This is the mail archive of the mailing list for the GCC project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: gcc 3.5 integration branch proposal

On 20/01/2004, at 2:11 PM, Alexandre Oliva wrote:

On Jan 20, 2004, Geoffrey Keating <> wrote:

Err... And under what kind of logic is getting the compiler slower
not a waste of time for every GCC developer (that has to bootstrap and
test the whole thing for every patch) and user (that runs GCC to build
their own applications).

I didn't say the developer should make GCC slower.  I said the
developer should not worry about performance on *old* machines.
Performance on *new* machines is still a concern.  They are often not
the same thing.

I don't see how making GCC faster on new machines wouldn't speed things up on slower machines. Hmm... Except for refraining from recomputing stuff over and over by setting aside some memory to hold the computed value. This is fine for machines with lots of memory, but not for memory-starved machines, which are more likely to be the slow ones. But then, for a sufficiently large testcase, setting such memory aside might cause even fast and big-memory boxes to get slower.

Do you have other situations in mind?

Typically, on older, slower machines (eg. the mentioned 300Mhz StrongARM), memory accesses are relatively cheap relative to computation. Thus, on newer machines it's useful to perform some computation if this results in smaller final data structures, but this is not true on older machines.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]