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From: "vineetg at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/110748] RISC-V: optimize store of DF 0.0 Date: Fri, 21 Jul 2023 21:40:10 +0000 [thread overview] Message-ID: <bug-110748-4-L7RJo8BwyB@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-110748-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110748 --- Comment #11 from Vineet Gupta <vineetg at gcc dot gnu.org> --- There's a variation which can be optimized as well and seems non trivial to implement Now it is the negative constant -0.0 to be stored to mem. In bit notation this has a single sign bit set thus can be optimized using a bseti if rv64gc_zbs. void znd(double *d) { *d = -0.0; } void znf(float *f) { *f = -0.0; } llvm optim these to znd(double*): bseti a1, zero, 63 sd a1, 0(a0) ret znf(float*): lui a1, 0x80000 sw a1, 0(a0) ret While gcc resorts to constant pool for both lui a5,%hi(.LANCHOR0) fld fa5,%lo(.LANCHOR0)(a5) fsd fa5,0(a0) ret .set .LANCHOR0,. + 0 .LC0: .word 0 .word -2147483648
next prev parent reply other threads:[~2023-07-21 21:40 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-07-20 6:13 [Bug target/110748] New: " vineetg at gcc dot gnu.org 2023-07-20 6:15 ` [Bug target/110748] RISC-V: " vineetg at gcc dot gnu.org 2023-07-20 6:28 ` kito at gcc dot gnu.org 2023-07-20 6:33 ` kito at gcc dot gnu.org 2023-07-20 6:50 ` vineetg at gcc dot gnu.org 2023-07-20 16:07 ` pinskia at gcc dot gnu.org 2023-07-20 16:23 ` law at gcc dot gnu.org 2023-07-20 17:13 ` palmer at gcc dot gnu.org 2023-07-20 17:22 ` palmer at gcc dot gnu.org 2023-07-20 17:24 ` vineetg at gcc dot gnu.org 2023-07-20 17:38 ` vineetg at gcc dot gnu.org 2023-07-21 21:29 ` vineetg at gcc dot gnu.org 2023-07-21 21:40 ` vineetg at gcc dot gnu.org [this message] 2023-07-21 21:44 ` vineetg at gcc dot gnu.org 2023-07-21 22:51 ` pinskia at gcc dot gnu.org 2023-07-22 21:45 ` cvs-commit at gcc dot gnu.org 2023-07-28 23:22 ` vineetg at gcc dot gnu.org 2023-08-15 17:13 ` vineetg at gcc dot gnu.org
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