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…ts on riscv64 On RISC-V the JAL and JALR instructions provide Return Address Stack(RAS) prediction hints based on the registers used (as per section 2.5.1 of the RISC-V ISA manual). When a JALR instruction uses X1 or X5 as the source register, it hints that a pop should occur. When making a function call, avoid the use of X5 as a source register since this results in the RAS performing a pop-then-push instead of a push, breaking call/return pairing and significantly degrading front-end branch prediction performance. Based on test result of golang.org/x/benchmarks/json on SpacemiT K1, fix version has a performance improvement of about 7% Fixes golang#76654 Change-Id: I867c8d7cfb54f5decbe176f3ab3bb3d78af1cf64 Reviewed-on: https://go-review.googlesource.com/c/go/+/726760 Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Joel Sing <joel@sing.id.au> Run-TryBot: Joel Sing <joel@sing.id.au>
This CL implements hardware frame pointer support for riscv64. The stack layout is similar to arm64, but with the following specifics: - The FP register points to SP+8. - The return address (LR) is stored at SP. - The caller's FP is stored at SP-8. Change-Id: I3bc7af2abb024ea0b0e3432ed517641c6707f7a2
lxq015
marked this pull request as draft
June 29, 2026 02:56
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