https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95157
Bug ID: 95157
Summary: Missing -Wtautological-compare warning
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: simon.marchi at polymtl dot ca
Target Milestone: ---
Using this code:
volatile short insn;
int main()
{
if (insn < 0 && insn > 3) {
return 1;
} else {
return 0;
}
}
clang 11 warns, but gcc doesn't:
$ gcc-10 test.c -c -Wall
$ g++-10 test.c -c -Wall
$ clang-11 test.c -c -Wall
test.c:5:16: warning: overlapping comparisons always evaluate to false
[-Wtautological-overlap-compare]
if (insn < 0 && insn > 3) {
~~~~~~~~~^~~~~~~~~~~
1 warning generated.
$ clang++-11 test.c -c -Wall
clang: warning: treating 'c' input as 'c++' when in C++ mode, this behavior is
deprecated [-Wdeprecated]
test.c:5:16: warning: overlapping comparisons always evaluate to false
[-Wtautological-overlap-compare]
if (insn < 0 && insn > 3) {
~~~~~~~~~^~~~~~~~~~~
1 warning generated.
I think -Wtautological-compare should trigger here.
