Assertion `Val == MO.getImm() && "Add/sub immediate out of range!"' with high stack alignment on arm64 windows

[efriedma-quic]

Testcase:

void g(void*);
void f() { _Alignas(8192) int x[1 << 26]; g(x); }

llvm/lib/Target/AArch64/MCTargetDesc/AArch64InstPrinter.cpp:1206: void llvm::AArch64InstPrinter::printAddSubImm(const llvm::MCInst *, unsigned int, const llvm::MCSubtargetInfo &, llvm::raw_ostream &): Assertion `Val == MO.getImm() && "Add/sub immediate out of range!"' failed.

Looks like an invalid ADDXri instruction.

CC @mstorsjo

[llvmbot]

@llvm/issue-subscribers-backend-aarch64

[mstorsjo]

Hmm, I can't seem to reproduce this? I tried with e.g. this command:

$ clang -target aarch64-windows-msvc -c repro.c -O2

This tested with a recent build from git main, from 16e61eb.

[mstorsjo]

Hmm, I can't seem to reproduce this? I tried with e.g. this command:

$ clang -target aarch64-windows-msvc -c repro.c -O2

This tested with a recent build from git main, from 16e61eb.

Nevermind, I tried with -S and I can reproduce it (irrespective of whether -O2 is set or not).

[mstorsjo]

Posted an initial fix attempt at https://reviews.llvm.org/D155447.