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In my +- 25 years of experience, I've encountered exactly 1 compiler bug. That cost me a full week of debug. Unfortunately, it happened during my very first yea

In my +- 25 years of experience, I've encountered exactly 1 compiler bug. That cost me a full week of debug. Unfortunately, it happened during my very first year as a developer, and that triggered sub-optimal debugging practices (ie: is that the compiler fault again?) At the end of the day, you want to optimise for debug time. There's the probability that it's a compiler/developer bug (respectively very low/very high) and the time it takes to rule it out. It's of course best NOT to start by investigating the compiler bug.

bondant 4y ago
I think it's really dependent of the domain you are working in. Some stuff is better tested than others. In my 5 years careers I found bugs (found and confirmed by compiler authors) in gfortran, xlf and pgfortran. So yes bugs in compilers are rare but sometimes you just keep running into them.
- dtech 4y ago
  those are quite niche languages though, most people use compilers which are much more widely used.
  - capitalsigma 4y ago
    Clang support for AVX-512 intrinsics is pretty broken
CameronNemo 4y ago
Yeah I was debugging an issue that was occurring in a Kubernetes environment last night... kept wanting to blame the out of date Istio version. I just could not trust it and that lack of trust stopped me from seeing the whitespace error that was in front of me the whole time...
Agingcoder 4y ago
I find several every year. Most people simply don't see compiler bugs because they don't test (and most of the time don't need to) their compilers extensively enough (by testing I mean they must build, run the generated binaries, and compare the output ).
- karamanolev 4y ago
  That sounds very weird, unless you are working 1) With with an esoteric environment that has relatively few users. 2) Have specific objectives that require a lot of edge case testing or ridiculously thorough fuzzing of the binary. 3) Go out looking for them by crafting nifty things that aren't much used. Otherwise it would imply large companies (Google-scale) experience thousands of compiler bugs per year...
  - addaon 4y ago
    > Otherwise it would imply large companies (Google-scale) experience thousands of compiler bugs per year... This seems likely to be true, from my experience. Fortunately, most compiler bugs I run into (mostly with gcc and llvm) are not code generation bugs (which can eat months of debugging), but just segfaults / rejecting correct code / other broken stuff.
    - josephg 4y ago
      I also suspect most programmers spend most of their time staying more or less on the “straight and narrow”. There’s lots of obscure features in most languages (especially in old languages like C++) that not many programmers use. These features are much more likely to have buggy edge cases in the compiler. And only a small select group of programmers will run into those bugs over and over again. Eg complex template metaprogramming - which had known broken corner cases in all C++ compilers up until a decade or so ago.
  - astrange 4y ago
    If you don't hit compiler bugs, it's mostly because you're not updating your compiler. Large companies with compiler teams want to use them, so they do update their compiler, so they will find bugs in it. Btw, what do you think this prints with clang? (Whether the answer is a compiler bug is debatable…) printf("%#x\n", 1 << 32);
    - valleyer 4y ago
      Assuming int is 32 bits wide, `1 << 32` invokes UB.

bondant 4y ago

I think it's really dependent of the domain you are working in. Some stuff is better tested than others. In my 5 years careers I found bugs (found and confirmed by compiler authors) in gfortran, xlf and pgfortran. So yes bugs in compilers are rare but sometimes you just keep running into them.

dtech 4y ago
those are quite niche languages though, most people use compilers which are much more widely used.
- capitalsigma 4y ago
  Clang support for AVX-512 intrinsics is pretty broken

CameronNemo 4y ago

Yeah I was debugging an issue that was occurring in a Kubernetes environment last night... kept wanting to blame the out of date Istio version. I just could not trust it and that lack of trust stopped me from seeing the whitespace error that was in front of me the whole time...

Agingcoder 4y ago

I find several every year. Most people simply don't see compiler bugs because they don't test (and most of the time don't need to) their compilers extensively enough (by testing I mean they must build, run the generated binaries, and compare the output ).

karamanolev 4y ago
That sounds very weird, unless you are working 1) With with an esoteric environment that has relatively few users. 2) Have specific objectives that require a lot of edge case testing or ridiculously thorough fuzzing of the binary. 3) Go out looking for them by crafting nifty things that aren't much used. Otherwise it would imply large companies (Google-scale) experience thousands of compiler bugs per year...
- addaon 4y ago
  > Otherwise it would imply large companies (Google-scale) experience thousands of compiler bugs per year... This seems likely to be true, from my experience. Fortunately, most compiler bugs I run into (mostly with gcc and llvm) are not code generation bugs (which can eat months of debugging), but just segfaults / rejecting correct code / other broken stuff.
  - josephg 4y ago
    I also suspect most programmers spend most of their time staying more or less on the “straight and narrow”. There’s lots of obscure features in most languages (especially in old languages like C++) that not many programmers use. These features are much more likely to have buggy edge cases in the compiler. And only a small select group of programmers will run into those bugs over and over again. Eg complex template metaprogramming - which had known broken corner cases in all C++ compilers up until a decade or so ago.
- astrange 4y ago
  If you don't hit compiler bugs, it's mostly because you're not updating your compiler. Large companies with compiler teams want to use them, so they do update their compiler, so they will find bugs in it. Btw, what do you think this prints with clang? (Whether the answer is a compiler bug is debatable…) printf("%#x\n", 1 << 32);
  - valleyer 4y ago
    Assuming int is 32 bits wide, `1 << 32` invokes UB.