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Regehr: GCC 4.8 Breaks Broken SPEC 2006 BenchmarksRegehr: GCC 4.8 Breaks Broken SPEC 2006 BenchmarksPosted Apr 2, 2013 17:30 UTC (Tue) by hummassa (subscriber, #307)In reply to: Regehr: GCC 4.8 Breaks Broken SPEC 2006 Benchmarks by hummassa Parent article: Regehr: GCC 4.8 Breaks Broken SPEC 2006 Benchmarks
I am answering to my own comments in this subthread, and it really feels like I am losing my mind... :-D for(auto x: d) satd += abs(x);and
auto satd = accumulate(begin(d), end(d), 0, [](int a, int x) { return a+abs(x); });
generated the same code, roughly:movl (%rax), %edx movl (%rax), %ecx addq $4, %rax sarl $31, %edx xorl %edx, %ecx subl %edx, %ecx leaq 64(%rsp), %r addl %ecx, %ebx cmpq %rax, %rdx jne .L3 #,which seemed nice to me.
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Regehr: GCC 4.8 Breaks Broken SPEC 2006 Benchmarks Posted Apr 2, 2013 19:17 UTC (Tue) by jwakely (subscriber, #60262) [Link]
You know GCC doesn't have a -O4 optimisation level, right? ;)
Regehr: GCC 4.8 Breaks Broken SPEC 2006 Benchmarks Posted Apr 2, 2013 20:08 UTC (Tue) by nix (subscriber, #2304) [Link]
I've seen people use -O4, -O6, -O64 ("it's a nice round number and higher than 3" he said, so at least he knew what he was aiming for), and of course glibc, of all things, used -O99 for donkey's years. GCC obviously needs an "-Olots" for these people.
Regehr: GCC 4.8 Breaks Broken SPEC 2006 Benchmarks Posted Apr 2, 2013 22:56 UTC (Tue) by jwakely (subscriber, #60262) [Link]
It should be called -Over9000 though
Regehr: GCC 4.8 Breaks Broken SPEC 2006 Benchmarks Posted Apr 2, 2013 21:18 UTC (Tue) by hummassa (subscriber, #307) [Link]
It's on my default makefile since forever, because clang does not like -O5 and beyond and I am too lazy to look up which is the biggest effective level for each compiler...
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