Author: Scott Gasch
Date: 14:19:21 11/27/01
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On November 27, 2001 at 16:12:24, Miguel A. Ballicora wrote: >Has anybody experienced bugs from MS Visual C 6.0 when programming in C? Yes, once. >A couple of times I have observed weird behaviors that after a lot of debugging >I had to conclude that there was something weird with the compiler or optimizer. >For instance, I include a printf() to debug part of the program and that was >never printed. It just skipped that instruction. I had no idea what it was >because I just rewrote the function to make it work. Did you try dumping the assembly generated for your function in a debugger and sanity checking it? The presence of absence of a "call _printf" should be easy to verify. Such blatant code generation bugs are rare, I think. >Most of the time I think >that I am wrong (most of the time I am wrong) but there are some things that do >not make sense. Now I am facing a problem that probably is me, but it look very >suspicious. I'll comment on that when I am sure I spent enough time on it. [snip] Would be curious to hear about it. I've found that most of the time it's a bug in my code... I have a bad habit of blaming the compiler and then digging in and finding its my own bug. That said, once I found a glaring code gen bug in MSVC once and was forced to work around it. It took me a full day of tedious debugging but the problem was in my pawn evaluation function where MSVC had generated code that used the wrong register. I was or-ing a flag into the a member of one struct and the compiler generated code using a register containing a pointer to an entirely different struct. This caused garbage in my position (board) that later caused a crash in the SEE. The problem only repeated with full optimization turned on. I ran into this when I first ported from gcc to MSVC6.0 (SP4, I think). I then took my code in to work with me where we use development versions of MSVC7.0 and the problem seems to be fixed in the newer (forthcoming) compilers. Scott
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