AntonErtl

7 ms·

1.
by AntonErtl 10y ago
However, if you leave register allocation to the source->VM compiler and don't do it in the VM->machine compiler (JIT), you cannot perform machine-specific register allocation (8 registers on IA-32, 16 on AMD64 and ARM, 32 on Aar
2.
by AntonErtl 11y ago
"Strictly conforming program" excludes implementation-defined behaviour, and AFAICS all ways to terminate a C program are implementation-defined behaviour, so terminating C programs are not strictly conforming. "C" is ac
3.
by AntonErtl 11y ago
The point of my posting was that you don't need "optimizations" to optimize away redundant bounds checks, optimization* is able to do it just fine. Sorry if I did not get that across clearly. What does your "No, it wou
4.
by AntonErtl 11y ago
I tested compiling SATD() with gcc-4.8.2 and gcc-5.2.0 with -O3, and they do not "optimize" SATD() into an infinite loop. That some version between 4.7 and 4.8 did actually do it was well publicized, and is also documented in bug
5.
by AntonErtl 11y ago
"Conforming program" may be a largely useless term, but it's one of the two conformance levels for programs that the C standard defines. The other is "strictly conforming program", and it does not include any termi
6.
by AntonErtl 11y ago
As for the market demands on compilers, I hope that this paper influences that in more reasonable directions. In the meantime, I have nothing against having an option (or more) for "optimizations". Enabling new "optimizatio
7.
by AntonErtl 11y ago
I would be pretty miffed if I wrote a, say, Pascal compilers with array bounds checks, and the compiler "optimized" the checks away just because accessing a[i] would be undefined behaviour. OTOH, in a loop like for (i=0; i<16;
8.
by AntonErtl 11y ago
The "optimization" was added and turned on by default (for some higher optimization levels) in a pre-release of gcc-4.8. After it turned out to miscompile SPEC, they disabled it for the case occuring there (it still seems to be o
9.
by AntonErtl 11y ago
A segmentation violation when doing the out-of-bounds access would be a possible behaviour of C* code. Concerning the intent: Note that the result of the out-of-bounds access is not being used. Looks to me like SATD() just produces the sum
10.
by AntonErtl 11y ago
Thank you for the interest in this paper. You read one intention of the quotes right. But they are also intended to be scare quotes; if the result of an "optimization" is equivalent to the behaviour intended by the programmer tha