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From: "xry111 at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/109035] meaningless memory store on RISC-V and LoongArch
Date: Wed, 08 Mar 2023 03:37:29 +0000	[thread overview]
Message-ID: <bug-109035-4-OK23DFZVJI@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-109035-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109035

--- Comment #3 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
(In reply to chenglulu from comment #2)
> I think this is most likely caused by the implementation of the public code.

Agree, so I filled the component as rtl-optimization.

I tracked a (non root) cause to the line 1944 in ira-costs.cc:

          if (i >= first_moveable_pseudo && i < last_moveable_pseudo)
            i_mem_cost = 0;
          else if (equiv_savings < 0)
            i_mem_cost = -equiv_savings;
          else if (equiv_savings > 0)
            {
              i_mem_cost = 0;    // <====== HERE
              for (k = cost_classes_ptr->num - 1; k >= 0; k--)
                i_costs[k] += equiv_savings;
            }

I don't really understand why we should prefer the memory if there is a
REG_EQUIV note, nor why this does not happen with -fPIE.

  parent reply	other threads:[~2023-03-08  3:37 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-06  7:51 [Bug rtl-optimization/109035] New: " xry111 at gcc dot gnu.org
2023-03-06  7:52 ` [Bug rtl-optimization/109035] " xry111 at gcc dot gnu.org
2023-03-06  8:02 ` xry111 at gcc dot gnu.org
2023-03-08  3:16 ` chenglulu at loongson dot cn
2023-03-08  3:37 ` xry111 at gcc dot gnu.org [this message]
2023-03-08  3:55 ` chenglulu at loongson dot cn
2023-03-11  6:44 ` chenglulu at loongson dot cn
2023-03-11  7:00 ` chenglulu at loongson dot cn
2023-11-02 19:25 ` vmakarov at gcc dot gnu.org
2023-11-02 19:47 ` law at gcc dot gnu.org
2023-11-03  6:52 ` xry111 at gcc dot gnu.org
2023-11-03  7:46 ` xry111 at gcc dot gnu.org

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