Attaching the repro.

Deleted: cpu_x86-0f1122.c 6.5 MB

cpu_x86-0f1122.c 6.5 MB View Download

Deleted: cpu_x86-0f1122.sh 10.1 KB

cpu_x86-0f1122.sh 10.1 KB View Download

Bisection points to r329673

Somewhat reduced:

$ cat /tmp/a.c

int asm_HasCPUID(void) {
  volatile int before, after, result;
  __asm {
    pushfd
    pop eax
    mov before, eax
    xor eax, 0x00200000
    push eax
    popfd
    pushfd
    pop after
  }
  result = (before ^ after) & 0x0200000;
  return result;
}

$ build.release/bin/clang -target i686-pc-win32 -c /tmp/a.c
clang-7.0: /work/llvm.combined/llvm/tools/clang/lib/Basic/TargetInfo.cpp:450: llvm::StringRef clang::TargetInfo::getNormalizedGCCRegisterName(llvm::StringRef, bool) const: Assertion `isValidGCCRegisterName(Name) && "Invalid register passed in"' failed.
/work/llvm.combined/build.release/bin/clang-7.0(_ZN4llvm3sys15PrintStackTraceERNS_11raw_ostreamE+0x1a)[0x558ef09c948a]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN4llvm3sys17RunSignalHandlersEv+0x56)[0x558ef09c71c6]
/work/llvm.combined/build.release/bin/clang-7.0(+0x246c535)[0x558ef09c7535]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x110c0)[0x7fadb91420c0]
/lib/x86_64-linux-gnu/libc.so.6(gsignal+0xcf)[0x7fadb7cd3fcf]
/lib/x86_64-linux-gnu/libc.so.6(abort+0x16a)[0x7fadb7cd53fa]
/lib/x86_64-linux-gnu/libc.so.6(+0x2be37)[0x7fadb7ccce37]
/lib/x86_64-linux-gnu/libc.so.6(+0x2bee2)[0x7fadb7cccee2]
/work/llvm.combined/build.release/bin/clang-7.0(+0x407bd95)[0x558ef25d6d95]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang7CodeGen15CodeGenFunction11EmitAsmStmtERKNS_7AsmStmtE+0x22fe)[0x558ef0be38ae]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang7CodeGen15CodeGenFunction8EmitStmtEPKNS_4StmtEN4llvm8ArrayRefIPKNS_4AttrEEE+0x229)[0x558ef0be8b09]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang7CodeGen15CodeGenFunction28EmitCompoundStmtWithoutScopeERKNS_12CompoundStmtEbNS0_12AggValueSlotE+0x53)[0x558ef0be9053]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang7CodeGen15CodeGenFunction16EmitFunctionBodyERNS0_15FunctionArgListEPKNS_4StmtE+0x8d)[0x558ef0c2263d]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang7CodeGen15CodeGenFunction12GenerateCodeENS_10GlobalDeclEPN4llvm8FunctionERKNS0_14CGFunctionInfoE+0x246)[0x558ef0c2eea6]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang7CodeGen13CodeGenModule28EmitGlobalFunctionDefinitionENS_10GlobalDeclEPN4llvm11GlobalValueE+0x16a)[0x558ef0c5649a]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang7CodeGen13CodeGenModule20EmitGlobalDefinitionENS_10GlobalDeclEPN4llvm11GlobalValueE+0x1c1)[0x558ef0c68701]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang7CodeGen13CodeGenModule10EmitGlobalENS_10GlobalDeclE+0x478)[0x558ef0c69758]
/work/llvm.combined/build.release/bin/clang-7.0(+0x270f405)[0x558ef0c6a405]
/work/llvm.combined/build.release/bin/clang-7.0(+0x2dbac6d)[0x558ef1315c6d]
/work/llvm.combined/build.release/bin/clang-7.0(+0x2db02ad)[0x558ef130b2ad]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang8ParseASTERNS_4SemaEbb+0x1a3)[0x558ef1ae7cc3]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang13CodeGenAction13ExecuteActionEv+0x80)[0x558ef1313190]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang14FrontendAction7ExecuteEv+0x8e)[0x558ef0fb763e]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang16CompilerInstance13ExecuteActionERNS_14FrontendActionE+0x17e)[0x558ef0f7f91e]
/work/llvm.combined/build.release/bin/clang-7.0(_ZN5clang25ExecuteCompilerInvocationEPNS_16CompilerInstanceE+0x86b)[0x558ef105443b]
/work/llvm.combined/build.release/bin/clang-7.0(_Z8cc1_mainN4llvm8ArrayRefIPKcEES2_Pv+0xa08)[0x558eef196e28]
/work/llvm.combined/build.release/bin/clang-7.0(main+0x1964)[0x558eef117b74]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf1)[0x7fadb7cc12b1]
/work/llvm.combined/build.release/bin/clang-7.0(_start+0x2a)[0x558eef192d0a]
Stack dump:
0.      Program arguments: /work/llvm.combined/build.release/bin/clang-7.0 -cc1 -triple i686-pc-windows-msvc19.11.0 -emit-obj -mrelax-all -mincremental-linker-compatible -disable-free -main-file-name a.c -mrelocation-model static -mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -target-cpu pentium4 -dwarf-column-info -debugger-tuning=gdb -coverage-notes-file /work/llvm.combined/a.gcno -resource-dir /work/llvm.combined/build.release/lib/clang/7.0.0 -internal-isystem /work/llvm.combined/build.release/lib/clang/7.0.0/include -fdebug-compilation-dir /work/llvm.combined -ferror-limit 19 -fmessage-length 207 -fno-use-cxa-atexit -fms-extensions -fms-compatibility -fms-compatibility-version=19.11 -fdelayed-template-parsing -fobjc-runtime=gcc -fdiagnostics-show-option -fcolor-diagnostics -o a.o -x c /tmp/a.c 
1.      <eof> parser at end of file
2.      /tmp/a.c:2:5: LLVM IR generation of declaration 'asm_HasCPUID'
3.      /tmp/a.c:2:5: Generating code for declaration 'asm_HasCPUID'
clang-7.0: error: unable to execute command: Aborted
clang-7.0: error: clang frontend command failed due to signal (use -v to see invocation)
clang version 7.0.0 
Target: i686-pc-windows-msvc
Thread model: posix
InstalledDir: /work/llvm.combined/build.release/bin
clang-7.0: note: diagnostic msg: PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace, preprocessed source, and associated run script.
clang-7.0: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-7.0: note: diagnostic msg: /tmp/a-fe8be0.c
clang-7.0: note: diagnostic msg: /tmp/a-fe8be0.sh
clang-7.0: note: diagnostic msg: 

********************

More reduced:

$ cat /tmp/a.c
void f(void) {
  __asm {
    popfd
  }
}


popfd doesn't any operands, so not sure why it's complaining..

clang::TargetInfo::getNormalizedGCCRegisterName is getting called with "DF" as register name.

isValidGCCRegisterName() is based on a list of registers in lib/Basic/Targets/X86.cpp

DF isn't there, but neither is EFLAGS. What's going on...

Oh wait, EFLAGS is listed in GCCRegNames, but just as "flags".

The reason DF shows up is that it's now a clobbered register for popf.

So, maybe just adding it to GCCRegNames is the thing? But actually, "dirflag" is already listed there. Hmm.

list says "fixed in r329734"