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[Bug target/29776] result of ffs/clz/ctz/popcount/parity are already sign-extended
- From: "joseph at codesourcery dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 04 Jul 2013 19:15:43 +0000
- Subject: [Bug target/29776] result of ffs/clz/ctz/popcount/parity are already sign-extended
- Auto-submitted: auto-generated
- References: <bug-29776-4 at http dot gcc dot gnu dot org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29776
--- Comment #13 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
For the RTL operations and optabs, we have CLZ_DEFINED_VALUE_AT_ZERO and
CTZ_DEFINED_VALUE_AT_ZERO, but as noted in the documentation they do not
refer to definedness for the built-in functions. (That's similar to
SHIFT_COUNT_TRUNCATED / TARGET_SHIFT_TRUNCATION_MASK, which again describe
semantics at the RTL level but do not affect the undefinedness of
out-of-range shifts in C/C++ source code or GIMPLE.)