Open llvmbot opened 14 years ago
tkremenek
commented
12 years ago Created attachment 8949 [details] Similar false positive after casting array of uint16_t to uint8_t*
I hope this belongs here, if not I apologize.
Ideally, this would be a separate bug report, but that's fine.
cloned to rdar://problem/11966749
llvmbot
commented
12 years ago Similar false positive after casting array of uint16_t to uint8_t* I hope this belongs here, if not I apologize.
llvmbot
commented
12 years ago Indeed, I can confirm that my example doesn't give an error anymore. Thanks to whoever fixed it :)
belkadan
commented
13 years ago I can't get an error for the case without floating-point involvement on ToT. For the one with, here's what I see as the main problem, or at least a low-hanging fruit: if you perform the same cast twice, you get the same result. Is there any way we can model that?
llvmbot
commented
13 years ago Minimal example not using doubles I have a similar issue, without any doubles. I am attaching a very minimal test case.
tkremenek
commented
14 years ago I think we lose the control-dependency here because 'N' is assigned a conjured value. We aren't modeling the field value because it is a double.
llvmbot
commented
14 years ago assigned to @tkremenek
Extended Description
The attached sample code comprises two versions of a short routine called 'shrink'. They should be equivalent but the second one produces a false positive 'Assigned value is garbage or undefined'. Such a warning would make sense if the value of op->npar was a volatile, but it isn't.
Thanks.
Charles
$ /Developer/usr/bin/clang -v --analyze /Users/X/Documents/clang-bug/main.c -o foo.html Apple clang version 1.5 (tags/Apple/clang-60) Target: x86_64-apple-darwin10 Thread model: posix "/Developer/usr/bin/clang" -cc1 -triple x86_64-apple-darwin10.0.0 -analyze -disable-free -disable-llvm-verifier -main-file-name main.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-check-dead-stores -analyzer-check-objc-mem -analyzer-eagerly-assume -analyzer-check-objc-methodsigs -analyzer-check-objc-unused-ivars -analyzer-output plist -w -pic-level 1 -mdisable-fp-elim -munwind-tables -target-cpu core2 -v -resource-dir /Developer/usr/lib/clang/1.5 -ferror-limit 19 -fmessage-length 103 -stack-protector 1 -fblocks -fdiagnostics-show-option -fcolor-diagnostics -o foo.html -x c /Users/X/Documents/clang-bug/main.c clang -cc1 version 1.5 based upon llvm 2.7svn hosted on x86_64-apple-darwin10
include "..." search starts here:
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/Developer/usr/lib/clang/1.5/include /usr/local/include /usr/include /System/Library/Frameworks (framework directory) /Library/Frameworks (framework directory) End of search list. /Users/X/Documents/clang-bug/main.c:16:3: warning: Assigned value is garbage or undefined t[i] = s[i]; ^ ~~~~ 1 warning generated.