[llvm-bugs] [Bug 45327] New: Segfault during armv7 code generation for a PHINode referencing a call to llvm.frameaddress

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=45327

            Bug ID: 45327
           Summary: Segfault during armv7 code generation for a PHINode
                    referencing a call to llvm.frameaddress
           Product: libraries
           Version: 10.0
          Hardware: PC
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Common Code Generator Code
          Assignee: unassignedbugs at nondot.org
          Reporter: andrey.vihrov at gmail.com
                CC: llvm-bugs at lists.llvm.org

Consider the following LLVM IR (z.ll):
---------------------------------------------
define void @foo(i1, i8*) #0 {
E:
  br i1 %0, label %A, label %X

A:
  %a = call i8* @llvm.frameaddress(i32 0)
  br label %X

X:
  %p = phi i8* [ %a, %A ], [ %1, %E ]
  call void @bar(i8* %p)
  ret void
}

declare i8* @llvm.frameaddress(i32 immarg)

declare void @bar(i8*)

attributes #0 = { noinline optnone }
---------------------------------------------

Running
$ llc -mtriple=armv7-apple-ios z.ll
results in:

Stack dump:
0.      Program arguments: llvm-10.0.0/bin/llc -mtriple=armv7-apple-ios z.ll 
1.      Running pass 'Function Pass Manager' on module 'z.ll'.
2.      Running pass 'Live Variable Analysis' on function '@foo'
 #0 0x00007f06df2052da llvm::sys::PrintStackTrace(llvm::raw_ostream&)
(/tmp/llvm-10.0.0/bin/../lib/libLLVM-10.so+0x8532da)
 #1 0x00007f06df202f74 llvm::sys::RunSignalHandlers()
(/tmp/llvm-10.0.0/bin/../lib/libLLVM-10.so+0x850f74)
 #2 0x00007f06df2030b8 SignalHandler(int)
(/tmp/llvm-10.0.0/bin/../lib/libLLVM-10.so+0x8510b8)
 #3 0x00007f06de97a800 __restore_rt (/usr/lib/libpthread.so.0+0x14800)
 #4 0x00007f06df549ef0
llvm::LiveVariables::runOnBlock(llvm::MachineBasicBlock*, unsigned int)
(/tmp/llvm-10.0.0/bin/../lib/libLLVM-10.so+0xb97ef0)
 #5 0x00007f06df54d311
llvm::LiveVariables::runOnMachineFunction(llvm::MachineFunction&)
(/tmp/llvm-10.0.0/bin/../lib/libLLVM-10.so+0xb9b311)
 #6 0x00007f06df5c7461
llvm::MachineFunctionPass::runOnFunction(llvm::Function&)
(/tmp/llvm-10.0.0/bin/../lib/libLLVM-10.so+0xc15461)
 #7 0x00007f06df3554fa llvm::FPPassManager::runOnFunction(llvm::Function&)
(/tmp/llvm-10.0.0/bin/../lib/libLLVM-10.so+0x9a34fa)
 #8 0x00007f06df355ba1 llvm::FPPassManager::runOnModule(llvm::Module&)
(/tmp/llvm-10.0.0/bin/../lib/libLLVM-10.so+0x9a3ba1)
 #9 0x00007f06df355f39 llvm::legacy::PassManagerImpl::run(llvm::Module&)
(/tmp/llvm-10.0.0/bin/../lib/libLLVM-10.so+0x9a3f39)
#10 0x0000559e85629309 main (llvm-10.0.0/bin/llc+0x12309)
#11 0x00007f06de47e023 __libc_start_main (/usr/lib/libc.so.6+0x27023)
#12 0x0000559e8562a3ae _start (llvm-10.0.0/bin/llc+0x133ae)
Segmentation fault (core dumped)


Compiling with "-mtriple=thumbv7-apple-ios" produces the same result. At the
same time compilation succeeds with "-mtriple=aarch64-apple-ios",
"-mtriple=i386-apple-darwin" and "-mtriple=x86_64-apple-darwin". The crash is
also reproducible with "-mtriple=armv7-linux-androideabi", but not reproducible
with "-mtriple=armv7-none-eabi".

If the `llvm.frameaddress` is replaced by a different function, either regular
or another intrinsic like `llvm.returnaddress`, the error disappears. If the
`optnone` attribute is removed from the function `foo`, the error disappears.

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