On Fri, 2020-03-13 at 09:09 +0100, Christophe Lyon wrote: > Hi, > > > On Thu, 12 Mar 2020 at 23:12, Jeff Law via Gcc-patches > <gcc-patches@gcc.gnu.org> wrote: > > On Thu, 2020-03-12 at 13:23 -0500, Segher Boessenkool wrote: > > > On Thu, Mar 12, 2020 at 12:03:08PM -0600, Jeff Law wrote: > > > > On Sat, 2020-02-08 at 10:41 -0600, Segher Boessenkool wrote: > > > > > I don't think each stanza of code should use it's own "noop-ness", no. > > > > Richard's patch is actually better than mine in that regard as it > > > > handles > > > > mem > > > > and > > > > reg nop moves in an indentical way. I don't think refactoring the cse.c > > > > code > > > > is > > > > advisable now though -- but I do want to fix the multiply-reported ICE > > > > on > > > > ARM > > > > and > > > > Richard's cse changes are the cleanest way to do that that I can see. > > > > > > It looks pretty simple, yeah... All of CSE is hopelessly fragile, but > > > this patch does not make things worse. > > > > > > > > I don't know if this patch makes matters worse or not. It doesn't > > > > > seem > > > > > suitable for stage 4 though. And Richard said the cse.c part breaks > > > > > rs6000, if that is true, yes I do object ;-) > > > > The rs6000 port breakage is trivial to fix. In fact, I did so and ran > > > > it > > > > through > > > > my tester, which includes ppc64le and ppc64 a slew of *-elf targets x86 > > > > native > > > > and more. > > > > > > I don't see anything rs6000 below? Is it just this generic code? > > > > > > > @@ -5324,9 +5324,11 @@ cse_insn (rtx_insn *insn) > > > > } > > > > > > > > /* Similarly, lots of targets don't allow no-op > > > > - (set (mem x) (mem x)) moves. */ > > > > + (set (mem x) (mem x)) moves. Even (set (reg x) (reg x)) > > > > + might be impossible for certain registers (like CC > > > > registers). */ > > > > else if (n_sets == 1 > > > > - && MEM_P (trial) > > > > + && ! CALL_P (insn) > > > > + && (MEM_P (trial) || REG_P (trial)) > > > > && MEM_P (dest) > > > > && rtx_equal_p (trial, dest) > > > > && !side_effects_p (dest) > > > > > > This adds the !CALL_P (no space btw) condition, why is that? > > > > > > (Is that CCmode reg-reg move comment about rs6000? Huh, we *do* have > > > patterns for that, or *should* have at least!) > > I fixed the extraneous whitespace and committed the change. > > > > The new test fails on ARM: THanks. I see what's happening, though I'm not sure *how* it happened. Anyway, doing some testing on the fix now.
jeff >
