search for: o0

Hello, I m trying to test individual O3 optimizations/ replicating O3 behavior on IR. I took unoptimized IR (O0), used disable-o0-optnone via (*clang -O0 -Xclang -disable-O0-optnone*). I read somewhere about *clang -O1 -Xclang -disable-O0-optnone,* so I also tested on this initial IR. I have observed by using individual optimizations, the performance (i.e time) is better when the base/initial IR is genera...

Hello Xerxes, > llvm 2.9rc1 test on Dualcore ARM running Ubuntu Natty What is the gcc used for the compilation? Can you try to do the -O0 build and see whether this changed the stuff? -- With best regards, Anton Korobeynikov Faculty of Mathematics and Mechanics, Saint Petersburg State University

On 2011-03-14 18:14, Anton Korobeynikov wrote: > Hello Xerxes, > >> llvm 2.9rc1 test on Dualcore ARM running Ubuntu Natty > What is the gcc used for the compilation? Can you try to do the -O0 > build and see whether this changed the stuff? > xranby at panda:/media/dh0/llvm-2.9-build-O0$ gcc --version gcc (Ubuntu/Linaro 4.5.2-5ubuntu1) 4.5.2 Copyright (C) 2010 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not ev...

...llvm-gcc (GCC) 4.0.1 (Apple Computer, Inc. build 5449)(LLVM build ) llvm-gcc-bc: llvm-gcc (GCC) 4.0.1 (Apple Computer, Inc. build 5449)(LLVM build ) Benchmark runtime comp code data bss compiler options hello.cpp 0.01 1.20 1904 320 148 g++-4.1 -O0 hello.cpp 0.01 1.24 2365 328 148 g++-4.2 -O0 hello.cpp 0.01 1.36 353236 11103 23736 llvm-g++ -O0 hello.cpp 0.01 1.23 1499 300 148 llvm-g++-bc -O0 hello.cpp 0.01 1.27 2186 320 148 icc -O0 hello.c...

@Craig and @Michael After installing clang-5.0 (download from http://releases.llvm.org, does not have Flang build's slowdown mention above), 1. clang++ -O0 -Xclang -disable-O0-optnone -Xclang -disable-llvm-passes -c -emit-llvm -o a.bc LULESH.cc; opt -O3 a.bc -o b.bc; llc -O3 -filetype=obj b.bc -o b.o ; clang++ b.o -o b.out; ./b.out 20 runtime: 2.354069e+01 2. clang++ -O1 -Xclang -disable-O0-optnone -Xclang -disable-llvm-passes -c -emit-llvm -o a.bc L...

...hub.com/flang-compiler/flang/issues/356 I have no idea about the root cause. Maybe due to debug symbols. But, I already use -DCMAKE_BUILD_TYPE=Release. Anyway, I believe there is a bug somewhere. On Sat, Jan 6, 2018 at 3:43 PM, Craig Topper <craig.topper at gmail.com> wrote: > -disable-O0-optnone has no effect with anything other than -O0. > > -O0 being passed to clang also causes all functions to be marked noinline. > I don't know if there is a command line option to turn that off. > > I recommend passing "-O1 -Xclang -disable-llvm-passes" to clang. Pas...

-disable-O0-optnone has no effect with anything other than -O0. -O0 being passed to clang also causes all functions to be marked noinline. I don't know if there is a command line option to turn that off. I recommend passing "-O1 -Xclang -disable-llvm-passes" to clang. Passing -O0 very specifica...

...> I have no idea about the root cause. > Maybe due to debug symbols. But, I already use -DCMAKE_BUILD_TYPE=Release. > Anyway, I believe there is a bug somewhere. > > > On Sat, Jan 6, 2018 at 3:43 PM, Craig Topper <craig.topper at gmail.com> > wrote: > >> -disable-O0-optnone has no effect with anything other than -O0. >> >> -O0 being passed to clang also causes all functions to be marked >> noinline. I don't know if there is a command line option to turn that off. >> >> I recommend passing "-O1 -Xclang -disable-llvm-passes...

...offset = 24, value = 64 MemoryAccess to pointer: float* inttoptr (i64 47246749696 to float*) { Stmt__12_cloned_[i0, i1, i2] -> MemRef_nttoptr (i64 47246749696 to float*)[4096i0 + 64i1 + i2] } allocSize: 4 storeSize: 4 replacedBy: { Stmt__12_cloned_[i0, i1, i2] -> NULL[o0] : o0 >= 47246749696 + 16384i0 + 256i1 + 4i2 and o0 <= 47246749699 + 16384i0 + 256i1 + 4i2 } MemoryAccess to pointer: float* inttoptr (i64 47247802368 to float*) { Stmt__12_cloned_[i0, i1, i2] -> MemRef_nttoptr (i64 47247802368 to float*)[4096i0 + 64i1 + i2] } allocSize: 4 stor...

Hi everyone, I found that Clang -O0 performs optimizations that undermine dynamic bug-finding tools. First, most bug finding tools such as ASan, Valgrind, Dr. Memory, Mudflap, Purify and Safe Sulong (on which I am working) rely on detecting errors during the execution of the program. They either insert additional checks during compi...

In D28404, Mehdi wanted to use the 'optnone' attribute as a way to record "I was compiled with -O0" in the IR, because it seems like a good idea to remember that fact in an LTO compilation and there is no way to remember that fact currently. A couple of people felt it might be better to have this idea discussed on the dev list, where it might get better exposure, so I'm volunteering to...

On Mar 15, 2011, at 4:45 AM, Xerxes Rånby wrote: > On 2011-03-14 18:14, Anton Korobeynikov wrote: >> Hello Xerxes, >> >>> llvm 2.9rc1 test on Dualcore ARM running Ubuntu Natty >> What is the gcc used for the compilation? Can you try to do the -O0 >> build and see whether this changed the stuff? >> > > xranby at panda:/media/dh0/llvm-2.9-build-O0$ gcc --version > gcc (Ubuntu/Linaro 4.5.2-5ubuntu1) 4.5.2 > Copyright (C) 2010 Free Software Foundation, Inc. > This is free software; see the source for copying conditi...

The driving goal of 'optnone' is to have an easy way for programmers to get an "-O0 like" debugging experience for selected functions, without making them build everything with –O0. To that end, we turn off as much optimization as we reasonably can, but in the context of a pipeline that is generally expecting optimizations to be enabled, in practice we can't exactly match...

On 01/01/2013 02:45 PM, Duncan Sands wrote: > Hi Dmitry, > >> >> In our compiler we use a modified version LLVM Polly, which is very >> sensitive to >> proper code generation. Among the number of limitations, the loop region >> (enclosed by phi node on induction variable and branch) is required to >> be free >> of additional memory-dependent

Hello, I encounter a bug that pumped during execution of "clang -O1". However the bug cannot be reproduced by using "clang -O0 + opt -O1". It seems that "clang -O1" is not the same as "clang -O0 + opt -O1". According to the generated LLVM IRs are large, I would like to use bugpoint with "clang -O1" directly instead of using "clang -O0" first and using bugpoint with "opt -O1...

I don't think "clang -help" prints options about optimizations. Clang itself doesn't have direct support for fine grained optimization control. Just the flag for levels -O0/-O1/-O2/-O3. This is intended to be simple and sufficient interface for most users who just want to compile their code. So I don't think there's a way to pass just -dse to clang. opt on the other hand is more of a utility for developers of llvm that provides fine grained control of optimiz...

...y 24, 2017, at 6:00 AM, Kristof Beyls <kristof.beyls at arm.com> wrote: > >> >> On 23 May 2017, at 21:48, Quentin Colombet <qcolombet at apple.com <mailto:qcolombet at apple.com>> wrote: >> >> Great! >> I thought I had to look at our pipeline at O0 to make sure optimized regalloc was supported (https://bugs.llvm.org/show_bug.cgi?id=33022 <https://bugs.llvm.org/show_bug.cgi?id=33022> in mind). Glad I was wrong, it saves me some time. >> >>> On May 22, 2017, at 12:51 AM, Kristof Beyls <kristof.beyls at arm.com <mailt...

...> * A lot of the biggest regressions are caused by unnecessarily moving > floating point values through general purpose registers. I've raised > http://bugs.llvm.org/show_bug.cgi?id=32550 for this. I think this one > definitely needs fixing before enabling GlobalISel by default at -O0. > * FastISel seems to transform division-by-constant-power-of-2 into right > shift (see > https://github.com/llvm-mirror/llvm/blob/master/lib/CodeGen/SelectionDAG/FastISel.cpp#L456-L468). > GlobalISel does not. It seems to me that at -O0 there may be reasons not > perform this trans...

Well, 'optnone' is already not identical to -O0, and given the nature of things, probably can't be; but I am persuaded that it's reasonable for it to honor the -fast-isel option as a debugging tactic. I'll take an AI to make this happen. Thanks, --paulr P.S. One nit, the "O0 + optnone" case should not have an asterisk, the...

...lution. On Fri, Jan 5, 2018 at 10:00 PM, Craig Topper <craig.topper at gmail.com> wrote: > I don't think "clang -help" prints options about optimizations. Clang > itself doesn't have direct support for fine grained optimization control. > Just the flag for levels -O0/-O1/-O2/-O3. This is intended to be simple and > sufficient interface for most users who just want to compile their code. So > I don't think there's a way to pass just -dse to clang. > > opt on the other hand is more of a utility for developers of llvm that > provides fine gr...