similar to: [LLVMdev] interesting optimization

Hello, guys. I am trying to construct higher-level 'for' from the low-level LLVM bitcode(ver 1.9). It's partly successful thanks to David A. Greene's advice suggested to use Control Dependence Graph(CDG). I could find which BB contributes to form which loop with CDG. For example, for this simple function: ----------------------------------------------------------- void bsloop(int

Hi, I'm trying to write up my little m68k backend things have been going smoothly. I've been working with the x86 backend as a template, fixing things as I go. Now I've run into branches and I have a crash I don't really understand. Here's the sample IR I'm running llc on to generate assembly: define i32 @ilog2(i32 %x) { entry: %tmp718 = icmp eq i32 %x, 0

Hi, Seems pass scalar-evolution+indvars fail to get the loop trip count of the following case: int foo(int x, int y, int lam[256], int alp[256]) { int i; int z = y; for (i = 255; i >= 0; i--) { z += x; lam[i] = alp[i]; } return z; } The final optimized ll code is : define i32 @foo(i32 %x, i32 %y, i32* %lam, i32* %alp) nounwind { entry: br label %bb bb:

On 08/15/2013 03:32 AM, Star Tan wrote: > Hi all, Hi, I tried to reproduce your findings, but could not do so. > I have investigated the 6X extra compile-time overhead when Polly compiles the simple nestedloop benchmark in LLVM-testsuite. (http://188.40.87.11:8000/db_default/v4/nts/31?compare_to=28&baseline=28). Preliminary results show that such compile-time overhead is resulted by

The following C code : #include <stdio.h> #include <stdlib.h> int TESTE2( int parami , int paraml ,double paramd ) { int varx=0,vary; int nI =0; //varx= parami; if( parami > 0 ) { varx = parami; vary = varx + 1; } else { varx = vary + 1; vary = paraml; } varx = varx + parami + paraml; for( nI = 1 ; nI <= paraml; nI++) { varx =

yes, this is valid assuming bb9 dominates bb10. Not sure what you mean by "support this", unless your tool doesn't handle certain types of CFG's On Wed, Mar 30, 2016 at 8:12 PM, Xiaochu Liu via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Dear there, > > Is the following phi instruction valid? > > %j_8 = phi i32 [ %j_100, %"<bb 13>" ], [

I would like to be able to instrument va_arg, but when I generate a bc file for a test case using: llvm-gcc -O3 -emit-llvm vararg.c -c -o vararg.bc I do not see va_arg. Instead, it seems the args are accessed through %struct.__va_list_tag, which makes things a bit trickier to instrument. Is there a way to force llvm-gcc to use va_arg? Perhaps there is some documentation about va_list_tag or

​Hi, Would you be able to kindly check and assist with the IndVarSimplify / SCEV problem I got in the latest LLVM, please? Sometimes IndVarSimplify may not eliminate narrow IV's when there actually exists such a possibility. This may affect other LLVM passes and result in inefficient code. The reproducing test 'indvar_test.cpp' is attached. The problem is with the second

instcombine doesn't seem to be doing it. From my testing it seems to only occur when I use -indvars after a long string of commands. For example: llvm-as < test_fc_27.ll | opt -preverify -domtree -verify -lowersetjmp -raiseallocs -simplifycfg -domtree -domfrontier -mem2reg -globalopt -globaldce -ipconstprop -deadargelim -instcombine -simplifycfg -ba siccg -prune-eh -inline

The following C test program was compiled using LLVM with -O3 option and MSVC with /O2. The MSVC one is about 600 times faster than the one compiled with the LLVM. We can see that the for loop in MSVC assembler is solved in the optimization pass more efficiently than that in LLVM. Is there an way to get a optimization result in LLVM like that of the MSVC? Manoel Teixeira #include

Hello . I ran opt with -indvars options , got wrong result.  This is my example: test.cc :  int test(int a)                 {      for (int i = 2; i < a; ++i) {                            a += ;      }              return a; } clang -O3 -emit-llvm -S test.cc -o test.ll opt -indvards -S test.ll  -o indvars.ll > /dev/null indvars.ll : ; ModuleID = 'test.ll' target datalayout =

I was trying the new feature you introduce about printing out the graphs, so I updated my version of llvm/clang/polly synchronizing them to the last version, but I get this error launching clang (also , I recently switched to MacOS X for development): $ clang not_so_simple_loop.c -O3 -Xclang -load -Xclang ${PATH_TO_POLLY_LIB}/LLVMPolly.dylib -mllvm -enable-polly-viewer -mllvm -enable-iv-rewrite

Hi all, I would like to know which optimization passes are performed at -O2 by opt. So I used following command: llvm-as < /dev/null | opt -O2 -std-compile-opts -disable-output -debug-pass=Arguments I've got following output for LLVM opt 2.9: Pass Arguments: -no-aa -tbaa -basicaa -simplifycfg -domtree -scalarrepl -early-cse Pass Arguments: -targetlibinfo -no-aa -tbaa -basicaa

On 07/27/2011 03:11 PM, Jimborean Alexandra wrote: > Hello, > > How can I compute the functions on the loop iterators used as array > indices? > > For example: > > for i = 0, N > for j = 0, M > A[2*i + j - 10] = ... > > Can I obtain that this instruction A[2*i + j - 10]= .. always accesses > memory using a function f(i,j) = 2*i + j - 10 + base_address_of_A

Hi I have this program in which fooBuf can only take on NULL or the address of local_fooBuf, and fooBuf and local_fooBuf have scope of the foo function. Therefore there is no way for the fooPtr argument to alias with fooBuf. However, LLVM basicaa and globalsmodref-aa say the 2 pointers may alias. I am thinking whether i should implement a limited form of point-to alias on the fooBuf pointer in

On 10/07/2011 03:43 PM, Marcello Maggioni wrote: > 2011/10/7 Marcello Maggioni<hayarms at gmail.com>: >> Hi, >> >> for example this loop: >> >> #include<stdio.h> >> >> int main() >> { >> int A[1024]; >> int j, k=10; >> for (j = 1; j< 1024; j++) >> A[j] =

On 10/22/2011 08:41 AM, Marcello Maggioni wrote: > I was trying the new feature you introduce about printing out the > graphs, so I updated my version of llvm/clang/polly synchronizing them > to the last version, but I get this error launching clang (also , I > recently switched to MacOS X for development): > > $ clang not_so_simple_loop.c -O3 -Xclang -load -Xclang >

Hi all, I have investigated the 6X extra compile-time overhead when Polly compiles the simple nestedloop benchmark in LLVM-testsuite. (http://188.40.87.11:8000/db_default/v4/nts/31?compare_to=28&baseline=28). Preliminary results show that such compile-time overhead is resulted by the complicated polly-dependence analysis. However, the key seems to be the polly-prepare pass, which introduces

Strange , with --enable-shared (I use auto tool by the way ...) it gives: MacBook-Pro-di-Marcello:examples Kariddi$ ./compile_ex.sh not_so_simple_loop clang (LLVM option parsing): Unknown command line argument '-enable-polly-viewer'. Try: 'clang (LLVM option parsing) -help' clang (LLVM option parsing): Did you mean '-enable-polly-vector'? Seems like it doesn't

Hi, I found issues with INDVARS <-> LSR passes interactions after https://reviews.llvm.org/rL346397. There were two main changes in this commit: 1. Previously we were propagating SCEV add expressions even if DefInst of exit value has hard uses inside the loop. After rL346397 we forbid propagation of SCEV add expressions if DefInst of exit value has hard use inside the loop. 2. Previously