[Bug libgcc/77273] New: 1 << 31 is undefined in gcc/config/i386/cpuid.h:93

[zeccav at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77273

            Bug ID: 77273
           Summary: 1 << 31 is undefined in gcc/config/i386/cpuid.h:93
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: libgcc
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zeccav at gmail dot com
  Target Milestone: ---

While compiling gcc itself, the sanitizer complains as follows:

gcc-trunk-239276/libgcc/config/i386/cpuinfo.c:346:17: runtime error: left shift
of 1 by 31 places cannot be represented in type 'int'

cpuinfo.c:346 is "if (ebx & bit_AVX512VL)"

bit_AVX512VL is defined in cpuid.h:249 as

#define bit_AVX512VL    (1 << 31)

I believe 1 << 31 is undefined, because "1" is int,
it should be 1u << 31 or 1U << 31

cpuid.h:66 is "#define bit_3DNOW       (1 << 31)" by the way