avx512vlcd-builtins.c/avx512cd-builtins.c tests sometimes crashing in stage 2 on Arm 32-bit Linux

Nobody has claimed this yet.

This presumably started with https://github.com/llvm/llvm-project/pull/163293 but it only being a second stage failure (it passes in stage 1) suggests that it is some pre-existing code generation problem.

I reproduced this today with a 2 stage build of main at `db075a8ff73f7ebe87f66680ff64fd033f374ed9`. clang 20.1.8 building a stage 1 clang, then stage 1 clang re-building clang for stage 2.

This crash does not always happen, one example of a crash is https://lab.llvm.org/buildbot/#/builders/79/builds/2531.

```
# .---command stderr------------
# | 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: /home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang -cc1 -internal-isystem /home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/lib/clang/22/include -nostdsysteminc -x c++ -flax-vector-conversions=none -ffreestanding /home/tcwg-buildbot/worker/clang-armv7-2stage/llvm/clang/test/CodeGen/X86/avx512cd-builtins.c -triple=x86_64-apple-darwin -target-feature +avx512cd -emit-llvm -o - -Wall -Werror -fexperimental-new-constant-interpreter
# | 1. /home/tcwg-buildbot/worker/clang-armv7-2stage/llvm/clang/test/CodeGen/X86/avx512cd-builtins.c:21:1 : current parser token 'static_assert'
# | #0 0x0c6f7100 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x3be7100)
# | #1 0x0c6f4664 llvm::sys::RunSignalHandlers() (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x3be4664)
# | #2 0x0c6f80cc SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
# | #3 0xf00dd6f0 __default_rt_sa_restorer ./signal/../sysdeps/unix/sysv/linux/arm/sigrestorer.S:80:0
# | #4 0x0f9a77bc clang::interp::interp__builtin_ia32_vpconflict(clang::interp::InterpState&, clang::interp::CodePtr, clang::CallExpr const*) InterpBuiltin.cpp:0:0
# | #5 0x0f986d00 clang::interp::InterpretBuiltin(clang::interp::InterpState&, clang::interp::CodePtr, clang::CallExpr const*, unsigned int) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x6e76d00)
# | #6 0x0f9dd00c clang::interp::Interpret(clang::interp::InterpState&) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x6ecd00c)
# | #7 0x0f9e1518 clang::interp::Call(clang::interp::InterpState&, clang::interp::CodePtr, clang::interp::Function const*, unsigned int) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x6ed1518)
# | #8 0x0fc74f78 clang::interp::Compiler::VisitCallExpr(clang::CallExpr const*) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x7164f78)
# | #9 0x0fc763a4 clang::interp::Compiler::visitCallArgs(llvm::ArrayRef, clang::FunctionDecl const*, bool, bool) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x71663a4)
# | #10 0x0fc74da4 clang::interp::Compiler::VisitCallExpr(clang::CallExpr const*) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x7164da4)
# | #11 0x0fc8e1d8 clang::interp::Compiler::visit(clang::Expr const*) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x717e1d8)
# | #12 0x0fc8b1d4 clang::interp::Compiler::visitExpr(clang::Expr const*, bool) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x717b1d4)
# | #13 0x0f86e690 clang::interp::EvalEmitter::interpretExpr(clang::Expr const*, bool, bool) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x6d5e690)
# | #14 0x0f8652a0 clang::interp::Context::evaluateAsRValue(clang::interp::State&, clang::Expr const*, clang::APValue&) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x6d552a0)
# | #15 0x0f7645e4 EvaluateAsRValue((anonymous namespace)::EvalInfo&, clang::Expr const*, clang::APValue&) ExprConstant.cpp:0:0
# | #16 0x0f75fb24 clang::Expr::EvaluateAsRValue(clang::Expr::EvalResult&, clang::ASTContext const&, bool) const (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x6c4fb24)
# | #17 0x0eba6224 clang::Sema::VerifyIntegerConstantExpression(clang::Expr*, llvm::APSInt*, clang::Sema::VerifyICEDiagnoser&, clang::AllowFoldKind) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x6096224)
# | #18 0x0eba31d8 clang::Sema::VerifyIntegerConstantExpression(clang::Expr*, llvm::APSInt*, unsigned int, clang::AllowFoldKind) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x60931d8)
# | #19 0x0eb12e78 clang::Sema::BuildStaticAssertDeclaration(clang::SourceLocation, clang::Expr*, clang::Expr*, clang::SourceLocation, bool) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x6002e78)
# | #20 0x0eb12cf8 clang::Sema::ActOnStaticAssertDeclaration(clang::SourceLocation, clang::Expr*, clang::Expr*, clang::SourceLocation) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x6002cf8)
# | #21 0x0e7768a8 clang::Parser::ParseStaticAssertDeclaration(clang::SourceLocation&) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x5c668a8)
# | #22 0x0e74e998 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x5c3e998)
# | #23 0x0e724f48 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x5c14f48)
# | #24 0x0e722ed8 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr&, clang::Sema::ModuleImportState&) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x5c12ed8)
# | #25 0x0e7159b0 clang::ParseAST(clang::Sema&, bool, bool) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x5c059b0)
# | #26 0x0d18130c clang::FrontendAction::Execute() (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x467130c)
# | #27 0x0d0f6420 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x45e6420)
# | #28 0x0d26ed34 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0x475ed34)
# | #29 0x0953336c cc1_main(llvm::ArrayRef, char const*, void*) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0xa2336c)
# | #30 0x0952f468 ExecuteCC1Tool(llvm::SmallVectorImpl&, llvm::ToolContext const&, llvm::IntrusiveRefCntPtr) driver.cpp:0:0
# | #31 0x0952e4cc clang_main(int, char**, llvm::ToolContext const&) (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0xa1e4cc)
# | #32 0x0953ebb4 main (/home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/clang+0xa2ebb4)
# | #33 0xf00cd7d6 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
# | #34 0xf00cd886 call_init ./csu/libc-start.c:128:20
# | #35 0xf00cd886 __libc_start_main ./csu/libc-start.c:379:
```
The stack trace is identical but for specific addresses in both cases.

I have reduced this with creduce to:
```
typedef long long a __attribute__((__vector_size__(32)));
a constexpr c(a e) { return __builtin_ia32_vpconflictdi_256(e); }
a constexpr d(a, char, a e) { return c(e); }
bool f((d({}, 5, {}), 5));
```
Compile command:
```
/home/david.spickett/build-llvm-arm-stage2/bin/clang -cc1 -internal-isystem /home/david.spickett/build-llvm-arm-stage2/lib/clang/22/include -nostdsysteminc -x c++ -flax-vector-conversions=none -ffreestanding bug.c -triple=i386-apple-darwin -target-feature +avx512vl -target-feature +avx512cd -emit-llvm -o - -Wall -Werror -fexperimental-new-constant-interpreter
```

Start with the reduced reproducer and compile command in the issue, then inspect clang::interp::interp__builtin_ia32_vpconflict and the referenced CodeGen/X86/avx512cd-builtins.c and avx512vlcd-builtins.c tests. Compare stage 1 and stage 2 behavior on Arm 32-bit Linux. Done means the reduced case and the affected tests no longer crash during constant evaluation.

Written by the indexing model from the issue text.