efriedma added inline comments.
================
Comment at: clang/lib/Frontend/TextDiagnostic.cpp:1121-1138
+static unsigned getNumDisplayWidth(unsigned N) {
+ if (N < 10)
+ return 1;
+ if (N < 100)
+ return 2;
+ if (N < 1'000)
+ return 3;
----------------
aaron.ballman wrote:
> jrtc27 wrote:
> > kwk wrote:
> > > This function screamed at me to be generalized so I gave it a try:
> > > https://gist.github.com/kwk/7e408065ea291e49fea4a83cf90a9cdf
> > I don't think I want floating point arithmetic in my compiler... Something
> > like:
> >
> > ```
> > unsigned L, M;
> > for (L = 1U, M = 10U; N >= M && M != ~0U; ++L)
> > M = (M > ((~0U) / 10U)) ? (~0U) : (M * 10U);
> >
> > return (L);
> > ```
> >
> > is the generalised form (without all the redundant parentheses I added
> > during debugging).
> Cleaned up a bit:
> ```
> constexpr unsigned getNumDisplayWidth(unsigned N) {
> unsigned L = 1U, M = 10U;
> constexpr unsigned Upper = ~0U / 10U;
> for (; N >= M && M != ~0U; ++L)
> M = M > Upper ? ~0U : M * 10U;
> return L;
> }
> ```
> https://godbolt.org/z/szTYsEM4v
Slightly less efficient, but easier to read:
```
unsigned getNumDisplayWidth(unsigned N) {
unsigned Width = 1;
for (; N >= 10; ++Width)
N /= 10;
return Width;
}
```
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D147875/new/
https://reviews.llvm.org/D147875
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
