https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112468
Bug ID: 112468
Summary: [14 Regression] Missed phi-opt after recent change
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: law at gcc dot gnu.org
Target Milestone: ---
This change:
commit 3f176e1adc6bc9cc2c21222d776b51d9f43cb66b (HEAD)
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.
Is causing a testsuite regression on moxie-elf. This is a scan dump failure,
so you don't need a full toolchain, just a cross compiler.
moxie-sim: gcc.dg/tree-ssa/phi-opt-24.c scan-tree-dump-not phiopt2 "if"
