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From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/114810] [14 Regression] internal compiler error: in lra_split_hard_reg_for, at lra-assigns.cc:1868 (unable to find a register to spill) {*andndi3_doubleword_bmi} with -m32 -mstackrealign -O2 -mbmi -fno-exceptions -fno-plt
Date: Mon, 22 Apr 2024 20:07:07 +0000 [thread overview]
Message-ID: <bug-114810-4-yy1lHXpihT@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-114810-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114810
--- Comment #7 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Vladimir Makarov from comment #6)
> The problem is that the alternative assumes 3 DI values live simultaneously.
> This means 6 regs and we have only 6 available ones. One input reg is
> assigned to 0 another one is to 3. So we have [01]2[34]5, where regs in
> brackets are taken by the operands. Although there are still 2 regs but
> they can not be used as they are not adjacent.
>
> The one solution is to somehow penalize the chosen alternative by changing
> alternative heuristics in lra-constraints.cc. But it definitely can affect
> other targets in some unpredicted way. So the solution is too risky
> especially at this stage. Also it might be possible that there is no
> alternative with less 3 living pseudos for some different insn case.
>
> I don't see non-risky solution right now. I'll be thinking how to better
> fix this.
Please note that the insn is defined as:
(define_insn_and_split "*andn<dwi>3_doubleword_bmi"
[(set (match_operand:<DWI> 0 "register_operand" "=&r,r,r")
(and:<DWI>
(not:<DWI> (match_operand:<DWI> 1 "register_operand" "r,0,r"))
(match_operand:<DWI> 2 "nonimmediate_operand" "ro,ro,0")))
(clobber (reg:CC FLAGS_REG))]
where the problematic alternative (=&r,r,ro) allows a memory input in its
operand 2 constraint. The allocator could spill a DImode value to a stack in
advance and reload the value from the memory in this particular alternative.
next prev parent reply other threads:[~2024-04-22 20:07 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-22 17:57 [Bug target/114810] New: " kocelfc at tutanota dot com
2024-04-22 17:58 ` [Bug target/114810] " kocelfc at tutanota dot com
2024-04-22 18:22 ` jakub at gcc dot gnu.org
2024-04-22 19:10 ` ubizjak at gmail dot com
2024-04-22 19:23 ` ubizjak at gmail dot com
2024-04-22 19:31 ` [Bug rtl-optimization/114810] " ubizjak at gmail dot com
2024-04-22 19:45 ` vmakarov at gcc dot gnu.org
2024-04-22 20:07 ` ubizjak at gmail dot com [this message]
2024-04-22 21:36 ` jakub at gcc dot gnu.org
2024-04-22 21:48 ` vmakarov at gcc dot gnu.org
2024-04-22 21:56 ` jakub at gcc dot gnu.org
2024-04-23 5:53 ` ubizjak at gmail dot com
2024-04-23 6:02 ` ubizjak at gmail dot com
2024-04-23 12:29 ` jakub at gcc dot gnu.org
2024-04-23 12:46 ` ubizjak at gmail dot com
2024-04-23 21:31 ` cvs-commit at gcc dot gnu.org
2024-04-23 21:31 ` jakub at gcc dot gnu.org
2024-05-08 16:39 ` cvs-commit at gcc dot gnu.org
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