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| author | Richard Smith <richard-llvm@metafoo.co.uk> | 2012-08-25 00:32:28 +0000 |
|---|---|---|
| committer | Richard Smith <richard-llvm@metafoo.co.uk> | 2012-08-25 00:32:28 +0000 |
| commit | 3e056dea1bea121835ad4471ef490282855ee710 (patch) | |
| tree | 20a07ac10dc057b7ee8dab0888e41151cfbb4319 /clang/docs/UsersManual.html | |
| parent | c5041918dda38fbb480ce73da2784ae4765171d3 (diff) | |
| download | bcm5719-llvm-3e056dea1bea121835ad4471ef490282855ee710.tar.gz bcm5719-llvm-3e056dea1bea121835ad4471ef490282855ee710.zip | |
-fcatch-undefined-behavior: add the -ftrapv checks to the set of things caught
by this mode, and also check for signed left shift overflow. The rules for the
latter are a little subtle:
* neither C89 nor C++98 specify the behavior of a signed left shift at all
* in C99 and C11, shifting a 1 bit into the sign bit has undefined behavior
* in C++11, with core issue 1457, shifting a 1 bit *out* of the sign bit has
undefined behavior
As of this change, we use the C99 rules for all C language variants, and the
C++11 rules for all C++ language variants. Once we have individual
-fcatch-undefined-behavior= flags, this should be revisited.
llvm-svn: 162634
Diffstat (limited to 'clang/docs/UsersManual.html')
0 files changed, 0 insertions, 0 deletions
