chromium.org TEST= ninja check-all BUG= https://code.google.com/p/nativeclient/issues/detail?id=3475 Review URL: https://codereview.chromium.org/22474008
2013-08-05Fix handling of the volatile bit of loads/stores in PNaCl bitcode files.Karl Schimpf
Fixes so that the volatile bit is no longer put into the bitcode file, since the volatile bit is not in the PNaCl ABI. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3610 R=jvoung@chromium.org Review URL: https://codereview.chromium.org/21949006
2013-08-02Remove unnecessary pointer casts on store instructions.Karl Schimpf
BUG= https://code.google.com/p/nativeclient/issues/detail?id=3544 R=mseaborn@chromium.org Review URL: https://codereview.chromium.org/21964002
2013-08-02Remove duplicate 'we' in comment.Karl Schimpf
Fixes change in CL https://codereview.chromium.org/21614002 that was overlooked. BUG=None R=jvoung@chromium.org Review URL: https://codereview.chromium.org/21908004
2013-08-02Remove the bitcast (of global values) from load instructions.Karl Schimpf
Adds the eliding of bitcasts that are used as an argument to instructions that expect normalized pointers. Currently, the checked in code only checks normalized pointers for load instructions. Hence, the restriction to load instructions. As more instructions are modified to check for normalized pointers, this code will apply to those instructions. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3544 R=mseaborn@chromium.org Review URL: https://codereview.chromium.org/21614002
2013-08-01Add Intrinsic::nacl_atomic_is_lock_freeJF Bastien
This is part of a bigger CL to fix C++11 in PNaCl, to commit in the following order: - https://codereview.chromium.org/20552002 - https://codereview.chromium.org/20554002 - https://codereview.chromium.org/20560002 - https://codereview.chromium.org/20561002 This should be the last PNaCl ABI change for C11/C+11 atomic support. Note that Clang already has a builtin for lock-free, but it's partly resolved by Clang's ExprConstant.cpp and CGBuiltin.cpp, whereas what we want is a call that becomes a constant at translation-time. I made the translation part fairly general so it's easy to support architectures where ``true`` isn't always the right answer. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3475 TEST= ./scons run_synchronization_cpp11_test --verbose bitcode=1 platform=x86-64 TEST= ninja check-all R=dschuff@chromium.org Review URL: https://codereview.chromium.org/20554002
2013-08-01Remove the inttoptr dependency from load instructions.Karl Schimpf
Elides inttoptr casts used (exclusively) in load instructions when PNaClVersion=2. This is an incremental start on removing the inttoptr instruction from the PNaCl wire format (See issue 3544 for more information on the strategy of removing ptrtoint). Also modifies PNaCl bitcode reader/writer to accept PNaClVersion=1 as supported, and PNaClVersion=2 as unsupported but readable (allowing pnacl-freeze and pnacl-thaw to work on such files). Also allows command-line option --pnacl-version for setting PNaClVersion in the PNaCl bitcode writer. Also fixes some problems on PNaCl bitcode headers, using common support to determine when the read/written PNaCl bitcode file is valid. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3544 R=jvoung@chromium.org Review URL: https://codereview.chromium.org/5812155903377408
2013-07-30Rewrite ``asm("":::"memory")`` to ``fence seq_cst``JF Bastien
This is often used as a compiler barrier and should "just work" in user code. BUG= https://code.google.com/p/nativeclient/issues/detail?id=2345 R=eliben@chromium.org TEST= (cd ./pnacl/build/llvm_x86_64 && ninja check-all) Review URL: https://codereview.chromium.org/21178002
2013-07-25Clean some PNaCl-specific tests.Jim Stichnoth
BUG= https://code.google.com/p/nativeclient/issues/detail?id=3588 R=jvoung@chromium.org Review URL: https://codereview.chromium.org/19606003
2013-07-24Hide the x86-64 sandbox base address.Jim Stichnoth
Prevent sandbox addresses from being written to the stack. This covers the following cases: 1. Function calls manually push a masked return address and jump to the target, rather than using the call instruction. 2. When the function prolog chooses to use a frame pointer (rbp), it saves a masked version of the old rbp. 3. Indirect branches (jumps, calls, and returns) uniformly use r11 to construct the 64-bit target address. 4. Register r11 is marked as reserved (similar to r15) so that the register allocator won't inadvertently spill a code address to the stack. These transformations can be disabled for performance testing with the flag "-sfi-hide-sandbox-base=false". BUG= https://code.google.com/p/nativeclient/issues/detail?id=1235 R=eliben@chromium.org, mseaborn@chromium.org Review URL: https://codereview.chromium.org/19505003
2013-07-23Cherrypick test from r186226 - Fix ARM paired GPR COPY loweringJF Bastien
BUG= test the fix that was already cherrypicked TEST= self R=eliben@chromium.org Review URL: https://codereview.chromium.org/19704008
2013-07-22Cherrypick upstream ARM FastISel ext patchesJF Bastien
Specifically: r186489 - Fix ARMFastISel::ARMEmitIntExt shift emission r183794 - ARM FastISel fix sext/zext fold r183601 - Fix unused variable warning from my previous patch r183551 - ARM FastISel integer sext/zext improvements These should fix some failures that I had run into back then, as well as make ARM FastISel faster because it doesn't go to SelectionDAG. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3501 R=jvoung@chromium.org TEST= make check-all Review URL: https://codereview.chromium.org/19992002
2013-07-22Disallow dev/private intrinsics by default (only llvm.nacl.target.arch remains)Jan Voung
BUG=https://code.google.com/p/nativeclient/issues/detail?id=3525 R=jfb@chromium.org Review URL: https://codereview.chromium.org/19668004
2013-07-20Remove prefetchJF Bastien
Following our discussion in the related bug, prefetch will not be part of our initial stable ABI. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3531 TEST= cd ./pnacl/build/llvm_x86_64; ninja check R=jvoung@chromium.org Review URL: https://codereview.chromium.org/19771015
2013-07-19Simplify the test by removing unnecessary function body.Eli Bendersky
Suggested in review: https://codereview.chromium.org/19705002/ BUG=None R=jvoung@chromium.org Review URL: https://codereview.chromium.org/19774012
2013-07-18Merge remote-tracking branch 'origin/master'Eli Bendersky
2013-07-18Port new tests from origin/masterEli Bendersky
2013-07-18Increase coverage of NaCl-specific LLVM regression tests.Eli Bendersky
The issues these tests exercise came up in the recent merge of LLVM 3.3; Since it's considerably more difficult to debug problems in scons tests or sbtc tests, it makes sense to increase the coverate of LLVM regression tests as much as possible. These tests help resolve merging issues relatively quickly and should provide a first-line defense against problem arising in the NaCl specific LOCALMODs we have within LLVM. BUG=https://code.google.com/p/nativeclient/issues/detail?id=3578 R=jfb@chromium.org Review URL: https://codereview.chromium.org/19705002
2013-07-17Disallow a global address in the x86-64 displacement field.Jim Stichnoth
This applies only to %r15 sandboxed memory references. The problem is that if the index register is negative, the sandboxing operation will cause the index to become a large positive 32-bit value, which combined with the displacement, will overflow and try to reference memory outside the sandbox. This situation may legitimately occur if the compiler happens to construct a (constant) interior pointer to the middle of the global struct/array, and then dereferences it with a variable offset. After this fix, pnacl/scripts/testsuite_known_failures_pnacl.txt can be updated to remove the "aha x86-64" known failure. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3517 R=eliben@chromium.org Review URL: https://codereview.chromium.org/17987002
2013-07-16Fixing make check errors...Eli Bendersky
2013-07-15Merge commit '7dfcb84fc16b3bf6b2379713b53090757f0a45f9'Eli Bendersky
Conflicts: docs/LangRef.rst include/llvm/CodeGen/CallingConvLower.h include/llvm/IRReader/IRReader.h include/llvm/Target/TargetMachine.h lib/CodeGen/CallingConvLower.cpp lib/IRReader/IRReader.cpp lib/IRReader/LLVMBuild.txt lib/IRReader/Makefile lib/LLVMBuild.txt lib/Makefile lib/Support/MemoryBuffer.cpp lib/Support/Unix/PathV2.inc lib/Target/ARM/ARMBaseInstrInfo.cpp lib/Target/ARM/ARMISelLowering.cpp lib/Target/ARM/ARMInstrInfo.td lib/Target/ARM/ARMSubtarget.cpp lib/Target/ARM/ARMTargetMachine.cpp lib/Target/Mips/CMakeLists.txt lib/Target/Mips/MipsDelaySlotFiller.cpp lib/Target/Mips/MipsISelLowering.cpp lib/Target/Mips/MipsInstrInfo.td lib/Target/Mips/MipsSubtarget.cpp lib/Target/Mips/MipsSubtarget.h lib/Target/X86/X86FastISel.cpp lib/Target/X86/X86ISelDAGToDAG.cpp lib/Target/X86/X86ISelLowering.cpp lib/Target/X86/X86InstrControl.td lib/Target/X86/X86InstrFormats.td lib/Transforms/IPO/ExtractGV.cpp lib/Transforms/InstCombine/InstCombineCompares.cpp lib/Transforms/Utils/SimplifyLibCalls.cpp test/CodeGen/X86/fast-isel-divrem.ll test/MC/ARM/data-in-code.ll tools/Makefile tools/llvm-extract/llvm-extract.cpp tools/llvm-link/CMakeLists.txt tools/opt/CMakeLists.txt tools/opt/LLVMBuild.txt tools/opt/Makefile tools/opt/opt.cpp
2013-07-15Run the LLVM IR verifier just once in pnacl-llc.Eli Bendersky
By default, using the path inherited from llc, the verifier is run twice. We only need it to run once right after reading the bitcode in and before the ABI verifier runs. BUG=https://code.google.com/p/nativeclient/issues/detail?id=3553 R=jvoung@chromium.org Review URL: https://codereview.chromium.org/18920004
2013-07-13Concurrency support for PNaCl ABIJF Bastien
Add portable support for concurrency in PNaCl's ABI: - Promote volatile to atomic. - Promote all memory ordering to sequential consistency. - Rewrite all atomic operations to frozen NaCl intrinsics for pexe. - Rewrite atomic intrinsics to LLVM instructions for translation. This change also adds documentation to the PNaCl language reference, as well as tests where it makes sense. A future CL could clean up more of our code which mentions atomics, volatiles, memory orderings. Multiple reviewers because this is a big patch: - eliben: LLVM-fu and ResolvePNaClIntrinsics. - dschuff: ABI stability. - mseaborn: ABI stability. - sehr: Tron-duty (fight for the user's programs to work). BUG= https://code.google.com/p/nativeclient/issues/detail?id=3475 R=dschuff@chromium.org, eliben@chromium.org, sehr@google.com TEST= (cd ./pnacl/build/llvm_x86_64; ninja check-all) && ./pnacl/test.sh test-x86-32 && ./pnacl/test.sh test-x86-64 && ./pnacl/test.sh test-arm && ./pnacl/test.sh test-x86-32-sbtc && ./pnacl/test.sh test-x86-64-sbtc && ./pnacl/test.sh test-arm-sbtc Review URL: https://codereview.chromium.org/17777004
2013-07-09Make GlobalOpt's GV-by-alloca replacement work for PNaCl.Eli Bendersky
GlobalOpt currently assumes only an external "main" is the "real main". This is no longer the case for PNaCl, where we internalize "main". Make the test more strict and PNaCl specific by checking that "main" is just used once - in a call from "_start", but does not have to be external. Note that this also addresses a possible bug in the optimization for C code, since C does not guarantee that main is not recursive. This CL's purpose is to address a SPEC performance regression - 10% in 183.equake. The regression appeared after our ABI change that made 'main' internal, which disabled this particular optimization. The CL addresses this by re-enabling the optimization and also being more C-standard conforming. BUG=None Review URL: https://codereview.chromium.org/18615015
2013-07-09PNaCl: Fix negative relocation addends on x86-32Mark Seaborn
Disable an assertion. This assertion made the behaviour on x86-32 inconsistent with x86-64 and ARM. BUG=https://code.google.com/p/nativeclient/issues/detail?id=3548 TEST=*.ll tests + PNaCl toolchain trybots Review URL: https://codereview.chromium.org/18261008
2013-07-08Fix for a regression caused by the LoopVectorizer whenTom Stellard
vectorizing loops with memory accesses to non-zero address spaces. It simply dropped the AS info. Fixes PR16306. Merged from r184103 Author: Pekka Jaaskelainen <pekka.jaaskelainen@tut.fi> Date: Mon Jun 17 18:49:06 2013 +0000 git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_33@185869 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-08R600: Fix R600ControlFlowFinalizer not considering VTX_READ 128 bit dst regTom Stellard
Patch by: Vincent Lejeune https://bugs.freedesktop.org/show_bug.cgi?id=64877 NOTE: This is a candidate for the 3.3 branch. Merged from r182600 Author: Tom Stellard <thomas.stellard@amd.com> Date: Thu May 23 18:26:42 2013 +0000 git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_33@185868 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-03Do not fail when library functions are declared incorrectly.Eli Bendersky
Instead, defer the undefined behavior to runtime. BUG=https://code.google.com/p/nativeclient/issues/detail?id=3537 R=mseaborn@chromium.org Review URL: https://codereview.chromium.org/18552007
2013-07-03Don't generate Type ID's for global variable fields.Karl Schimpf
Also removed local MaxGlobalType in WriteModuleInfo because it calls VE.getTypeID(GV->getTYpe(), which is no longer defined for globals. Also noted that MaxAlignment in WriteModuleInfo was no longer used and removed it. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3541 R=mseaborn@chromium.org Review URL: https://codereview.chromium.org/18185005
2013-07-03Cleanup output of pnacl-bcanalyzer.Karl Schimpf
(1) Fix spacing in header of record histogram so that columns line up. (2) Only print 8 operands per line in the dump. Keeps lines from getting too long. BUG=None R=jvoung@chromium.org, mseaborn@chromium.org Review URL: https://codereview.chromium.org/18147006
2013-07-02Move LLVM sqrt intrinsic to stable (for float and doubles).Jan Voung
On the hardware that we support, they are implemented by instructions and have consistent behavior for -0.0, values less than -0.0, infinity, and nan. We will need to be careful to guarantee the same behavior for untested hardware. TEST=run_llvm_math_intrinsics_test BUG=http://code.google.com/p/nativeclient/issues/detail?id=3378 R=jfb@chromium.org, mseaborn@chromium.org Review URL: https://codereview.chromium.org/18559005
2013-07-02Simplify globals in PNaCl wire format based on normalized constants.Karl Schimpf
Generates simple global variable records, followed by list of records defining byte initialization and relocations. BUG= https://code.google.com/p/nativeclient/issues/detail?id=3504 R=mseaborn@chromium.org Review URL: https://codereview.chromium.org/18111002
2013-07-02Enable ABI verification check for whitelisting external symbolsEli Bendersky
BUG=https://code.google.com/p/nativeclient/issues/detail?id=3339 R=mseaborn@chromium.org Review URL: https://codereview.chromium.org/18426002
2013-07-01Internalize all symbols except _start.Eli Bendersky
BUG=https://code.google.com/p/nativeclient/issues/detail?id=3532 R=mseaborn@chromium.org Review URL: https://codereview.chromium.org/18348008
2013-07-01PNaCl ABI checker: Check for exact names and types of whitelisted intrinsicsMark Seaborn
This makes the checker stricter, so that it will reject names such as "@llvm.memcpy.foo". Reuse Intrinsic::getName() and Intrinsic::getType() for checking the exact function name and type that we should expect for whitelisted intrinsics. This is simpler than writing code to check each argument type separately. intrinsics.ll test: Add some tests. Simplify existing tests by replacing multiple CHECK-NOTs with a single "CHECK-NOT: disallowed", which is stricter because it is less specific. BUG=https://code.google.com/p/nativeclient/issues/detail?id=3530 TEST=*.ll tests + PNaCl toolchain trybots Review URL: https://codereview.chromium.org/18302002