> -----Original Message----- > From: Ramana Radhakrishnan [mailto:ramana....@googlemail.com] > Sent: Saturday, November 24, 2012 7:20 AM > To: Bin Cheng > Cc: gcc-patches@gcc.gnu.org; Ramana Radhakrishnan; Richard Earnshaw; Richard > Sandiford > Subject: Re: [PING Updated]: [PATCH GCC/ARM] Fix problem that hardreg_cprop > opportunities are missed on thumb1 > > Ok if no regressions. > I re-tested it against trunk and committed it as r193841
Thanks. > Ramana > > On Wed, Oct 10, 2012 at 9:57 AM, Bin Cheng <bin.ch...@arm.com> wrote: > > Ping^2 > > > >> -----Original Message----- > >> From: gcc-patches-ow...@gcc.gnu.org > >> [mailto:gcc-patches-ow...@gcc.gnu.org] > > On > >> Behalf Of Bin Cheng > >> Sent: Monday, October 08, 2012 2:36 PM > >> To: gcc-patches@gcc.gnu.org > >> Cc: Ramana Radhakrishnan; Richard Earnshaw; 'Richard Sandiford' > >> Subject: RE: [PING Updated]: [PATCH GCC/ARM] Fix problem that > > hardreg_cprop > >> opportunities are missed on thumb1 > >> > >> Ping. > >> > >> > -----Original Message----- > >> > From: gcc-patches-ow...@gcc.gnu.org > >> > [mailto:gcc-patches-ow...@gcc.gnu.org] > >> On > >> > Behalf Of Bin Cheng > >> > Sent: Tuesday, September 25, 2012 4:00 PM > >> > To: 'Richard Sandiford' > >> > Cc: Ramana Radhakrishnan; Richard Earnshaw; gcc-patches@gcc.gnu.org > >> > Subject: RE: [Updated]: [PATCH GCC/ARM] Fix problem that > >> > hardreg_cprop opportunities are missed on thumb1 > >> > > >> > > >> > > -----Original Message----- > >> > > From: Richard Sandiford [mailto:rdsandif...@googlemail.com] > >> > > Sent: Wednesday, September 05, 2012 6:09 AM > >> > > To: Bin Cheng > >> > > Cc: Ramana Radhakrishnan; 'Eric Botcazou'; > >> > > gcc-patches@gcc.gnu.org > >> > > Subject: Re: Ping: [PATCH GCC/ARM] Fix problem that hardreg_cprop > >> > > opportunities are missed on thumb1 > >> > > >> > > Subtraction of zero isn't canonical rtl though. Passes after > >> > > peephole2 > >> > would > >> > > be well within their rights to simplify the expression back to a move. > >> > > From that point of view, making the passes recognise (plus X 0) > >> > > and (minus > >> > X 0) > >> > > as special cases would be inconsistent. > >> > > > >> > > Rather than make the Thumb 1 CC usage implicit in the rtl stream, > >> > > and > >> > carry > >> > > the current state around in cfun->machine, it seems like it would > >> > > be > >> > better to > >> > > get md_reorg to rewrite the instructions into a form that makes > >> > > the use of condition codes explicit. > >> > > > >> > > md_reorg also sounds like a better place in the pipeline than > >> > > peephole2 to > >> > be > >> > > doing this kind of transformation, although I admit I have zero > >> > > evidence > >> > to > >> > > back that up... > >> > > > >> > > >> > Hi Richard, > >> > > >> > This is the updated patch according to your suggestions. I removed > >> > the > >> > peephole2 patterns and introduced function thumb1_reorg to rewrite > >> > instructions in md_reorg pass. > >> > > >> > In addition to missed propagation, this patch also detects > >> > following > > case: > >> > mov r5, r0 > >> > str r0, [r4] <-------miscellaneous irrelevant instructions > >> > [cmp r0, 0] <-------saved > >> > bne .Lxxx > >> > > >> > Patch tested on arm-none-eabi/cortex-m0, no regressions introduced. > >> > > >> > Is it OK? > >> > > >> > Thanks. > >> > > >> > 2012-09-25 Bin Cheng <bin.ch...@arm.com> > >> > > >> > * config/arm/arm.c (thumb1_reorg): New function. > >> > (arm_reorg): Call thumb1_reorg. > >> > (thumb1_final_prescan_insn): Record src operand in thumb1_cc_op0. > >> > * config/arm/arm.md : Remove peephole2 patterns which rewrites move > >> > into subtract of ZERO. > >> > >> > >>
