| commit | 07527e3eabb00ada0e7c9e083084e4e56d97f34f | |
| author | Hans-Peter Nilsson <hp@axis.com> | |
| Tue, 18 Apr 2023 17:37:21 +0000 (18 19:37 +0200) | ||
| committer | Hans-Peter Nilsson <hp@bitrange.com> | |
| Fri, 5 May 2023 23:10:37 +0000 (6 01:10 +0200) | ||
| tree | 12b8a30b840cb9ff276061fdd3b11dafc6c47403 | treesnapshot (tar.gz zip) |
| parent | 185da7c2014ba41f38dd62cc719873ebf020b076 | commitdiff |
doc: Document order of define_peephole2 scanning
I was a bit surprised when my newly-added define_peephole2 didn't
match, but it was because it was expected to partially match the
generated output of a previous define_peephole2, which matched and
modified the last insn of a sequence to be matched. I had assumed
that the algorithm backed-up the size of the match-buffer, thereby
exposing newly created opportunities *with sufficient context* to all
define_peephole2's. While things can change in that direction, let's
start with documenting the current state.
* doc/md.texi (define_peephole2): Document order of scanning.
I was a bit surprised when my newly-added define_peephole2 didn't
match, but it was because it was expected to partially match the
generated output of a previous define_peephole2, which matched and
modified the last insn of a sequence to be matched. I had assumed
that the algorithm backed-up the size of the match-buffer, thereby
exposing newly created opportunities *with sufficient context* to all
define_peephole2's. While things can change in that direction, let's
start with documenting the current state.
* doc/md.texi (define_peephole2): Document order of scanning.
| gcc/doc/md.texi | diffblobblamehistory |