[Bug c++/105278] no warning for precise literals compared with floats
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105278 --- Comment #5 from Andrew Pinski --- Note I think GCC's -Wfloat-equal is more reasonible than Clang's -Wliteral-range really. The reason is because even if something can be represented exactly in floating point (e.g. 3.0 or even 0.0), you could in theory still get a few precision mismatch due to FMA or some other slight differences in HW implementation.
[Bug c++/105278] no warning for precise literals compared with floats
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105278 --- Comment #4 from David Binderman --- (In reply to Eric Gallager from comment #3) > (In reply to David Binderman from comment #2) > > (In reply to Eric Gallager from comment #1) > > > -Wfloat-equal gets you a warning, as does -Wdouble-promotion: > > > > Thanks for that. This looks like another case where an obscure flag > > really ought to be in -Wall or at least -Wextra. > > > > I'll be adding it into my local compiler. > > Which one of them specifically do you want as part of -Wall or -Wextra? > Because the latter is listed explicitly in some documentation somewhere as > an example of a flag that would be bad to include in -Wall or -Wextra. Sorry, I should have been more clear -Wfloat-equal. I haven't looked into the pros and cons of -Wdouble-promotion. If you've got some spare time to pin down "some documentation somewhere", then that would be appreciated.
[Bug c++/105278] no warning for precise literals compared with floats
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105278 --- Comment #3 from Eric Gallager --- (In reply to David Binderman from comment #2) > (In reply to Eric Gallager from comment #1) > > -Wfloat-equal gets you a warning, as does -Wdouble-promotion: > > Thanks for that. This looks like another case where an obscure flag > really ought to be in -Wall or at least -Wextra. > > I'll be adding it into my local compiler. Which one of them specifically do you want as part of -Wall or -Wextra? Because the latter is listed explicitly in some documentation somewhere as an example of a flag that would be bad to include in -Wall or -Wextra.
[Bug c++/105278] no warning for precise literals compared with floats
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105278 --- Comment #2 from David Binderman --- (In reply to Eric Gallager from comment #1) > -Wfloat-equal gets you a warning, as does -Wdouble-promotion: Thanks for that. This looks like another case where an obscure flag really ought to be in -Wall or at least -Wextra. I'll be adding it into my local compiler.
[Bug c++/105278] no warning for precise literals compared with floats
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105278 Eric Gallager changed: What|Removed |Added CC||egallager at gcc dot gnu.org Keywords||diagnostic --- Comment #1 from Eric Gallager --- -Wfloat-equal gets you a warning, as does -Wdouble-promotion: $ /usr/local/bin/gcc -c -g -O2 -Wall -Wextra -pedantic -Wconversion -Wfloat-equal -Wdouble-promotion 105278.c 105278.c: In function 'f': 105278.c:5:15: warning: comparing floating-point with '==' or '!=' is unsafe [-Wfloat-equal] 5 | if (a == 0.1234) | ^~ 105278.c:5:15: warning: implicit conversion from 'float' to 'double' to match other operand of binary expression [-Wdouble-promotion] $
