floating point isnan might have issues

[ZERICO2005]

Fine on -Oz, but breaks at -O0

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <math.h>
#include <assert.h>
#include <ti/screen.h>
#include <ti/getcsc.h>
#include <sys/util.h>
#include <ti/sprintf.h>

#if 1
#define test_printf printf
#else
#define test_printf(...)
#endif

#include "f32_fminmax_LUT.h"

#define ARRAY_LENGTH(x) (sizeof(x) / sizeof(x[0]))

typedef union F32_pun {
    float flt;
    uint32_t bin;
} F32_pun;

size_t run_test(void) {
    typedef struct { F32_pun x; F32_pun y; } input_t;
    typedef struct { F32_pun f_min; F32_pun f_max; } output_t;

    const size_t length = ARRAY_LENGTH(f32_fminmax_LUT_input);
    const input_t  *input  = (const input_t* )((const void*)f32_fminmax_LUT_input );
    const output_t *output = (const output_t*)((const void*)f32_fminmax_LUT_output);

    for (size_t i = 0; i < length; i++) {
        F32_pun f_min;
        F32_pun f_max;
        f_min.flt = fminf(input[i].x.flt, input[i].y.flt);
        f_max.flt = fmaxf(input[i].x.flt, input[i].y.flt);

        if (f_min.bin != output[i].f_min.bin || f_max.bin != output[i].f_max.bin) {
            if (
                !(
                    isnan(f_min.flt) && isnan(output[i].f_min.flt) &&
                    isnan(f_max.flt) && isnan(output[i].f_max.flt)
                )
            ) {
                test_printf(
                    "%zu:\nI: %08lX : %08lX\nG: %08lX < %08lX\nT: %08lX < %08lX\n",
                    i,
                    input[i].x.bin, input[i].y.bin,
                    f_min.bin, f_max.bin,
                    output[i].f_min.bin, output[i].f_max.bin
                );
                return i;
            }
        }
    }

    /* passed all */
    return SIZE_MAX;
}

#ifdef __cplusplus
extern "C" {
    int main(void);
}
#endif /* __cplusplus */

int main(void) {
    os_ClrHome();
    size_t fail_index = run_test();
    if (fail_index == SIZE_MAX) {
        puts("All tests passed");
    } else {
        char buf[sizeof("Failed test: 16777215")];
        boot_sprintf(buf, "Failed test: %u", fail_index);
        puts(buf);
    }

    while (!os_GetCSC());

    return 0;
}

$ make
fatal error: error in backend: unable to legalize instruction: %9:_(s1) = G_IS_FPCLASS %8:_(s32), 3 (in
      function: _ZNSt3__16__math5isnanB8nn190107Ef)
PLEASE submit a bug report to https://github.com/CE-Programming/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: C:\\Users\\zerico\\Programming\\ez80\\toolchain\\CEdev\\bin\\ez80-clang.exe -S -mllvm -profile-guided-section-prefix=false -mllvm -z80-gas-style -ffunction-sections -fdata-sections -fno-addrsig -fno-autolink -fno-threadsafe-statics -Wall -Wextra -Wshadow -Wformat=2 -Wconversion -Wimplicit-float-conversion -Wimplicit-int-float-conversion -O0 -ffreestanding -std=c17 C:/Users/zerico/Programming/ez80/toolchain/test/floating_point/float32_fminmax/obj/lto.bc -o C:/Users/zerico/Programming/ez80/toolchain/test/floating_point/float32_fminmax/obj/lto.s
1.      Code generation
2.      Running pass 'Function Pass Manager' on module 'C:/Users/zerico/Programming/ez80/toolchain/test/floating_point/float32_fminmax/obj/lto.bc'.
3.      Running pass 'Legalizer' on function '@_ZNSt3__16__math5isnanB8nn190107Ef'
Exception Code: 0xE0000046
0x75722404, C:\WINDOWS\System32\KERNELBASE.dll(0x00000000755C0000) + 0x162404 byte(s), RaiseException() + 0x64 byte(s)
0x007837D6, C:\Users\zerico\Programming\ez80\toolchain\CEdev\bin\ez80-clang.exe(0x00000000004D0000) + 0x2B37D6 byte(s)
0x01000000, C:\Users\zerico\Programming\ez80\toolchain\CEdev\bin\ez80-clang.exe(0x00000000004D0000) + 0xB30000 byte(s)
0x049D0100 <unknown module>
ez80-clang: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 17.0.6 (https://github.com/CE-Programming/llvm-project 262d0ad4ac4c788b0e865b638c397598e797c12c)
Target: ez80
Thread model: posix
InstalledDir: C:\Users\zerico\Programming\ez80\toolchain\CEdev\bin
ez80-clang: note: diagnostic msg: Error generating preprocessed source(s) - no preprocessable inputs.
mingw32-make: *** [C:\Users\zerico\Programming\ez80\toolchain\CEdev\meta\makefile.mk:445: obj/lto.s] Error 1