[PATCH] Improve adc discovery during combine on x86 (PR target/85095, take 2)

On Wed, Mar 28, 2018 at 08:51:07AM +0200, Uros Bizjak wrote: > > --- gcc/config/i386/i386.md.jj 2018-03-27 12:54:54.685244368 +0200 > > +++ gcc/config/i386/i386.md 2018-03-27 19:38:43.891451026 +0200 > > @@ -6854,6 +6854,23 @@ (define_insn "add3_carry" > > (set_attr "pent_pair" "pu") > >

Re: [PATCH] Improve adc discovery during combine on x86 (PR target/85095, take 2)

On Wed, Mar 28, 2018 at 2:54 PM, Jakub Jelinek wrote: > On Wed, Mar 28, 2018 at 08:51:07AM +0200, Uros Bizjak wrote: >> > --- gcc/config/i386/i386.md.jj 2018-03-27 12:54:54.685244368 +0200 >> > +++ gcc/config/i386/i386.md 2018-03-27 19:38:43.891451026 +0200 >> > @@ -6854,6 +6854,23 @@ (define

Re: [PATCH] Improve adc discovery during combine on x86 (PR target/85095)

On Tue, Mar 27, 2018 at 11:11 PM, Jakub Jelinek wrote: > Hi! > > In 6.x we've changed unsigned if (a < b) a++; into ADD_OVERFLOW ifn, > which results in different expanded code, which on the following testcase > unfortunately doesn't combine anymore into the optimal 3 instructions. > > The problem

[PATCH] Improve adc discovery during combine on x86 (PR target/85095)

Hi! In 6.x we've changed unsigned if (a < b) a++; into ADD_OVERFLOW ifn, which results in different expanded code, which on the following testcase unfortunately doesn't combine anymore into the optimal 3 instructions. The problem is that we want adc[lq] $0, %reg instruction, but simplify-rtx.c le