similar to: tool options to generate spill code

Hello, I have studied register allocation in theoretical aspects and exploring the same in the implementation level. I need a minimal testcase for register spilling to analyze spilling procedure in llvm. I tried with a testcase taking 20 variables but all the 20 variables are getting stored in the stack using %rbp. Maybe my live variable analysis is wrong. Please help me with a minimal testcase

Let in a program a variable 'x' is tainted. There is an assignment 'y=x' where y is untainted. How to check the taintflow in the output or data flow graph ? Any suggestions? Thank you. Have a great day. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20190912/5bb3655c/attachment.html>

hello, I am trying to build LLVM with default options. I am getting the following error message after make. [100%] Building C object tools/llvm-c-test/CMakeFiles/llvm-c-test.dir/metadata.c.o [100%] Building C object tools/llvm-c-test/CMakeFiles/llvm-c-test.dir/module.c.o [100%] Building C object tools/llvm-c-test/CMakeFiles/llvm-c-test.dir/object.c.o [100%] Building C object

Hello, I have a few general questions. 1. Whether the memory contents assigned for a function are accessible after we return from that function? If yes, how can we access it? 2. Does llvm delete the stackframe assigned for a specific function, after we return from that function? 3. If not, how can we delete the stackframe or clear the memory content after we return from the function? Where do

Hello, I just upgraded my llvm to 5.0.0. I applied mem2reg pass as follows: opt -mem2reg m2rtttl.bc > m2rtttl.opt But after that, I compared m2rtttl.bc and m2rtttl.opt. I noticed that there are no difference between m2rtttl.bc and m2rtttl.opt. Did I apply llvm in the correct way? Thanks a lot for the help! Best, Linhai -------------- next part

On Wed, Jun 21, 2017 at 05:25:04PM -0700, Mehdi AMINI via llvm-dev wrote: > Hi Kuba, > > Try: > > __attribute__(optnone) > > See > https://clang.llvm.org/docs/AttributeReference.html#optnone-clang-optnone Actually, it should be enough to use: __attribute__((noinline)) void please_do_not_optimize_me_away(int arg1, void *arg2) { asm

Hi llvm-dev, I have a C function: __attribute__((__visibility__("default"))) __attribute__((used)) __attribute__((noinline)) void please_do_not_optimize_me_away(int arg1, void *arg2) { asm volatile("" :::); } (the purpose is that this function will be used dynamically at runtime, perhaps by interposing the function, or via the debugger) I really thought this will not get

Hi all, I am trying to understand the effectiveness of various llvm optimisations when a language targets llvm (or C) as its backend. The following is my approach (please correct me if I did anything wrong): I am trying to explicitly control the optimisations passes in llvm. I disable optimisation in clang, but instead emit unoptimized llvm IR, and use opt to optimise that. These are what I

Have -O0 on your clang command line causes all functions to get marked with an 'optnone' attribute that prevents opt from being able to optimize them later. You should also add "-Xclang -disable-O0-optnone" to your command line. ~Craig On Thu, Sep 21, 2017 at 10:04 PM, Yi Lin via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Hi all, > > I am trying to

Various options for reducing memory usage when building LLVM: * Don't use bfd-ld, at least use gold, probably use lld if you have it available * With Ninja and/or CMake there's some way to specify the maximum number of concurrent linkactions - lower this to fit in your available memory * If you're building with debug info: Use Split DWARF On Thu, Jan 2, 2020 at 5:21 AM Kókai Péter

Hi, all, I think I found a bug on mem2reg in a particular case. When I ran opt -mem2reg -basicaa -scalar-evolution -loops -da -analyze opts.ll, it collapsed. While without mem2reg option, it runs well. so I guess it has something to do with mem2reg. The relative files have been affixed, please check them for me. Thanks in advance. liubaosen at tsinghua.edu.cn -------------- next part

The last time this came up, we agreed something should be done to fix the defaults, but nobody picked it up and ran with it. I think there was consensus, it just needs legwork now. On Thu, Jan 2, 2020 at 11:58 AM Aaron Smith via llvm-dev < llvm-dev at lists.llvm.org> wrote: > There was a recent thread on reducing memory: >

Awesome, thanks! Now I have another question. I have a matrix multiplication code. This is my code: #include <stdio.h> #include <stdlib.h> #define n 4 int main(int argc, char *argv[]) { int i, j, k; int A[n][n], B[n][n], C[n][n]; for(i=0;i<n;i++){ for(j=0;j<n;j++){ A[i][j] = 1; B[i][j] = 2; C[i][j] = 0; } }

I noticed that there is a '-run-pass' argument for llc. I am wondering if I can do a similar approach with machine level optimisations/passes for llc. Are those passes optional (so I can turn them off)? And how can I get MIR format as llc expects with '-run-pass'? Thanks a lot. Cheers, Yi On 22/9/17 15:10, Craig Topper wrote: > Have -O0 on your clang command line causes

Hi Vedant, Thank you for your reply. I think I can make this debugify-each mode, but I guess this is reserved for your GSoC project ? However, if I understand correctly, we do not want to take the output of the first check-debugify (I mean the .ll file with potentially all the WARNINGs and ERRORs after the first pass) as input for the second debugify. What we need is to take the fresh output of

Thank You.. I used following command to generate .bc or .ll /Documents/clang+llvm-4.0.0-x86_64-linux-gnu-ubuntu-16.04/bin/clang -O0 -emit-llvm -S -o vec4.ll vecsum.c /Documents/clang+llvm-7.0.0-x86_64-linux-gnu-ubuntu-16.04/bin/clang -O0 -emit-llvm -S -o vec7.ll vecsum.c On Wed, Jan 16, 2019 at 6:49 AM Sanjoy Das <sanjoy at playingwithpointers.com> wrote: > It is hard to tell

Hi all, I have the following C code: #include<stdio.h> int main(int argc, char *argv[]) { printf("%s\n", argv[0]); return argc; } that generates the following IR for the main function: ; Function Attrs: noinline nounwind optnone uwtable define i32 @main(i32, i8**) #0 { %3 = alloca i32, align 4 %4 = alloca i32, align 4 %5 = alloca i8**, align 8 store i32 0, i32*

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

> On Mar 16, 2018, at 2:30 PM, Son Tuan VU <sontuan.vu119 at gmail.com> wrote: > > Hi Vedant, > > Thank you for your reply. I think I can make this debugify-each mode, but I guess this is reserved for your GSoC project ? No, there's no reserved work. If you'd like to work on this I encourage you to do so. There's plenty of other work slated for the GSoC project.

On 4/15/2018 11:44 AM, Mustakimur Khandaker via llvm-dev wrote: > Hi > I have this simple c code for which I would like to use for alias > analysis. > > #include <stdio.h> > #include <stdlib.h> > > static int (*fp) (void); > void ind_call (int (*compr)(void)){ >     fp = compr; >     fp(); > } > int hello(void){