Re: Question on register renaming in rtl loop unroll pass

On Fri, Jun 28, 2013 at 6:39 PM, Eric Botcazou wrote: >> The problem is auto-inc-dec is weak and can only capture >> post-increment in first part of code, generating even worse code for >> RA: >> .L1: >> r197 <- r162 >> [r197++] <- x >> ... >> [r162+4] <- y >> r162 <- r197+0x4 >> ... >

Re: Question on register renaming in rtl loop unroll pass

> The problem is auto-inc-dec is weak and can only capture > post-increment in first part of code, generating even worse code for > RA: > .L1: > r197 <- r162 > [r197++] <- x > ... > [r162+4] <- y > r162 <- r197+0x4 > ... > b .L1 > Now we have two live registers and it seems hard to el

Re: Question on register renaming in rtl loop unroll pass

On Fri, Jun 28, 2013 at 6:10 PM, Eric Botcazou wrote: >> Hi, I have a question about register renaming in rtl loop unroll. >> For an example loop: >> .L1: >> [r162] <- x >> r162 <- r162 + 4 >> ... >> b .L1 >> >> After unrolling: >> .L1: >> [r162] <- x >> r197 <- r162 + 4 >> r162 <-

Re: Question on register renaming in rtl loop unroll pass

> Hi, I have a question about register renaming in rtl loop unroll. > For an example loop: > .L1: > [r162] <- x > r162 <- r162 + 4 > ... > b .L1 > > After unrolling: > .L1: > [r162] <- x > r197 <- r162 + 4 > r162 <- r197 > ... > [r162] <- y > r162 <- r197 + 4 > ... > b .L

Question on register renaming in rtl loop unroll pass

Hi, I have a question about register renaming in rtl loop unroll. For an example loop: .L1: [r162] <- x r162 <- r162 + 4 ... b .L1 After unrolling: .L1: [r162] <- x r197 <- r162 + 4 r162 <- r197 ... [r162] <- y r162 <- r197 + 4 ... b .L1 Why not: .L1: [r162] <- x r16