public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
* [Bug target/112304] New: cinc is not being used for (small) constant @ 2023-10-31 4:48 pinskia at gcc dot gnu.org 2023-10-31 4:48 ` [Bug target/112304] " pinskia at gcc dot gnu.org ` (6 more replies) 0 siblings, 7 replies; 8+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-10-31 4:48 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112304 Bug ID: 112304 Summary: cinc is not being used for (small) constant Product: gcc Version: 14.0 Status: UNCONFIRMED Keywords: missed-optimization Severity: enhancement Priority: P3 Component: target Assignee: pinskia at gcc dot gnu.org Reporter: pinskia at gcc dot gnu.org Target Milestone: --- Target: aarch64-linux-gnu Take: ``` int f(int a) { return (a!=0)+42; } int f1(int a, int b) { return (a!=0)+b; } ``` Currently we get: ``` f: cmp w0, 0 cset w0, ne add w0, w0, 42 ret f1: cmp w0, 0 cinc w0, w1, ne ret ``` But f should really be: ``` mov w1, #42 cmp w0, #0 cinc w0, w1, ne ret ``` Because for many newer aarch64 cores the `mov` in this case is "free" and does not take up an issue slot or even the for a dual issue, the mov and cmp could be issued together. Even though it is the same # of instruction, the second case is going to be faster due to latencies. ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/112304] cinc is not being used for (small) constant 2023-10-31 4:48 [Bug target/112304] New: cinc is not being used for (small) constant pinskia at gcc dot gnu.org @ 2023-10-31 4:48 ` pinskia at gcc dot gnu.org 2023-10-31 4:51 ` pinskia at gcc dot gnu.org ` (5 subsequent siblings) 6 siblings, 0 replies; 8+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-10-31 4:48 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112304 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Last reconfirmed| |2023-10-31 Status|UNCONFIRMED |ASSIGNED --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Looking into this one next week. ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/112304] cinc is not being used for (small) constant 2023-10-31 4:48 [Bug target/112304] New: cinc is not being used for (small) constant pinskia at gcc dot gnu.org 2023-10-31 4:48 ` [Bug target/112304] " pinskia at gcc dot gnu.org @ 2023-10-31 4:51 ` pinskia at gcc dot gnu.org 2023-10-31 4:54 ` pinskia at gcc dot gnu.org ` (4 subsequent siblings) 6 siblings, 0 replies; 8+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-10-31 4:51 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112304 --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Trying 35 -> 16: 35: r95:SI=cc:CC!=0 REG_DEAD cc:CC 16: x0:SI=r95:SI+0x2a REG_DEAD r95:SI Failed to match this instruction: (set (reg/i:SI 0 x0) (plus:SI (ne:SI (reg:CC 66 cc) (const_int 0 [0])) (const_int 42 [0x2a]))) vs: Trying 9 -> 14: 9: r97:SI=cc:CC!=0+r101:SI REG_DEAD cc:CC REG_DEAD r101:SI 14: x0:SI=r97:SI REG_DEAD r97:SI Successfully matched this instruction: (set (reg/i:SI 0 x0) (plus:SI (ne:SI (reg:CC 66 cc) (const_int 0 [0])) (reg:SI 101))) ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/112304] cinc is not being used for (small) constant 2023-10-31 4:48 [Bug target/112304] New: cinc is not being used for (small) constant pinskia at gcc dot gnu.org 2023-10-31 4:48 ` [Bug target/112304] " pinskia at gcc dot gnu.org 2023-10-31 4:51 ` pinskia at gcc dot gnu.org @ 2023-10-31 4:54 ` pinskia at gcc dot gnu.org 2024-04-25 0:14 ` pinskia at gcc dot gnu.org ` (3 subsequent siblings) 6 siblings, 0 replies; 8+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-10-31 4:54 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112304 --- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Most like the following pattern's predicates should be expanded to include constants and not just registers. (define_insn "*csinc2<mode>_insn" [(set (match_operand:GPI 0 "register_operand" "=r") (plus:GPI (match_operand 2 "aarch64_comparison_operation" "") (match_operand:GPI 1 "register_operand" "r")))] s/register_operand/general_operand/ here For the second predicate. And maybe a few others. It is similar what I just did for `*cmov<mode>_insn_insv` pattern. ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/112304] cinc is not being used for (small) constant 2023-10-31 4:48 [Bug target/112304] New: cinc is not being used for (small) constant pinskia at gcc dot gnu.org ` (2 preceding siblings ...) 2023-10-31 4:54 ` pinskia at gcc dot gnu.org @ 2024-04-25 0:14 ` pinskia at gcc dot gnu.org 2024-04-25 0:18 ` pinskia at gcc dot gnu.org ` (2 subsequent siblings) 6 siblings, 0 replies; 8+ messages in thread From: pinskia at gcc dot gnu.org @ 2024-04-25 0:14 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112304 --- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Note my patch does not change the fact that we don't pull the mov outside of the loop for: ``` void f(int *a, int l) { for(int i = 0; i < l; i++) a[i]=(a[i]!=0)+42; } ``` But that is for a different issue to fix. The issue there is we have a cset/add during the (RTL) LIM and we don't pull the constant out from the add. And then we go and do the combine and found it is an cinc and then 42 becomes part of the cinc. This is pre-existing issue and most likely could be reproduce with other testcases too. ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/112304] cinc is not being used for (small) constant 2023-10-31 4:48 [Bug target/112304] New: cinc is not being used for (small) constant pinskia at gcc dot gnu.org ` (3 preceding siblings ...) 2024-04-25 0:14 ` pinskia at gcc dot gnu.org @ 2024-04-25 0:18 ` pinskia at gcc dot gnu.org 2024-04-26 17:38 ` pinskia at gcc dot gnu.org 2024-05-15 5:26 ` pinskia at gcc dot gnu.org 6 siblings, 0 replies; 8+ messages in thread From: pinskia at gcc dot gnu.org @ 2024-04-25 0:18 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112304 --- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Created attachment 58031 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58031&action=edit Patch which I am testing Once testing is finished and GCC 15 stage 1 opens up, I will submit this. ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/112304] cinc is not being used for (small) constant 2023-10-31 4:48 [Bug target/112304] New: cinc is not being used for (small) constant pinskia at gcc dot gnu.org ` (4 preceding siblings ...) 2024-04-25 0:18 ` pinskia at gcc dot gnu.org @ 2024-04-26 17:38 ` pinskia at gcc dot gnu.org 2024-05-15 5:26 ` pinskia at gcc dot gnu.org 6 siblings, 0 replies; 8+ messages in thread From: pinskia at gcc dot gnu.org @ 2024-04-26 17:38 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112304 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |patch URL| |https://gcc.gnu.org/piperma | |il/gcc-patches/2024-April/6 | |50081.html --- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Patch posted: https://gcc.gnu.org/pipermail/gcc-patches/2024-April/650081.html ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/112304] cinc is not being used for (small) constant 2023-10-31 4:48 [Bug target/112304] New: cinc is not being used for (small) constant pinskia at gcc dot gnu.org ` (5 preceding siblings ...) 2024-04-26 17:38 ` pinskia at gcc dot gnu.org @ 2024-05-15 5:26 ` pinskia at gcc dot gnu.org 6 siblings, 0 replies; 8+ messages in thread From: pinskia at gcc dot gnu.org @ 2024-05-15 5:26 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112304 --- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #6) > Patch posted: > https://gcc.gnu.org/pipermail/gcc-patches/2024-April/650081.html Maybe it should be nonmemory_operand rather than general_operand ... Or aarch64_reg_or_imm ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2024-05-15 5:26 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2023-10-31 4:48 [Bug target/112304] New: cinc is not being used for (small) constant pinskia at gcc dot gnu.org 2023-10-31 4:48 ` [Bug target/112304] " pinskia at gcc dot gnu.org 2023-10-31 4:51 ` pinskia at gcc dot gnu.org 2023-10-31 4:54 ` pinskia at gcc dot gnu.org 2024-04-25 0:14 ` pinskia at gcc dot gnu.org 2024-04-25 0:18 ` pinskia at gcc dot gnu.org 2024-04-26 17:38 ` pinskia at gcc dot gnu.org 2024-05-15 5:26 ` pinskia at gcc dot gnu.org
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).