[Bug target/85095] [6/7/8 Regression] worse code generated

2018-03-28 Thread jakub at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85095

--- Comment #3 from Jakub Jelinek  ---
Author: jakub
Date: Wed Mar 28 19:16:50 2018
New Revision: 258931

URL: https://gcc.gnu.org/viewcvs?rev=258931=gcc=rev
Log:
PR target/85095
* config/i386/i386.md (*add3_carry_0, *addsi3_carry_zext_0,
*sub3_carry_0, *subsi3_carry_zext_0): New patterns.

* gcc.target/i386/pr85095-1.c: New test.
* gcc.target/i386/pr85095-2.c: New test.
* gcc.c-torture/execute/pr85095.c: New test.

Added:
trunk/gcc/testsuite/gcc.c-torture/execute/pr85095.c
trunk/gcc/testsuite/gcc.target/i386/pr85095-1.c
trunk/gcc/testsuite/gcc.target/i386/pr85095-2.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/config/i386/i386.md
trunk/gcc/testsuite/ChangeLog

[Bug target/85095] [6/7/8 Regression] worse code generated

2018-03-28 Thread rguenth at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85095

Richard Biener  changed:

   What|Removed |Added

   Priority|P3  |P2

[Bug target/85095] [6/7/8 Regression] worse code generated

2018-03-27 Thread jakub at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85095

Jakub Jelinek  changed:

   What|Removed |Added

 Status|NEW |ASSIGNED
   Assignee|unassigned at gcc dot gnu.org  |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek  ---
Created attachment 43778
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43778=edit
gcc8-pr85095.patch

Untested fix.  What happens is that combine uses simplify-rtx.c which optimizes
away the useless outer (plus with const0_rtx), and we don't have a pattern that
matches that.

[Bug target/85095] [6/7/8 Regression] worse code generated

2018-03-27 Thread jakub at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85095

Jakub Jelinek  changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
   Last reconfirmed||2018-03-27
 CC||jakub at gcc dot gnu.org
  Component|ipa |target
   Target Milestone|--- |6.5
 Ever confirmed|0   |1

--- Comment #1 from Jakub Jelinek  ---
That is much more likely r230856 than Honza's change actually.
I'll have a look.