hans added a comment.
We saw a new warning in Chromium after this, and I wasn't sure if that's
intentional:
#include <limits>
template <typename T> float foo(T input) {
if (sizeof(T) > 2) {
return 42;
} else {
constexpr float inverseMax = 1.0f / std::numeric_limits<T>::max();
return input * inverseMax;
}
}
float f() {
return foo(1);
}
$ build/bin/clang -c /tmp/a.cc
/tmp/a.cc:7:41: warning: implicit conversion from 'int' to 'float' changes
value from 2147483647 to 2147483648 [-Wimplicit-const-int-float-conversion]
7 | constexpr float inverseMax = 1.0f / std::numeric_limits<T>::max();
| ~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/tmp/a.cc:13:10: note: in instantiation of function template specialization
'foo<int>' requested here
13 | return foo(1);
| ^
1 warning generated.
Note that the branch with the conversion can be determined to not be taken
based on the template argument.
Using `if constexpr` suppresses the warning, but I'm not sure if that should
really be necessary?
(Our tracking bug is https://crbug.com/1487142)
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D155064/new/
https://reviews.llvm.org/D155064
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