similar to: CFI directives for callee saved registers

With the intrinsic support for ‘memcpy’ and ‘memset’ the operands also have associated alignment operands. I think that ‘memcmp’ should also provide the alignment information for each of the source operands (when statically known). In some cases this will lead to more optimal alignment aware lowering, and for targets for which unaligned access is costly or fatal, it can be lowered safely.

Can I make another suggestion: create an intrinsic for memory equality, e.g. llvm.memcmp_eq.p0i8.p0i8.i64(i8*a, i8*b, i64 len). This intrinsic would return zero if the memory regions are equal, and nonzero otherwise. However, it does NOT return any notion of "greater" or "less". Many applications require only determining equality, rather than a total ordering. Given that

Improving lowering for memcmp is definitely something we should do for all targets. Doing it in a target specific way is decidedly non-ideal. It looks like we already have some code in SelectionDAGBuilder which tries to optimize the lowering for the memcpy library call. I am a bit confused by the problem you are trying to solve. Are you specifically interested in lowering for constant

Currently on PowerPC, calls to memcmp are not expanded and are left as library calls. In certain conditions, expansion can improve performance rather than calling the library function as done for functions like memcpy, memmove, etc. This patch (https://reviews.llvm.org/D28163) is an initial implementation for PowerPC to expand memcmp when the size is an 8 byte multiple. The approach currently

My understanding is that dynamically linking should pose no problem, but I am no lawyer. On Linux, glibc is also under LGPL license, and LLVM usually links against it. (There is really no need for us to depend on libiconv. If it is deemed to risky, then I can dropped it.) From: Anton Korobeynikov <anton at korobeynikov.info> To: Kai Peter Nacke <kai.nacke at de.ibm.com> Cc:

On 19/08/2009, at 4:00 AM, Anton Korobeynikov wrote: > Hello, Nathan > >> or if it should be a configure test, which might be safer. Are there >> any x86 platforms (other than apple) that don't need PLT-indirect >> calls? > Yes, mingw. However just tweaking the define is not enough - we're not Ok, so configure might be the way to go then, maybe something

Hi! On z/OS, there is the need to convert strings from EBCDIC to UTF-8 and vice versa. Using the POSIX iconv functions has some challenges, so I created a small wrapper around this functionality to get the same result on all platforms. This functionality is required for reading and writing GOFF object files and can also be used in the frontend. I put up the code on Phabricator

On 5 September 2013 19:27, Bill Wendling <wendling at apple.com> wrote: > Hi Rafael, > > I've been staring at the CFI directives and have a question. Some background: I want to generate the compact unwind information using just the CFI directives. I *think* that this should be doable. The issue I'm facing right now is that I need to know how much the stack pointer was

Hi Rafael, I've been staring at the CFI directives and have a question. Some background: I want to generate the compact unwind information using just the CFI directives. I *think* that this should be doable. The issue I'm facing right now is that I need to know how much the stack pointer was adjusted. So when I have something like this: .cfi_startproc Lfunc_begin175:

I think this might fix the X bug... -------------- next part -------------- diff -r e698e6ee2fa1 arch/i386/kernel/entry.S --- a/arch/i386/kernel/entry.S Tue Aug 08 10:18:34 2006 -0700 +++ b/arch/i386/kernel/entry.S Tue Aug 08 10:36:17 2006 -0700 @@ -162,17 +162,17 @@ 2: popl %es; \ 2: popl %es; \ CFI_ADJUST_CFA_OFFSET -4;\ /*CFI_RESTORE es;*/\ -.section .fixup,"ax"; \ +.pushsection

I think this might fix the X bug... -------------- next part -------------- diff -r e698e6ee2fa1 arch/i386/kernel/entry.S --- a/arch/i386/kernel/entry.S Tue Aug 08 10:18:34 2006 -0700 +++ b/arch/i386/kernel/entry.S Tue Aug 08 10:36:17 2006 -0700 @@ -162,17 +162,17 @@ 2: popl %es; \ 2: popl %es; \ CFI_ADJUST_CFA_OFFSET -4;\ /*CFI_RESTORE es;*/\ -.section .fixup,"ax"; \ +.pushsection

From: David Vrabel <david.vrabel@citrix.com> In 32 bit guests, if a userspace process has %eax == -ERESTARTSYS (-512) or -ERESTARTNOINTR (-513) when it is interrupted by an event /and/ the process has a pending signal then %eip (and %eax) are corrupted when returning to the main process after handling the signal. The application may then crash with SIGSEGV or a SIGILL or it may have subtly

I'm implementing a more efficient version of the Xen iret paravirt_op, so that it can use the real iret instruction where possible. I really need to get access to per-cpu variables, so I can set the event mask state in the vcpu_info structure, but unfortunately at the point where INTERRUPT_RETURN is used in entry.S, the usermode %fs has already been restored. How would you feel if we changed

I'm implementing a more efficient version of the Xen iret paravirt_op, so that it can use the real iret instruction where possible. I really need to get access to per-cpu variables, so I can set the event mask state in the vcpu_info structure, but unfortunately at the point where INTERRUPT_RETURN is used in entry.S, the usermode %fs has already been restored. How would you feel if we changed

Even if you can't implement such an algorithm sanely, ISTM that auto-generating this code from a table (or whatever), and choosing canonical results (to avoid a fixpoint issue), rather than what seems to be hand-additions of every possible set of minimizations on three variables, is still a better solution, no? At least then you wouldn't have human errors, and a growing file that makes

<div class="socmaildefaultfont" dir="ltr" style="font-family:Arial, Helvetica, sans-serif;font-size:10.5pt" ><div dir="ltr" ><div>Hello,<br><br>I notice some strange behavior with the LegacyPassManager. I’ve added a new pass requirement of BlockFrequencyInfoWrapperPass to lib/Transforms/IPO/GlobalOpt.cpp.<br>However,

Thanks Sean for the reference. I will go through it and see if i can implement it for generic boolean expression minimization. Regards, Suyog On Wed, Aug 13, 2014 at 2:30 AM, Sean Silva <chisophugis at gmail.com> wrote: > Re-adding the mailing list (remember to hit "reply all") > > > On Tue, Aug 12, 2014 at 9:36 AM, suyog sarda <sardask01 at gmail.com> wrote:

Hi Duncan, David, Sean. Thanks for your reply. > It'd be interesting if you could find a design that also treated these > the same: > > (B ^ A) | ((A ^ B) ^ C) -> (A ^ B) | C > (B ^ A) | ((B ^ C) ^ A) -> (A ^ B) | C > (B ^ A) | ((C ^ A) ^ B) -> (A ^ B) | C > > I.e., `^` is also associative. Agree with Duncan on including associative operation too.

I've another problem. There's one register, gr6, which is used to return high part of return value for functions returning 64-bit values. For such functions, the register should not be saved, naturally. But when function does not return 64-bit value, then the register must be saved. How can I express this in .td file? - Volodya

Vladimir Prus wrote: > I've another problem. There's one register, gr6, which is used to return > high part of return value for functions returning 64-bit values. For such > functions, the register should not be saved, naturally. > > But when function does not return 64-bit value, then the register must be > saved. How can I express this in .td file? Ok, I've managed