https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109154
--- Comment #75 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Tamar Christina <tnfch...@gcc.gnu.org>: https://gcc.gnu.org/g:3f176e1adc6bc9cc2c21222d776b51d9f43cb66b commit r14-5284-g3f176e1adc6bc9cc2c21222d776b51d9f43cb66b Author: Tamar Christina <tamar.christ...@arm.com> Date: Thu Nov 9 13:59:39 2023 +0000 middle-end: optimize fneg (fabs (x)) to copysign (x, -1) [PR109154] This patch transforms fneg (fabs (x)) into copysign (x, -1) which is more canonical and allows a target to expand this sequence efficiently. Such sequences are common in scientific code working with gradients. There is an existing canonicalization of copysign (x, -1) to fneg (fabs (x)) which I remove since this is a less efficient form. The testsuite is also updated in light of this. gcc/ChangeLog: PR tree-optimization/109154 * match.pd: Add new neg+abs rule, remove inverse copysign rule. gcc/testsuite/ChangeLog: PR tree-optimization/109154 * gcc.dg/fold-copysign-1.c: Updated. * gcc.dg/pr55152-2.c: Updated. * gcc.dg/tree-ssa/abs-4.c: Updated. * gcc.dg/tree-ssa/backprop-6.c: Updated. * gcc.dg/tree-ssa/copy-sign-2.c: Updated. * gcc.dg/tree-ssa/mult-abs-2.c: Updated. * gcc.target/aarch64/fneg-abs_1.c: New test. * gcc.target/aarch64/fneg-abs_2.c: New test. * gcc.target/aarch64/fneg-abs_3.c: New test. * gcc.target/aarch64/fneg-abs_4.c: New test. * gcc.target/aarch64/sve/fneg-abs_1.c: New test. * gcc.target/aarch64/sve/fneg-abs_2.c: New test. * gcc.target/aarch64/sve/fneg-abs_3.c: New test. * gcc.target/aarch64/sve/fneg-abs_4.c: New test.
