On Fri, Aug 7, 2009 at 1:50 PM, pms<pmsh...@gmail.com> wrote:
>
> Hi,
> We've a problem here. we were trying to use cc1 with & without -O
> option to verify the optimizations happening in our sample code. these r the
> list of outputs after each compilation
> without -O
> p...@shiva:~/Desktop/Compilers/GCC/build/test$ ls
> 1.c 1.c.011t.ehopt 1.c.038t.release_ssa
> 1.c.001t.tu 1.c.012t.eh 1.c.123t.optimized
> 1.c.003t.original 1.c.013t.cfg 1.c.125t.blocks
> 1.c.004t.gimple 1.c.014t.cplxlower0 1.c.126t.final_cleanup
> 1.c.006t.vcg 1.c.015t.veclower 1.c.203t.statistics
> 1.c.007t.useless 1.c.021t.cleanup_cfg 1.s
> 1.c.010t.lower 1.c.023t.ssa a.out
>
> with -O
>
> 1.c 1.c.051t.ccp2 1.c.085t.sink
> 1.c.001t.tu 1.c.052t.forwprop2 1.c.086t.loop
> 1.c.003t.original 1.c.054t.alias 1.c.087t.loopinit
> 1.c.004t.gimple 1.c.055t.retslot 1.c.088t.copyprop4
> 1.c.006t.vcg 1.c.056t.phiprop 1.c.089t.dceloop1
> 1.c.007t.useless 1.c.057t.fre 1.c.090t.lim
> 1.c.010t.lower 1.c.058t.copyprop2 1.c.093t.sccp
> 1.c.011t.ehopt 1.c.059t.mergephi2 1.c.094t.empty
> 1.c.012t.eh 1.c.061t.dce1 1.c.099t.ivcanon
> 1.c.013t.cfg 1.c.062t.cselim 1.c.104t.cunroll
> 1.c.015t.veclower 1.c.063t.ifcombine 1.c.107t.ivopts
> 1.c.021t.cleanup_cfg 1.c.064t.phiopt1 1.c.108t.loopdone
> 1.c.023t.ssa 1.c.066t.ch 1.c.111t.reassoc2
> 1.c.024t.early_optimizations 1.c.068t.cplxlower 1.c.113t.dom2
> 1.c.025t.einline2 1.c.069t.sra 1.c.114t.phicprop2
> 1.c.026t.copyrename1 1.c.070t.copyrename3 1.c.115t.cddce2
> 1.c.027t.ccp1 1.c.071t.dom1 1.c.117t.dse2
> 1.c.028t.forwprop1 1.c.072t.phicprop1 1.c.118t.forwprop4
> 1.c.029t.addressables1 1.c.073t.dse1 1.c.119t.phiopt3
> 1.c.030t.esra 1.c.074t.reassoc1 1.c.121t.copyrename4
> 1.c.031t.copyprop1 1.c.075t.dce2 1.c.122t.uncprop
> 1.c.032t.mergephi1 1.c.076t.forwprop3 1.c.123t.optimized
> 1.c.033t.cddce1 1.c.077t.phiopt2 1.c.124t.nrv
> 1.c.034t.sdse 1.c.078t.objsz 1.c.125t.blocks
> 1.c.036t.switchconv 1.c.079t.ccp3 1.c.126t.final_cleanup
> 1.c.037t.profile 1.c.080t.copyprop3 1.c.203t.statistics
> 1.c.038t.release_ssa 1.c.081t.fab 1.s
> 1.c.048t.addressables2 1.c.082t.sincos a.out
> 1.c.049t.copyrename2 1.c.083t.crited
>
> But here, we tried to see the differences, until 1.c.027t.ccp1, the output
> for the following source 1.c
> #include
> int main()
>
> {
> int a=5;
> int b;
> b=a;
> printf("the number is :%d",b);
> }
>
> was 1.c.026t.copyrename1
> ;; Function main (main)
>
> main ()
> {
> int b;
> int a;
>
> :
> a_2 = b_1(D);
> return;
>
> }
> but in 1.c.027t.ccp1, the output doesnot contain the actual assignment b=a.
> ;; Function main (main)
>
> main ()
> {
> int b;
> int a;
>
> :
> return;
>
> }
>
> We want to know, without b=a, how is it generating the final code for b=a
Nothing. Because it's a dead statement.
Richard.
> Kindly help
>
> --
> View this message in context:
> http://www.nabble.com/regarding-optimization-options-in-phase-ordering-tp24863416p24863416.html
> Sent from the gcc - Dev mailing list archive at Nabble.com.
>
>
