On Sat, Dec 16, 2023 at 4:19 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > We actually noticed this or a closely-related problem before [1] > and briefly discussed the possibility of rearranging the generated > code to make it less indigestible to clang. But there was no concrete > idea about what to do specifically, and the thread slid off the radar > screen.
I've never paid attention to the output of -ftime-report before but this difference stands out pretty clearly with clang16: ---User Time--- --System Time-- --User+System-- ---Wall Time--- --- Name --- 201.2266 ( 99.6%) 0.0074 ( 99.3%) 201.2341 ( 99.6%) 207.1308 ( 99.6%) SLPVectorizerPass The equivalent line for clang15 is: 3.0979 ( 64.8%) 0.0000 ( 0.0%) 3.0979 ( 64.8%) 3.0996 ( 64.8%) SLPVectorizerPass The thing Andres showed in that other thread was like this (though in my output it's grown "#2") which is much of the time in 15, but "only" goes up by a couple of seconds in 16, so it's not our primary problem: 9.1890 ( 73.1%) 0.0396 ( 23.9%) 9.2286 ( 72.4%) 9.6586 ( 72.9%) Greedy Register Allocator #2
