similar to: LLVM backend -- Avoid base+index address mode for X86

Hi Bruce, Thanks for you reply. I check the *.td files under the lib/Target/X86 folder, but have not got interesting findings. It requires some knowledge of LLVM backend to fully understand the *.td files. I will get some background and keep searching. Of course I appreciate if anyone with such experience can point the concrete locations. Regards, Hu Hong On 17 October 2016 at 22:20, Bruce

I'm tracking down an X86 code generation malfeasance regarding BT (bit test) and I have some questions. This IR *matches* and then *X86TargetLowering::LowerToBT **is called:* %and = and i64 %shl, %val * ; (val & (1 << index)) != 0 ; *bit test with a *register* index This IR *does not match* and so *X86TargetLowering::LowerToBT **is not called:* %and = lshr i64 %val, 25

Andres: FWIW, codegen will do the merge if you turn on global alias analysis for it "-combiner-global-alias-analysis". That said, we should be able to do this merging earlier. -Nirav On Mon, Sep 10, 2018 at 8:33 PM, Andres Freund via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Hi, > > On 2018-09-10 13:42:21 -0700, Andres Freund wrote: > > I have, in postres,

Hi Scott, Sorry for the late reply, I was out of office during the holidays. 1. A def node can reach either a use node, or another def node. In the highlighted phi node (p3224), the def (d3225) reaches another def (1598) in statement (s1597), that’s why it’s needed. 2. The reason why the def of R11 in s1578 is not connected directly to the use in s1725 is that there may be an intervening

The attached .ll files seem equivalent, but the resulting asm from 'opt-fail.ll' causes a crash to webkit. I suspect the usage of registers is wrong, can someone take a look ? $ llc opt-pass.ll -o - .section __TEXT,__text,regular,pure_instructions .globl __ZN7WebCore6kolos1ERiS0_PKNS_20RenderBoxModelObjectEPNS_10StyleImageE .align 4, 0x90

Hello, I am experiencing problems, when trying to assemble these two x86-64 Opcodes "add r64, imm32" "imul r64, r64, imm32" When having the most significant bit set for imm32, for example: "add rax, 0x80000000", "add rax, 0xffffffff", ... "imul rbx, rsi, 0x80000000", "imul rbx, rsi, 0xffffffff", ... The Error Message I receive is the

On Sep 1, 2010, at 6:25 AM, Argyrios Kyrtzidis wrote: > The attached .ll files seem equivalent, but the resulting asm from 'opt-fail.ll' causes a crash to webkit. > I suspect the usage of registers is wrong, can someone take a look ? The difference is that there is a shift right after the multiply, before the divide. In IR, the difference is: %5 = mul nsw i32 %4, %tmp1

This was set to zero immediately before the #GP injection code, since SYSENTER doesn''t really have a return address. Reported-by: Ian Campbell <Ian.Campbell@citrix.com> Furthermore, UREGS_cs and UREGS_rip don''t need to be written a second time, as the PUSHes above already can/do take care of putting in place the intended values. Signed-off-by: Jan Beulich

This set of patches converts the way frames gets created from using PUSHes/POPs to using MOVes, thus allowing (in certain cases) to avoid saving/restoring part of the register set. While the place where the (small) win from this comes from varies between CPUs, the net effect is a 1 to 2% reduction on a combined interruption entry and exit when the full state save can be avoided. 1: use MOV

https://bugs.freedesktop.org/show_bug.cgi?id=28763 Summary: Kernel Oops when displaying a large image Product: xorg Version: unspecified Platform: Other OS/Version: All Status: NEW Severity: normal Priority: medium Component: Driver/nouveau AssignedTo: nouveau at lists.freedesktop.org

I'm not sure exactly what you're after. I was under the impression that you want to know which register is live at a specific point (an instruction). If that's the case, how do one of the two suggested solutions not suffice? If a register is live-in to a block and not killed before your instruction or it has a def and no kill within the block, it is live. Otherwise it is dead and

Oh duh, it used datastack pool. Try again with the attached patch? Please remember to clear the previous one out before trying. Aki > > The trace is missing some symbols, I will debug tomorrow and see where > the call comes from exactly. > > Regards, > > > On 10/17/2016 06:23 PM, Aki Tuomi wrote: > > Hi! > > > > Looking at the code, I think the bug

Sure. Attached is the file but here are the functions. The first uses a fixed bit offset. The second has a indexed bit offset. Compiling with llc -O3, LLVM version 3.7.0svn, it compiles the IR from IsBitSetB() using btq %rsi, %rdi. Good. But then it compiles IsBitSetA() with shrq/andq, which is is pretty much what Clang had generated as IR. shrq $25, %rdi andq $1, %rdi LLVM should be able to

On Fri, 18 Oct 2013 00:11:15 +0400 Eugene Shatokhin <euspectre at gmail.com> wrote: > Hi, > > Good to know that! > > Yes, it should be faster than page faulting, although I haven't done the > benchmarking yet. And yes, it is not needed to disable all but one CPU. In > my current implementation, I use an ordered workqueue to send the data to > the mmapped output

> Anyway, thanks very much for the information. Hopefully that'll let me > track things down. Let me know if you need some more information or dumps. > Would you mind me taking a day or so to investigate what's going on > here properly? Introducing a volatile to work around a bug in Clang > itself just seems perverse to me. (And we shouldn't let a CodeGen bug >

There is also the LivePhysReg facility that I would recomment if you just want to query for a free register and do not need the full feature set of the RegisterScavenger. - Matthias > On Jan 19, 2017, at 5:50 AM, Nemanja Ivanovic via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > I believe what you're after is the register scavenger. > It's in:

Accept the DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK() family of modifiers to handle broken userspace Xorg modesetting and Mesa drivers. Tested with Xorg 1.20 modesetting driver, weston at c46c70dac84a4b3030cd05b380f9f410536690fc, gnome & KDE wayland desktops from Ubuntu 18.04, and sway 1.5 Signed-off-by: James Jones <jajones at nvidia.com> --- drivers/gpu/drm/nouveau/nouveau_display.c | 26

https://bugs.freedesktop.org/show_bug.cgi?id=98506 Bug ID: 98506 Summary: Pagefault in gf100_vm_flush Product: xorg Version: git Hardware: Other OS: All Status: NEW Severity: normal Priority: medium Component: Driver/nouveau Assignee: nouveau at lists.freedesktop.org

I submitted the problem report to clang's bugzilla but no one seems to care so I have to send it to the mailing list. clang 3.7 svn (trunk 229055 as the time I was to report this problem) generates slower code than 3.5 (Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)) for the following code. It is a "8 queens puzzle" solver written as an educational example. As

https://bugs.freedesktop.org/show_bug.cgi?id=93557 Bug ID: 93557 Summary: Kernel Panic on Linux Kernel 4.4 when loading KDE/KDM on Nvidia GeForce 7025 / nForce 630a Product: xorg Version: unspecified Hardware: x86-64 (AMD64) OS: Linux (All) Status: NEW Severity: blocker