clang crash: Assertion `LHS.getValueType() == VT && RHS.getValueType() == VT && "Cannot use select on differing types"' failed.

[shao-hua-li]

clang at -O3 crashes.

Bisected to f82c55f, which was committed by @jayfoad

Compiler explorer: https://godbolt.org/z/eexKfTxjn

% cat a.c
unsigned a;
int b, d, h, i, j, l, r;
struct m {
  long n;
  short o;
  int p;
} q;
static int *s = &q.p;
unsigned char t;
int v() {
  int c;
  if (d) {
    if (h) {
      c = j;
    } else {
        if (l)
      c = i << b;
    }
  }
  return c;
}
void w(struct m p) {}
static struct m x() {
  unsigned k;
  struct m m = {};
  w(m);
  int **u = &s;
  int **n[] = {u};
  n != 0;
  for (; m.o <= 2;) {
    int o;
    *s = 0;
    r = 0 || 8;
    for (; t <= 2; t++) {
      k = 0;
      for (; k <= 2; k++) {
        int e[] = {2, 5, 5, 7, 0, 0, 6, 5, 0};
        int f;
        for (; f < a;) {
          int g;
          if (e[f])
            break;
          f += 6;
        }
      }
      m.p = 0;
      for (; v() + r + 1 + *s + k - 4 + m.p < 1; m.p = m.p + 1)
        for (; o; o++)
          ;
    }
  }
  return m;
}
int main() { x(); }
%
% clang -w -O3 a.c
clang: /root/llvm-project/llvm/include/llvm/CodeGen/SelectionDAG.h:1237: llvm::SDValue llvm::SelectionDAG::getSelect(const llvm::SDLoc&, llvm::EVT, llvm::SDValue, llvm::SDValue, llvm::SDValue): Assertion `LHS.getValueType() == VT && RHS.getValueType() == VT && "Cannot use select on differing types"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang -gdwarf-4 -g -o /app/output.s -S --gcc-toolchain=/opt/compiler-explorer/gcc-9.2.0 -fcolor-diagnostics -fno-crash-diagnostics -w -O3 <source>
1.	<eof> parser at end of file
2.	Code generation
3.	Running pass 'Function Pass Manager' on module '<source>'.
4.	Running pass 'X86 DAG->DAG Instruction Selection' on function '@main'
 #0 0x00000000037217e8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x37217e8)
 #1 0x000000000371f4ac llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x371f4ac)
 #2 0x0000000003668058 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007f6776ecc420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #4 0x00007f677698f00b raise (/lib/x86_64-linux-gnu/libc.so.6+0x4300b)
 #5 0x00007f677696e859 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22859)
 #6 0x00007f677696e729 (/lib/x86_64-linux-gnu/libc.so.6+0x22729)
 #7 0x00007f677697ffd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
 #8 0x0000000000dc2e1f llvm::SelectionDAG::getSelect(llvm::SDLoc const&, llvm::EVT, llvm::SDValue, llvm::SDValue, llvm::SDValue) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xdc2e1f)
 #9 0x000000000469dee9 (anonymous namespace)::DAGCombiner::visitSELECT(llvm::SDNode*) DAGCombiner.cpp:0:0
#10 0x00000000046f77f8 (anonymous namespace)::DAGCombiner::visit(llvm::SDNode*) DAGCombiner.cpp:0:0
#11 0x00000000046f8805 (anonymous namespace)::DAGCombiner::combine(llvm::SDNode*) DAGCombiner.cpp:0:0
#12 0x00000000046fa06c (anonymous namespace)::DAGCombiner::Run(llvm::CombineLevel) DAGCombiner.cpp:0:0
#13 0x00000000046fc64a llvm::SelectionDAG::Combine(llvm::CombineLevel, llvm::AAResults*, llvm::CodeGenOptLevel) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x46fc64a)
#14 0x0000000004825a38 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4825a38)
#15 0x00000000048294b8 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x48294b8)
#16 0x000000000482b1b2 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (.part.0) SelectionDAGISel.cpp:0:0
#17 0x000000000231874c (anonymous namespace)::X86DAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&) X86ISelDAGToDAG.cpp:0:0
#18 0x0000000002afabd1 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
#19 0x00000000030a5b19 llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x30a5b19)
#20 0x00000000030a5d51 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x30a5d51)
#21 0x00000000030a6572 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x30a6572)
#22 0x0000000003995ed2 (anonymous namespace)::EmitAssemblyHelper::EmitAssembly(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>) BackendUtil.cpp:0:0
#23 0x0000000003996379 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3996379)
#24 0x000000000498c19f clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x498c19f)
#25 0x0000000005e89ea9 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5e89ea9)
#26 0x000000000498b388 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x498b388)
#27 0x00000000041f0b09 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x41f0b09)
#28 0x0000000004171fde clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4171fde)
#29 0x00000000042cfcae clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x42cfcae)
#30 0x0000000000bef2d6 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xbef2d6)
#31 0x0000000000be6b9a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#32 0x0000000003fce1a9 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#33 0x0000000003668504 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3668504)
#34 0x0000000003fce79f clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#35 0x0000000003f96965 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3f96965)
#36 0x0000000003f973cd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3f973cd)
#37 0x0000000003f9f2f5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3f9f2f5)
#38 0x0000000000bec77c clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xbec77c)
#39 0x0000000000ae6c91 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xae6c91)
#40 0x00007f6776970083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#41 0x0000000000be667e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xbe667e)
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
%

[llvmbot]

@llvm/issue-subscribers-backend-x86

clang at -O3 crashes.

Bisected to f82c55f, which was committed by @jayfoad

Compiler explorer: https://godbolt.org/z/eexKfTxjn

% cat a.c
unsigned a;
int b, d, h, i, j, l, r;
struct m {
  long n;
  short o;
  int p;
} q;
static int *s = &q.p;
unsigned char t;
int v() {
  int c;
  if (d) {
    if (h) {
      c = j;
    } else {
        if (l)
      c = i << b;
    }
  }
  return c;
}
void w(struct m p) {}
static struct m x() {
  unsigned k;
  struct m m = {};
  w(m);
  int **u = &s;
  int **n[] = {u};
  n != 0;
  for (; m.o <= 2;) {
    int o;
    *s = 0;
    r = 0 || 8;
    for (; t <= 2; t++) {
      k = 0;
      for (; k <= 2; k++) {
        int e[] = {2, 5, 5, 7, 0, 0, 6, 5, 0};
        int f;
        for (; f < a;) {
          int g;
          if (e[f])
            break;
          f += 6;
        }
      }
      m.p = 0;
      for (; v() + r + 1 + *s + k - 4 + m.p < 1; m.p = m.p + 1)
        for (; o; o++)
          ;
    }
  }
  return m;
}
int main() { x(); }
%
% clang -w -O3 a.c
clang: /root/llvm-project/llvm/include/llvm/CodeGen/SelectionDAG.h:1237: llvm::SDValue llvm::SelectionDAG::getSelect(const llvm::SDLoc&, llvm::EVT, llvm::SDValue, llvm::SDValue, llvm::SDValue): Assertion `LHS.getValueType() == VT && RHS.getValueType() == VT && "Cannot use select on differing types"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang -gdwarf-4 -g -o /app/output.s -S --gcc-toolchain=/opt/compiler-explorer/gcc-9.2.0 -fcolor-diagnostics -fno-crash-diagnostics -w -O3 <source>
1.	<eof> parser at end of file
2.	Code generation
3.	Running pass 'Function Pass Manager' on module '<source>'.
4.	Running pass 'X86 DAG-&gt;DAG Instruction Selection' on function '@<!-- -->main'
 #<!-- -->0 0x00000000037217e8 llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x37217e8)
 #<!-- -->1 0x000000000371f4ac llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x371f4ac)
 #<!-- -->2 0x0000000003668058 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #<!-- -->3 0x00007f6776ecc420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #<!-- -->4 0x00007f677698f00b raise (/lib/x86_64-linux-gnu/libc.so.6+0x4300b)
 #<!-- -->5 0x00007f677696e859 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22859)
 #<!-- -->6 0x00007f677696e729 (/lib/x86_64-linux-gnu/libc.so.6+0x22729)
 #<!-- -->7 0x00007f677697ffd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
 #<!-- -->8 0x0000000000dc2e1f llvm::SelectionDAG::getSelect(llvm::SDLoc const&amp;, llvm::EVT, llvm::SDValue, llvm::SDValue, llvm::SDValue) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xdc2e1f)
 #<!-- -->9 0x000000000469dee9 (anonymous namespace)::DAGCombiner::visitSELECT(llvm::SDNode*) DAGCombiner.cpp:0:0
#<!-- -->10 0x00000000046f77f8 (anonymous namespace)::DAGCombiner::visit(llvm::SDNode*) DAGCombiner.cpp:0:0
#<!-- -->11 0x00000000046f8805 (anonymous namespace)::DAGCombiner::combine(llvm::SDNode*) DAGCombiner.cpp:0:0
#<!-- -->12 0x00000000046fa06c (anonymous namespace)::DAGCombiner::Run(llvm::CombineLevel) DAGCombiner.cpp:0:0
#<!-- -->13 0x00000000046fc64a llvm::SelectionDAG::Combine(llvm::CombineLevel, llvm::AAResults*, llvm::CodeGenOptLevel) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x46fc64a)
#<!-- -->14 0x0000000004825a38 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4825a38)
#<!-- -->15 0x00000000048294b8 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x48294b8)
#<!-- -->16 0x000000000482b1b2 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&amp;) (.part.0) SelectionDAGISel.cpp:0:0
#<!-- -->17 0x000000000231874c (anonymous namespace)::X86DAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&amp;) X86ISelDAGToDAG.cpp:0:0
#<!-- -->18 0x0000000002afabd1 llvm::MachineFunctionPass::runOnFunction(llvm::Function&amp;) (.part.0) MachineFunctionPass.cpp:0:0
#<!-- -->19 0x00000000030a5b19 llvm::FPPassManager::runOnFunction(llvm::Function&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x30a5b19)
#<!-- -->20 0x00000000030a5d51 llvm::FPPassManager::runOnModule(llvm::Module&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x30a5d51)
#<!-- -->21 0x00000000030a6572 llvm::legacy::PassManagerImpl::run(llvm::Module&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x30a6572)
#<!-- -->22 0x0000000003995ed2 (anonymous namespace)::EmitAssemblyHelper::EmitAssembly(clang::BackendAction, std::unique_ptr&lt;llvm::raw_pwrite_stream, std::default_delete&lt;llvm::raw_pwrite_stream&gt;&gt;) BackendUtil.cpp:0:0
#<!-- -->23 0x0000000003996379 clang::EmitBackendOutput(clang::DiagnosticsEngine&amp;, clang::HeaderSearchOptions const&amp;, clang::CodeGenOptions const&amp;, clang::TargetOptions const&amp;, clang::LangOptions const&amp;, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr&lt;llvm::vfs::FileSystem&gt;, std::unique_ptr&lt;llvm::raw_pwrite_stream, std::default_delete&lt;llvm::raw_pwrite_stream&gt;&gt;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3996379)
#<!-- -->24 0x000000000498c19f clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x498c19f)
#<!-- -->25 0x0000000005e89ea9 clang::ParseAST(clang::Sema&amp;, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5e89ea9)
#<!-- -->26 0x000000000498b388 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x498b388)
#<!-- -->27 0x00000000041f0b09 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x41f0b09)
#<!-- -->28 0x0000000004171fde clang::CompilerInstance::ExecuteAction(clang::FrontendAction&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4171fde)
#<!-- -->29 0x00000000042cfcae clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x42cfcae)
#<!-- -->30 0x0000000000bef2d6 cc1_main(llvm::ArrayRef&lt;char const*&gt;, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xbef2d6)
#<!-- -->31 0x0000000000be6b9a ExecuteCC1Tool(llvm::SmallVectorImpl&lt;char const*&gt;&amp;, llvm::ToolContext const&amp;) driver.cpp:0:0
#<!-- -->32 0x0000000003fce1a9 void llvm::function_ref&lt;void ()&gt;::callback_fn&lt;clang::driver::CC1Command::Execute(llvm::ArrayRef&lt;std::optional&lt;llvm::StringRef&gt;&gt;, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt;&gt;*, bool*) const::'lambda'()&gt;(long) Job.cpp:0:0
#<!-- -->33 0x0000000003668504 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3668504)
#<!-- -->34 0x0000000003fce79f clang::driver::CC1Command::Execute(llvm::ArrayRef&lt;std::optional&lt;llvm::StringRef&gt;&gt;, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt;&gt;*, bool*) const (.part.0) Job.cpp:0:0
#<!-- -->35 0x0000000003f96965 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&amp;, clang::driver::Command const*&amp;, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3f96965)
#<!-- -->36 0x0000000003f973cd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt;&gt;&amp;, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3f973cd)
#<!-- -->37 0x0000000003f9f2f5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt;&gt;&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3f9f2f5)
#<!-- -->38 0x0000000000bec77c clang_main(int, char**, llvm::ToolContext const&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xbec77c)
#<!-- -->39 0x0000000000ae6c91 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xae6c91)
#<!-- -->40 0x00007f6776970083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#<!-- -->41 0x0000000000be667e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xbe667e)
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
%

[jayfoad]

Here's an IR repro:

$ cat r.ll
define i32 @main(i1 %arg) {
bb:
  br label %bb1

bb1:
  %i = phi i64 [ 0, %bb ], [ %i8, %bb1 ]
  %i2 = add i32 1, 1
  %i3 = icmp eq i32 %i2, 0
  %i4 = add i32 0, 1
  %i5 = icmp eq i32 %i4, 0
  %i6 = select i1 %arg, i1 %i5, i1 %i3
  %i7 = and i64 %i, 0
  %i8 = select i1 %i6, i64 0, i64 %i
  br label %bb1
}

$ llc a.ll
llc: /home/jayfoad2/git/llvm-project/llvm/include/llvm/CodeGen/SelectionDAG.h:1238: llvm::SDValue llvm::SelectionDAG::getSelect(const llvm::SDLoc &, llvm::EVT, llvm::SDValue, llvm::SDValue, llvm::SDValue): Assertion `LHS.getValueType() == VT && RHS.getValueType() == VT && "Cannot use select on differing types"' failed.

[RKSimon]

SelectionDAG has 17 nodes:
  t0: ch,glue = EntryToken
            t6: i8,ch = CopyFromReg t0, Register:i8 %3
          t7: i1 = truncate t6
          t4: i32,i1 = uaddo Constant:i32<0>, Constant:i32<1>
          t2: i32,i1 = uaddo Constant:i32<1>, Constant:i32<1>
        t8: i1 = select t7, t4:1, t2:1
        t11: i64,ch = CopyFromReg t0, Register:i64 %0
      t12: i64 = select t8, Constant:i64<0>, t11
    t14: ch = CopyToReg t0, Register:i64 %1, t12
  t16: ch = br t14, BasicBlock:ch<bb1 0x15033f78058>

foldSelectOfBinops isn't handling the ResNo != 0 case very well

[jayfoad]

Thanks!