Clang CFLAGS #3
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chapuni
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The canonical form for the extended addressing mode (e.g., "[x1, w2, uxtw #3]" is for the MCInst to have the second register be the full 64-bit GPR64 register class. The instruction printer cleans up the output for display to show the 32-bit register instead, per the specification. This simplifies 205893 now that the aliasing is handled in the printer in 206495 so that the codegen path and the disassembler path give the same MCInst form.
chapuni
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For pattern like ((x >> C1) & Mask) << C2, DAG combiner may convert it into (x >> (C1-C2)) & (Mask << C2), which makes pattern matching of ubfx more difficult. For example: Given %shr = lshr i64 %x, 4 %and = and i64 %shr, 15 %arrayidx = getelementptr inbounds [8 x [64 x i64]]* @arr, i64 0, %i64 2, i64 %and %0 = load i64* %arrayidx With current shift folding, it takes 3 instrs to compute base address: lsr x8, x0, #1 and x8, x8, #0x78 add x8, x9, x8 If using ubfx, it only needs 2 instrs: ubfx x8, x0, #4, #4 add x8, x9, x8, lsl #3 This fixes bug 19589
chapuni
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chapuni
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FastISel didn't take much advantage of the different addressing modes available to it on AArch64. This commit allows the ComputeAddress method to recognize more addressing modes that allows shifts and sign-/zero-extensions to be folded into the memory operation itself. For Example: lsl x1, x1, #3 --> ldr x0, [x0, x1, lsl #3] ldr x0, [x0, x1] sxtw x1, w1 lsl x1, x1, #3 --> ldr x0, [x0, x1, sxtw #3] ldr x0, [x0, x1]
chapuni
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…15597). Note: This was originally reverted to track down a buildbot error. Reapply without any modifications. Original commit message: FastISel didn't take much advantage of the different addressing modes available to it on AArch64. This commit allows the ComputeAddress method to recognize more addressing modes that allows shifts and sign-/zero-extensions to be folded into the memory operation itself. For Example: lsl x1, x1, #3 --> ldr x0, [x0, x1, lsl #3] ldr x0, [x0, x1] sxtw x1, w1 lsl x1, x1, #3 --> ldr x0, [x0, x1, sxtw #3] ldr x0, [x0, x1]
chapuni
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Our internal test reveals such case should not be transformed: cmp x17, #3 b.lt .LBB10_15 ... subs x12, x12, #1 b.gt .LBB10_1 where x12 is a liveout, becomes: cmp x17, #2 b.le .LBB10_15 ... subs x12, x12, #2 b.ge .LBB10_1 Unable to provide test case as it's difficult to reproduce on community branch. http://reviews.llvm.org/D6048 Patch by Zhaoshi Zheng <[email protected]>!
chapuni
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This commit introduces heap-use-after-free detected by ASan. Here is the output
for one of several tests that detect it:
******************** TEST 'LLVM :: Linker/AppendingLinkage.ll' FAILED ********************
Command Output (stderr):
--
=================================================================
==2122==ERROR: AddressSanitizer: heap-use-after-free on address 0x60c00000b9c8 at pc 0x0000005d05d1 bp 0x7fff64ed27c0 sp 0x7fff64ed27b8
READ of size 4 at 0x60c00000b9c8 thread T0
#0 0x5d05d0 in llvm::GlobalValue::setUnnamedAddr(bool) /usr/local/google/home/chandlerc/src/llvm/build/../include/llvm/IR/GlobalValue.h:115:35
#1 0x69fff1 in (anonymous namespace)::ModuleLinker::linkGlobalValueProto(llvm::GlobalValue*) /usr/local/google/home/chandlerc/src/llvm/build/../lib/Linker/LinkModules.cpp:1041:5
#2 0x697229 in (anonymous namespace)::ModuleLinker::run() /usr/local/google/home/chandlerc/src/llvm/build/../lib/Linker/LinkModules.cpp:1485:9
#3 0x696542 in llvm::Linker::linkInModule(llvm::Module*) /usr/local/google/home/chandlerc/src/llvm/build/../lib/Linker/LinkModules.cpp:1621:10
#4 0x4a2db7 in main /usr/local/google/home/chandlerc/src/llvm/build/../tools/llvm-link/llvm-link.cpp:116:9
#5 0x7f4ae61e5ec4 in __libc_start_main /build/buildd/eglibc-2.19/csu/libc-start.c:287
#6 0x41eb71 in _start (/usr/local/google/home/chandlerc/src/llvm/build/bin/llvm-link+0x41eb71)
0x60c00000b9c8 is located 72 bytes inside of 128-byte region [0x60c00000b980,0x60c00000ba00)
freed by thread T0 here:
#0 0x4a1e6b in operator delete(void*) /usr/local/google/home/chandlerc/src/llvm/opt-build/../projects/compiler-rt/lib/asan/asan_new_delete.cc:94:3
#1 0x5d1a7a in llvm::iplist<llvm::GlobalVariable, llvm::ilist_traits<llvm::GlobalVariable> >::erase(llvm::ilist_iterator<llvm::GlobalVariable>) /usr/local/google/home/chandlerc/src/llvm/build/../inclu
de/llvm/ADT/ilist.h:466:5
#2 0x5d1980 in llvm::GlobalVariable::eraseFromParent() /usr/local/google/home/chandlerc/src/llvm/build/../lib/IR/Globals.cpp:204:3
#3 0x6a8a4d in (anonymous namespace)::ModuleLinker::linkAppendingVarProto(llvm::GlobalVariable*, llvm::GlobalVariable const*) /usr/local/google/home/chandlerc/src/llvm/build/../lib/Linker/LinkModules.
cpp:980:3
#4 0x6a7403 in (anonymous namespace)::ModuleLinker::linkGlobalVariableProto(llvm::GlobalVariable const*, llvm::GlobalValue*, bool) /usr/local/google/home/chandlerc/src/llvm/build/../lib/Linker/LinkMod
ules.cpp:1074:11
#5 0x69ff4e in (anonymous namespace)::ModuleLinker::linkGlobalValueProto(llvm::GlobalValue*) /usr/local/google/home/chandlerc/src/llvm/build/../lib/Linker/LinkModules.cpp:1028:13
#6 0x697229 in (anonymous namespace)::ModuleLinker::run() /usr/local/google/home/chandlerc/src/llvm/build/../lib/Linker/LinkModules.cpp:1485:9
#7 0x696542 in llvm::Linker::linkInModule(llvm::Module*) /usr/local/google/home/chandlerc/src/llvm/build/../lib/Linker/LinkModules.cpp:1621:10
#8 0x4a2db7 in main /usr/local/google/home/chandlerc/src/llvm/build/../tools/llvm-link/llvm-link.cpp:116:9
#9 0x7f4ae61e5ec4 in __libc_start_main /build/buildd/eglibc-2.19/csu/libc-start.c:287
previously allocated by thread T0 here:
#0 0x4a192b in operator new(unsigned long) /usr/local/google/home/chandlerc/src/llvm/opt-build/../projects/compiler-rt/lib/asan/asan_new_delete.cc:62:35
#1 0x61d85c in llvm::User::operator new(unsigned long, unsigned int) /usr/local/google/home/chandlerc/src/llvm/build/../lib/IR/User.cpp:57:19
#2 0x6a7525 in (anonymous namespace)::ModuleLinker::linkGlobalVariableProto(llvm::GlobalVariable const*, llvm::GlobalValue*, bool) /usr/local/google/home/chandlerc/src/llvm/build/../lib/Linker/LinkMod
ules.cpp:1100:3
#3 0x69ff4e in (anonymous namespace)::ModuleLinker::linkGlobalValueProto(llvm::GlobalValue*) /usr/local/google/home/chandlerc/src/llvm/build/../lib/Linker/LinkModules.cpp:1028:13
#4 0x697229 in (anonymous namespace)::ModuleLinker::run() /usr/local/google/home/chandlerc/src/llvm/build/../lib/Linker/LinkModules.cpp:1485:9
#5 0x696542 in llvm::Linker::linkInModule(llvm::Module*) /usr/local/google/home/chandlerc/src/llvm/build/../lib/Linker/LinkModules.cpp:1621:10
#6 0x4a2db7 in main /usr/local/google/home/chandlerc/src/llvm/build/../tools/llvm-link/llvm-link.cpp:116:9
#7 0x7f4ae61e5ec4 in __libc_start_main /build/buildd/eglibc-2.19/csu/libc-start.c:287
SUMMARY: AddressSanitizer: heap-use-after-free /usr/local/google/home/chandlerc/src/llvm/build/../include/llvm/IR/GlobalValue.h:115 llvm::GlobalValue::setUnnamedAddr(bool)
Shadow bytes around the buggy address:
0x0c187fff96e0: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
0x0c187fff96f0: 00 00 00 00 00 00 00 fa fa fa fa fa fa fa fa fa
0x0c187fff9700: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fa
0x0c187fff9710: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
0x0c187fff9720: 00 00 00 00 00 00 00 00 fa fa fa fa fa fa fa fa
=>0x0c187fff9730: fd fd fd fd fd fd fd fd fd[fd]fd fd fd fd fd fd
0x0c187fff9740: fa fa fa fa fa fa fa fa fd fd fd fd fd fd fd fd
0x0c187fff9750: fd fd fd fd fd fd fd fa fa fa fa fa fa fa fa fa
0x0c187fff9760: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x0c187fff9770: fa fa fa fa fa fa fa fa fd fd fd fd fd fd fd fd
0x0c187fff9780: fd fd fd fd fd fd fd fd fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Heap right redzone: fb
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack partial redzone: f4
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
ASan internal: fe
==2122==ABORTING
rnk
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May 11, 2017
…merged" This reverts r302712. The change fails with ASAN enabled: ERROR: AddressSanitizer: use-after-poison on address ... at ... READ of size 2 at ... thread T0 #0 ... in llvm::SDNode::getNumValues() const <snip>/include/llvm/CodeGen/SelectionDAGNodes.h:855:42 chapuni#1 ... in llvm::SDNode::hasAnyUseOfValue(unsigned int) const <snip>/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:7270:3 chapuni#2 ... in llvm::SDValue::use_empty() const <snip> include/llvm/CodeGen/SelectionDAGNodes.h:1042:17 chapuni#3 ... in (anonymous namespace)::DAGCombiner::MergeConsecutiveStores(llvm::StoreSDNode*) <snip>/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:12944:7 Reviewers: niravd Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D33081
rnk
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May 18, 2017
Summary: The test being added in this patch used to cause an assertion failure: /build/./bin/clang -cc1 -internal-isystem /build/lib/clang/5.0.0/include -nostdsysteminc -verify -fsyntax-only -std=c++11 -Wshadow-all /src/tools/clang/test/SemaCXX/warn-shadow.cpp -- Exit Code: 134 Command Output (stderr): -- clang: /src/tools/clang/lib/AST/ASTDiagnostic.cpp:424: void clang::FormatASTNodeDiagnosticArgument(DiagnosticsEngine::ArgumentKind, intptr_t, llvm::StringRef, llvm::StringRef, ArrayRef<DiagnosticsEngine::ArgumentValue>, SmallVectorImpl<char> &, void *, ArrayRef<intptr_t>): Assertion `isa<NamedDecl>(DC) && "Expected a NamedDecl"' failed. #0 0x0000000001c7a1b4 PrintStackTraceSignalHandler(void*) (/build/./bin/clang+0x1c7a1b4) chapuni#1 0x0000000001c7a4e6 SignalHandler(int) (/build/./bin/clang+0x1c7a4e6) chapuni#2 0x00007f30880078d0 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0xf8d0) chapuni#3 0x00007f3087054067 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x35067) #4 0x00007f3087055448 abort (/lib/x86_64-linux-gnu/libc.so.6+0x36448) #5 0x00007f308704d266 (/lib/x86_64-linux-gnu/libc.so.6+0x2e266) #6 0x00007f308704d312 (/lib/x86_64-linux-gnu/libc.so.6+0x2e312) #7 0x00000000035b7f22 clang::FormatASTNodeDiagnosticArgument(clang::DiagnosticsEngine::ArgumentKind, long, llvm::StringRef, llvm::StringRef, llvm::ArrayRef<std::pair<clang::DiagnosticsEngine::ArgumentKind, long> >, llvm::SmallVectorImpl<char>&, void*, llvm::ArrayRef<long>) (/build/ ./bin/clang+0x35b7f22) #8 0x0000000001ddbae4 clang::Diagnostic::FormatDiagnostic(char const*, char const*, llvm::SmallVectorImpl<char>&) const (/build/./bin/clang+0x1ddbae4) #9 0x0000000001ddb323 clang::Diagnostic::FormatDiagnostic(char const*, char const*, llvm::SmallVectorImpl<char>&) const (/build/./bin/clang+0x1ddb323) #10 0x00000000022878a4 clang::TextDiagnosticBuffer::HandleDiagnostic(clang::DiagnosticsEngine::Level, clang::Diagnostic const&) (/build/./bin/clang+0x22878a4) #11 0x0000000001ddf387 clang::DiagnosticIDs::ProcessDiag(clang::DiagnosticsEngine&) const (/build/./bin/clang+0x1ddf387) #12 0x0000000001dd9dea clang::DiagnosticsEngine::EmitCurrentDiagnostic(bool) (/build/./bin/clang+0x1dd9dea) #13 0x0000000002cad00c clang::Sema::EmitCurrentDiagnostic(unsigned int) (/build/./bin/clang+0x2cad00c) #14 0x0000000002d91cd2 clang::Sema::CheckShadow(clang::NamedDecl*, clang::NamedDecl*, clang::LookupResult const&) (/build/./bin/clang+0x2d91cd2) Stack dump: 0. Program arguments: /build/./bin/clang -cc1 -internal-isystem /build/lib/clang/5.0.0/include -nostdsysteminc -verify -fsyntax-only -std=c++11 -Wshadow-all /src/tools/clang/test/SemaCXX/warn-shadow.cpp 1. /src/tools/clang/test/SemaCXX/warn-shadow.cpp:214:23: current parser token ';' 2. /src/tools/clang/test/SemaCXX/warn-shadow.cpp:213:26: parsing function body 'handleLinkageSpec' 3. /src/tools/clang/test/SemaCXX/warn-shadow.cpp:213:26: in compound statement ('{}') /build/tools/clang/test/SemaCXX/Output/warn-shadow.cpp.script: line 1: 15595 Aborted (core dumped) /build/./bin/clang -cc1 -internal-isystem /build/lib/clang/5.0.0/include -nostdsysteminc -verify -fsyntax-only -std=c++11 -Wshadow-all /src/tools/clang/test/SemaCXX/warn-shadow.cpp Reviewers: rsmith Reviewed By: rsmith Subscribers: krytarowski, cfe-commits Differential Revision: https://reviews.llvm.org/D33207
rnk
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This implements suggesting other mnemonics when an invalid one is specified, for example: $ echo "adXd r1,r2,chapuni#3" | llvm-mc -triple arm <stdin>:1:1: error: invalid instruction, did you mean: add, qadd? adXd r1,r2,chapuni#3 ^ The implementation is target agnostic, but as a first step I have added it only to the ARM backend; so the ARM backend is a good example if someone wants to enable this too for another target. Differential Revision: https://reviews.llvm.org/D33128
pcc
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Oct 27, 2017
Summary: The code comments indicate that no effort has been spent on handling load/stores when the size isn't a multiple of the byte size correctly. However, the code only avoided types smaller than 8 bits. So for example a load of an i28 could still be considered as a candidate for vectorization. This patch adjusts the code to behave according to the code comment. The test case used to hit the following assert when trying to use "cast" an i32 to i28 using CreateBitOrPointerCast: opt: ../lib/IR/Instructions.cpp:2565: Assertion `castIsValid(op, S, Ty) && "Invalid cast!"' failed. #0 PrintStackTraceSignalHandler(void*) chapuni#1 SignalHandler(int) chapuni#2 __restore_rt chapuni#3 __GI_raise #4 __GI_abort #5 __GI___assert_fail #6 llvm::CastInst::Create(llvm::Instruction::CastOps, llvm::Value*, llvm::Type*, llvm::Twine const&, llvm::Instruction*) #7 llvm::IRBuilder<llvm::ConstantFolder, llvm::IRBuilderDefaultInserter>::CreateBitOrPointerCast(llvm::Value*, llvm::Type*, llvm::Twine const&) #8 (anonymous namespace)::Vectorizer::vectorizeLoadChain(llvm::ArrayRef<llvm::Instruction*>, llvm::SmallPtrSet<llvm::Instruction*, 16u>*) Reviewers: arsenm Reviewed By: arsenm Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D39295
pcc
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Oct 27, 2017
Summary: We no longer add vectors of pointers as candidates for load/store vectorization. It does not seem to work anyway, but without this patch we can end up in asserts when trying to create casts between an integer type and the pointer of vectors type. The test case I've added used to assert like this when trying to cast between i64 and <2 x i16*>: opt: ../lib/IR/Instructions.cpp:2565: Assertion `castIsValid(op, S, Ty) && "Invalid cast!"' failed. #0 PrintStackTraceSignalHandler(void*) chapuni#1 SignalHandler(int) chapuni#2 __restore_rt chapuni#3 __GI_raise #4 __GI_abort #5 __GI___assert_fail #6 llvm::CastInst::Create(llvm::Instruction::CastOps, llvm::Value*, llvm::Type*, llvm::Twine const&, llvm::Instruction*) #7 llvm::IRBuilder<llvm::ConstantFolder, llvm::IRBuilderDefaultInserter>::CreateBitOrPointerCast(llvm::Value*, llvm::Type*, llvm::Twine const&) #8 Vectorizer::vectorizeStoreChain(llvm::ArrayRef<llvm::Instruction*>, llvm::SmallPtrSet<llvm::Instruction*, 16u>*) Reviewers: arsenm Reviewed By: arsenm Subscribers: nhaehnle, llvm-commits Differential Revision: https://reviews.llvm.org/D39296
pcc
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making it no longer even remotely simple. The pass will now be more of a "full loop unswitching" pass rather than anything substantively simpler than any other approach. I plan to rename it accordingly once the dust settles. The key ideas of the new loop unswitcher are carried over for non-trivial unswitching: 1) Fully unswitch a branch or switch instruction from inside of a loop to outside of it. 2) Update the CFG and IR. This avoids needing to "remember" the unswitched branches as well as avoiding excessively cloning and reliance on complex parts of simplify-cfg to cleanup the cfg. 3) Update the analyses (where we can) rather than just blowing them away or relying on something else updating them. Sadly, chapuni#3 is somewhat compromised here as the dominator tree updates were too complex for me to want to reason about. I will need to make another attempt to do this now that we have a nice dynamic update API for dominators. However, we do adhere to chapuni#3 w.r.t. LoopInfo. This approach also adds an important principls specific to non-trivial unswitching: not *all* of the loop will be duplicated when unswitching. This fact allows us to compute the cost in terms of how much *duplicate* code is inserted rather than just on raw size. Unswitching conditions which essentialy partition loops will work regardless of the total loop size. Some remaining issues that I will be addressing in subsequent commits: - Handling unstructured control flow. - Unswitching 'switch' cases instead of just branches. - Moving to the dynamic update API for dominators. Some high-level, interesting limitationsV that folks might want to push on as follow-ups but that I don't have any immediate plans around: - We could be much more clever about not cloning things that will be deleted. In fact, we should be able to delete *nothing* and do a minimal number of clones. - There are many more interesting selection criteria for which branch to unswitch that we might want to look at. One that I'm interested in particularly are a set of conditions which all exit the loop and which can be merged into a single unswitched test of them. Differential revision: https://reviews.llvm.org/D34200
pcc
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We want to do this for 2 reasons: 1. Value tracking does not recognize the ashr variant, so it would fail to match for cases like D39766. 2. DAGCombiner does better at producing optimal codegen when we have the cmp+sel pattern. More detail about what happens in the backend: 1. DAGCombiner has a generic transform for all targets to convert the scalar cmp+sel variant of abs into the shift variant. That is the opposite of this IR canonicalization. 2. DAGCombiner has a generic transform for all targets to convert the vector cmp+sel variant of abs into either an ABS node or the shift variant. That is again the opposite of this IR canonicalization. 3. DAGCombiner has a generic transform for all targets to convert the exact shift variants produced by chapuni#1 or chapuni#2 into an ISD::ABS node. Note: It would be an efficiency improvement if we had chapuni#1 go directly to an ABS node when that's legal/custom. 4. The pattern matching above is incomplete, so it is possible to escape the intended/optimal codegen in a variety of ways. a. For chapuni#2, the vector path is missing the case for setlt with a '1' constant. b. For chapuni#3, we are missing a match for commuted versions of the shift variants. 5. Therefore, this IR canonicalization can only help get us to the optimal codegen. The version of cmp+sel produced by this patch will be recognized in the DAG and converted to an ABS node when possible or the shift sequence when not. 6. In the following examples with this patch applied, we may get conditional moves rather than the shift produced by the generic DAGCombiner transforms. The conditional move is created using a target-specific decision for any given target. Whether it is optimal or not for a particular subtarget may be up for debate. define i32 @abs_shifty(i32 %x) { %signbit = ashr i32 %x, 31 %add = add i32 %signbit, %x %abs = xor i32 %signbit, %add ret i32 %abs } define i32 @abs_cmpsubsel(i32 %x) { %cmp = icmp slt i32 %x, zeroinitializer %sub = sub i32 zeroinitializer, %x %abs = select i1 %cmp, i32 %sub, i32 %x ret i32 %abs } define <4 x i32> @abs_shifty_vec(<4 x i32> %x) { %signbit = ashr <4 x i32> %x, <i32 31, i32 31, i32 31, i32 31> %add = add <4 x i32> %signbit, %x %abs = xor <4 x i32> %signbit, %add ret <4 x i32> %abs } define <4 x i32> @abs_cmpsubsel_vec(<4 x i32> %x) { %cmp = icmp slt <4 x i32> %x, zeroinitializer %sub = sub <4 x i32> zeroinitializer, %x %abs = select <4 x i1> %cmp, <4 x i32> %sub, <4 x i32> %x ret <4 x i32> %abs } > $ ./opt -instcombine shiftyabs.ll -S | ./llc -o - -mtriple=x86_64 -mattr=avx > abs_shifty: > movl %edi, %eax > negl %eax > cmovll %edi, %eax > retq > > abs_cmpsubsel: > movl %edi, %eax > negl %eax > cmovll %edi, %eax > retq > > abs_shifty_vec: > vpabsd %xmm0, %xmm0 > retq > > abs_cmpsubsel_vec: > vpabsd %xmm0, %xmm0 > retq > > $ ./opt -instcombine shiftyabs.ll -S | ./llc -o - -mtriple=aarch64 > abs_shifty: > cmp w0, #0 // =0 > cneg w0, w0, mi > ret > > abs_cmpsubsel: > cmp w0, #0 // =0 > cneg w0, w0, mi > ret > > abs_shifty_vec: > abs v0.4s, v0.4s > ret > > abs_cmpsubsel_vec: > abs v0.4s, v0.4s > ret > > $ ./opt -instcombine shiftyabs.ll -S | ./llc -o - -mtriple=powerpc64le > abs_shifty: > srawi 4, 3, 31 > add 3, 3, 4 > xor 3, 3, 4 > blr > > abs_cmpsubsel: > srawi 4, 3, 31 > add 3, 3, 4 > xor 3, 3, 4 > blr > > abs_shifty_vec: > vspltisw 3, -16 > vspltisw 4, 15 > vsubuwm 3, 4, 3 > vsraw 3, 2, 3 > vadduwm 2, 2, 3 > xxlxor 34, 34, 35 > blr > > abs_cmpsubsel_vec: > vspltisw 3, -16 > vspltisw 4, 15 > vsubuwm 3, 4, 3 > vsraw 3, 2, 3 > vadduwm 2, 2, 3 > xxlxor 34, 34, 35 > blr > Differential Revision: https://reviews.llvm.org/D40984
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Jan 18, 2018
Summary: __builtin_clz used for Log calculation returns an undefined result when argument is 0. I noticed that issue when was testing some fuzzers: ``` /src/libfuzzer/FuzzerTracePC.h:282:33: runtime error: shift exponent 450349 is too large for 32-bit type 'uint32_t' (aka 'unsigned int') #0 0x43d83f in operator() /src/libfuzzer/FuzzerTracePC.h:283:33 chapuni#1 0x43d83f in void fuzzer::TracePC::CollectFeatures<fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool*)::$_1>(fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool*)::$_1) const /src/libfuzzer/FuzzerTracePC.h:290 chapuni#2 0x43cbd4 in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool*) /src/libfuzzer/FuzzerLoop.cpp:445:7 chapuni#3 0x43e5f1 in fuzzer::Fuzzer::ReadAndExecuteSeedCorpora(std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, fuzzer::fuzzer_allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > const&) /src/libfuzzer/FuzzerLoop.cpp:706:5 #4 0x43e9e1 in fuzzer::Fuzzer::Loop(std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, fuzzer::fuzzer_allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > const&) /src/libfuzzer/FuzzerLoop.cpp:739:3 #5 0x432f8c in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /src/libfuzzer/FuzzerDriver.cpp:754:6 #6 0x42ee18 in main /src/libfuzzer/FuzzerMain.cpp:20:10 #7 0x7f17ffeb182f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f) #8 0x407838 in _start (/out/rotate_fuzzer+0x407838) Reviewers: kcc Reviewed By: kcc Subscribers: llvm-commits, #sanitizers Differential Revision: https://reviews.llvm.org/D41457
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Summary:
I have been getting rather difficult to reproduce SIGBUS crashes when
compiling certain FreeBSD sources, and their stack traces pointed
squarely at `SelectionDAG::salvageDebugInfo()`:
```
Core was generated by `/usr/obj/share/dim/src/freebsd/clang600-import/amd64.amd64/tmp/usr/bin/cc -cc1 -'.
Program terminated with signal SIGBUS, Bus error.
#0 isInvalidated () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SDNodeDbgValue.h:115
115 bool isInvalidated() const { return Invalid; }
(gdb) bt
#0 isInvalidated () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SDNodeDbgValue.h:115
chapuni#1 salvageDebugInfo () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:7116
chapuni#2 0x00000000033b2516 in operator() () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:3595
chapuni#3 __invoke<(lambda at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:3593:59) &, llvm::SDNode *, llvm::SDNode *> () at /usr/include/c++/v1/type_traits:4323
#4 __call<(lambda at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:3593:59) &, llvm::SDNode *, llvm::SDNode *> () at /usr/include/c++/v1/__functional_base:349
#5 operator() () at /usr/include/c++/v1/functional:1562
#6 0x00000000033b0817 in operator() () at /usr/include/c++/v1/functional:1916
#7 NodeDeleted () at /share/dim/src/freebsd/clang600-import/contrib/llvm/include/llvm/CodeGen/SelectionDAG.h:293
#8 0x0000000003529dde in RemoveDeadNodes () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:610
#9 0x00000000035556df in MorphNodeTo () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:6794
#10 0x00000000033a9acc in MorphNode () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:2594
#11 0x00000000033ac80b in SelectCodeCommon () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:3601
#12 0x00000000023d464b in SelectCode () at /usr/obj/share/dim/src/freebsd/clang600-import/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/X86GenDAGISel.inc:282902
#13 Select () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp:3072
#14 0x00000000033a5afa in DoInstructionSelection () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:988
#15 0x00000000033a4e1a in CodeGenAndEmitDAG () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:868
#16 0x00000000033a2643 in SelectAllBasicBlocks () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1624
#17 0x000000000339f158 in runOnMachineFunction () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:466
#18 0x00000000023d03c4 in runOnMachineFunction () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp:175
#19 0x00000000035cc8c2 in runOnFunction () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/MachineFunctionPass.cpp:62
#20 0x00000000030dca9a in runOnFunction () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/IR/LegacyPassManager.cpp:1520
#21 0x00000000030dccf3 in runOnModule () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/IR/LegacyPassManager.cpp:1541
#22 0x00000000030dd228 in runOnModule () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/IR/LegacyPassManager.cpp:1597
#23 run () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/IR/LegacyPassManager.cpp:1700
#24 0x00000000014db578 in EmitAssembly () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/CodeGen/BackendUtil.cpp:815
#25 EmitBackendOutput () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/CodeGen/BackendUtil.cpp:1181
#26 0x00000000014d5b26 in HandleTranslationUnit () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/CodeGen/CodeGenAction.cpp:292
#27 0x0000000001c4c332 in ParseAST () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/Parse/ParseAST.cpp:159
#28 0x00000000015d546c in Execute () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/Frontend/FrontendAction.cpp:897
#29 0x0000000001cec311 in ExecuteAction () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/Frontend/CompilerInstance.cpp:991
#30 0x00000000014b4f81 in ExecuteCompilerInvocation () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:252
#31 0x00000000014aa73f in cc1_main () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/tools/driver/cc1_main.cpp:221
#32 0x00000000014b2928 in ExecuteCC1Tool () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/tools/driver/driver.cpp:309
#33 main () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/tools/driver/driver.cpp:388
(gdb) frame 1
chapuni#1 salvageDebugInfo () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:7116
7116 if (DV->isInvalidated())
(gdb) disassemble
Dump of assembler code for function salvageDebugInfo():
[...]
0x0000000003557348 <+744>: nopl 0x0(%rax,%rax,1)
0x0000000003557350 <+752>: mov (%r12),%r13
=> 0x0000000003557354 <+756>: cmpb $0x0,0x31(%r13)
0x0000000003557359 <+761>: jne 0x35573b0 <salvageDebugInfo()+848>
(gdb) info registers
[...]
r13 0x5a5a5a5a5a5a5a5a 6510615555426900570
```
The `0x5a5a5a5a5a5a5a5a` value in `r13` indicates the memory was either
uninitialized, or already freed.
Unfortunately I do not have a simple self-contained test case for this.
However, it seems pretty clear that the call to `AddDbgValue()` in
`salvageDebugInfo()` causes the problems, since it modifies
`SelectionDag::DbgInfo` while looping through one of its DenseMaps:
```
void SelectionDAG::salvageDebugInfo(SDNode &N) {
[...]
for (auto DV : GetDbgValues(&N)) {
if (DV->isInvalidated())
continue;
[...]
AddDbgValue(Clone, N0.getNode(), false);
[...]
}
}
```
At least, if I comment out the `AddDbgValue()` call, the crashes go
away. I propose to change this function slightly, similar to the
`SelectionDAG::transferDbgValues()` function just above it, to save the
cloned SDDbgValues in a separate SmallVector, and only call
AddDbgValue() on them after the for loop is done.
Reviewers: aprantl, bogner, bkramer, davide
Reviewed By: davide
Subscribers: davide, krytarowski, JDevlieghere, emaste, llvm-commits
Differential Revision: https://reviews.llvm.org/D41589
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May 22, 2018
Patch chapuni#3 from VPlan Outer Loop Vectorization Patch Series chapuni#1 (RFC: http://lists.llvm.org/pipermail/llvm-dev/2017-December/119523.html). Expected to be NFC for the current inner loop vectorization path. It introduces the basic algorithm to build the VPlan plain CFG (single-level CFG, no hierarchical CFG (H-CFG), yet) in the VPlan-native vectorization path using VPInstructions. It includes: - VPlanHCFGBuilder: Main class to build the VPlan H-CFG (plain CFG without nested regions, for now). - VPlanVerifier: Main class with utilities to check the consistency of a H-CFG. - VPlanBlockUtils: Main class with utilities to manipulate VPBlockBases in VPlan. Reviewers: rengolin, fhahn, mkuper, mssimpso, a.elovikov, hfinkel, aprantl. Differential Revision: https://reviews.llvm.org/D44338
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Jun 13, 2018
Summary:
Running sanitized 32-bit x86 programs on glibc 2.27 crashes at startup, with:
ERROR: AddressSanitizer: SEGV on unknown address 0xf7a8a250 (pc 0xf7f807f4 bp 0xff969fc8 sp 0xff969f7c T16777215)
The signal is caused by a WRITE memory access.
#0 0xf7f807f3 in _dl_get_tls_static_info (/lib/ld-linux.so.2+0x127f3)
chapuni#1 0xf7a92599 (/lib/libasan.so.5+0x112599)
chapuni#2 0xf7a80737 (/lib/libasan.so.5+0x100737)
chapuni#3 0xf7f7e14f in _dl_init (/lib/ld-linux.so.2+0x1014f)
#4 0xf7f6eb49 (/lib/ld-linux.so.2+0xb49)
The problem is that glibc changed the calling convention for the GLIBC_PRIVATE
symbol that sanitizer uses (even when it should not, GLIBC_PRIVATE is exactly
for symbols that can change at any time, be removed etc.), see
https://sourceware.org/ml/libc-alpha/2017-08/msg00497.html
Fixes google/sanitizers#954
Patch By: Jakub Jelinek
Reviewed By: vitalybuka, Lekensteyn
Differential Revison: https://reviews.llvm.org/D44623
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Jul 23, 2018
A DAG-NOT-DAG is a CHECK-DAG group, X, followed by a CHECK-NOT group,
N, followed by a CHECK-DAG group, Y. Let y be the initial directive
of Y. This patch makes the following changes to the behavior:
1. Directives in N can no longer match within part of Y's match
range just because y happens not to be the earliest match from
Y. Specifically, this patch withdraws N's search range end
from y's match range start to Y's match range start.
2. y can no longer match within X's match range, where a y match
produced a reordering complaint, which is thus no longer
possible. Specifically, this patch withdraws y's search range
start from X's permitted range start to X's match range end,
which was already the search range start for other members of
Y.
Both of these changes can only increase the number of test passes: chapuni#1
constrains the ability of CHECK-NOTs to match, and chapuni#2 expands the
ability of CHECK-DAGs to match without complaints.
These changes are based on discussions at:
<http://lists.llvm.org/pipermail/llvm-dev/2018-May/123550.html>
<https://reviews.llvm.org/D47106>
which conclude that:
1. These changes simplify the FileCheck conceptual model. First,
it makes search ranges for DAG-NOT-DAG more consistent with
other cases. Second, it was confusing that y was treated
differently from the rest of Y.
2. These changes add theoretical use cases for DAG-NOT-DAG that
had no obvious means to be expressed otherwise. We can justify
the first half of this assertion with the observation that
these changes can only increase the number of test passes.
3. Reordering detection for DAG-NOT-DAG had no obvious real
benefit.
We don't have evidence from real uses cases to help us debate
conclusions chapuni#2 and chapuni#3, but chapuni#1 at least seems intuitive.
Reviewed By: probinson
Differential Revision: https://reviews.llvm.org/D48986
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Summary:
As a bonus, this arguably improves the code by making it simpler.
gcc 8 on Ubuntu 18.10 reports the following:
==39667==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7fffffff8ae0 at pc 0x555555dbfc68 bp 0x7fffffff8760 sp 0x7fffffff8750
WRITE of size 8 at 0x7fffffff8ae0 thread T0
#0 0x555555dbfc67 in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_Alloc_hider::_Alloc_hider(char*, std::allocator<char>&&) /usr/include/c++/8/bits/basic_string.h:149
chapuni#1 0x555555dbfc67 in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&&) /usr/include/c++/8/bits/basic_string.h:542
chapuni#2 0x555555dbfc67 in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&&) /usr/include/c++/8/bits/basic_string.h:6009
chapuni#3 0x555555dbfc67 in searchableFieldType /home/nha/amd/build/san/llvm-src/utils/TableGen/SearchableTableEmitter.cpp:168
(...)
Address 0x7fffffff8ae0 is located in stack of thread T0 at offset 864 in frame
#0 0x555555dbef3f in searchableFieldType /home/nha/amd/build/san/llvm-src/utils/TableGen/SearchableTableEmitter.cpp:148
Reviewers: fhahn, simon_tatham, kparzysz
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D53931
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Nov 14, 2018
Flags variable was not initialized and later used (both isMBBSafeToOutlineFrom
implementations assume it's initialized), which breaks
test/CodeGen/AArch64/machine-outliner.mir. under memory sanitizer:
MemorySanitizer: use-of-uninitialized-value
#0 in llvm::AArch64InstrInfo::getOutliningType(llvm::MachineInstrBundleIterator<llvm::MachineInstr, false>&, unsigned int) const llvm/lib/Target/AArch64/AArch64InstrInfo.cpp:5494:9
chapuni#1 in (anonymous namespace)::InstructionMapper::convertToUnsignedVec(llvm::MachineBasicBlock&, llvm::TargetInstrInfo const&) llvm/lib/CodeGen/MachineOutliner.cpp:772:19
chapuni#2 in (anonymous namespace)::MachineOutliner::populateMapper((anonymous namespace)::InstructionMapper&, llvm::Module&, llvm::MachineModuleInfo&) llvm/lib/CodeGen/MachineOutliner.cpp:1543:14
chapuni#3 in (anonymous namespace)::MachineOutliner::runOnModule(llvm::Module&) llvm/lib/CodeGen/MachineOutliner.cpp:1645:3
#4 in (anonymous namespace)::MPPassManager::runOnModule(llvm::Module&) llvm/lib/IR/LegacyPassManager.cpp:1744:27
#5 in llvm::legacy::PassManagerImpl::run(llvm::Module&) llvm/lib/IR/LegacyPassManager.cpp:1857:44
#6 in compileModule(char**, llvm::LLVMContext&) llvm/tools/llc/llc.cpp:597:8
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Hello, can you help me and write some CFLAGS for CLang for O3 optimisation on IvyBridge / Haswell CPUs?
I use only:
-O3 -march=corei7-avx -mtune=core-avx-i -Wall
but i am intresting more info about "-mcpu" and "-march" flag:
"corei7-avx" or "core-avx-i" i need use for intel 3770k?
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