mirror of
https://github.com/gcc-mirror/gcc.git
synced 2026-05-06 14:59:39 +02:00
143bb738d4
So phiprop has one disadvantage is that if there is store between the
phi with the addresses and the new load, phiprop will no do anything.
This means for some C++ code where you have a min of a max (or the opposite),
depending on the argument order of evaluation phiprop might do
the transformation or it might not (see tree-ssa/phiprop-3.C for examples).
So we need to allow skipping of one store inbetween the load and
where the phi is located.
Aggregates include a store when doing phiprop so we need to check
if there are also loads between the original store/load and the
store we are skipping. This can be added afterwards but I didn't
see aggregate case happening enough to make a big dent. I added
testcases (phiprop-{10,11}.c) to make sure cases where the load
would make a different shows up though.
changes since v1:
* v2: rewrite can_handle_load to avoid duplicated skipping store code.
PR tree-optimization/123120
PR tree-optimization/116823
gcc/ChangeLog:
* tree-ssa-phiprop.cc (phiprop_insert_phi): Add other_vuse
argument, use it instead of the vuse on the use_stmt.
(can_handle_load): Add aggregate argument. Also return the vuse
of the load/store when the insert is allowed.
Skipping over one non-modifying store for !aggregate.
(propagate_with_phi): Update call to can_handle_load
and phiprop_insert_phi.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/phiprop-8.c: New test.
* gcc.dg/tree-ssa/phiprop-9.c: New test.
* gcc.dg/tree-ssa/phiprop-10.c: New test.
* gcc.dg/tree-ssa/phiprop-11.c: New test.
* gcc.dg/tree-ssa/phiprop-12.c: New test.
* g++.dg/tree-ssa/phiprop-3.C: New test.
Signed-off-by: Andrew Pinski <andrew.pinski@oss.qualcomm.com>
This directory contains the GNU Compiler Collection (GCC). The GNU Compiler Collection is free software. See the files whose names start with COPYING for copying permission. The manuals, and some of the runtime libraries, are under different terms; see the individual source files for details. The directory INSTALL contains copies of the installation information as HTML and plain text. The source of this information is gcc/doc/install.texi. The installation information includes details of what is included in the GCC sources and what files GCC installs. See the file gcc/doc/gcc.texi (together with other files that it includes) for usage and porting information. An online readable version of the manual is in the files gcc/doc/gcc.info*. See http://gcc.gnu.org/bugs/ for how to report bugs usefully. Copyright years on GCC source files may be listed using range notation, e.g., 1987-2012, indicating that every year in the range, inclusive, is a copyrightable year that could otherwise be listed individually.