https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101044
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Uros Bizjak <u...@gcc.gnu.org>: https://gcc.gnu.org/g:9f6aeb85ee87c6b4e580b6b71e26cbe99e1dab70 commit r12-1950-g9f6aeb85ee87c6b4e580b6b71e26cbe99e1dab70 Author: Uros Bizjak <ubiz...@gmail.com> Date: Thu Jul 1 10:56:32 2021 +0200 i386: Add integer nabs instructions [PR101044] The patch adds integer nabs "(NEG (ABS (...)))" instructions, adds STV conversion and adjusts STV cost calculations accordingly. When CMOV instruction is used to implement abs, the sign is determined from the preceeding operand negation, and CMOVS is used to select between negated and non-negated value. To implement nabs, just reverse the condition and emit CMOVNS instead. The STV costs are adjusted for inherent NOT of nabs insn. V2DI NOT is somehow costly operation, since it is implemented as a load of zero, followed by a SUB insn. OTOH, integer nabs with inherent NOT is relatively cheap, so some STV chains became less profitable for conversion. The patch rewrites operand scanner in compute_convert_gain to a switch and reorders case instances in general_scalar_to_vector_candidate_p to benefit from fallthroughs, and to remove special processing of andnot in the later case. gcc/ 2021-07-01 Uroš Bizjak <ubiz...@gmail.com> PR target/101044 * config/i386/i386.md (*nabs<dwi>2_doubleword): New insn_and_split pattern. (*nabs<dwi>2_1): Ditto. * config/i386/i386-features.c (general_scalar_chain::compute_convert_gain): Handle (NEG (ABS (...))) RTX. Rewrite src code scanner as switch statement. (general_scalar_chain::convert_insn): Handle (NEG (ABS (...))) RTX. (general_scalar_to_vector_candidate_p): Detect (NEG (ABS (...))) RTX. Reorder case statements for (AND (NOT (...) ...)) fallthrough. gcc/testsuite/ 2021-07-01 Uroš Bizjak <ubiz...@gmail.com> PR target/101044 * gcc.target/i386/pr101044.c: New test.
