Hi there, Is this one ok to trunk?
BR, Terry On Wed, Apr 15, 2015 at 6:45 PM, Hale Wang <hale.w...@arm.com> wrote: > Ping for trunk? > > Hale > >> -----Original Message----- >> From: Richard Sandiford [mailto:rdsandif...@googlemail.com] >> Sent: Friday, February 27, 2015 4:04 AM >> To: Terry Guo >> Cc: Segher Boessenkool; Richard Sandiford; GCC Patches; Hale Wang >> Subject: Re: Ping : [PATCH] [gcc, combine] PR46164: Don't combine the > insns >> if a volatile register is contained. >> >> Terry Guo <flame...@gmail.com> writes: >> > On Thu, Feb 26, 2015 at 1:55 PM, Segher Boessenkool >> > <seg...@kernel.crashing.org> wrote: >> >> On Tue, Feb 17, 2015 at 11:39:34AM +0800, Terry Guo wrote: >> >>> On Sun, Feb 15, 2015 at 7:35 PM, Segher Boessenkool >> >>> <seg...@kernel.crashing.org> wrote: >> >>> > Hi Terry, >> >>> > >> >>> > I still think this is stage1 material. >> >>> > >> >>> >> + /* Don't combine if dest contains a user specified register and >> >>> >> i3 contains >> >>> >> + ASM_OPERANDS, because the user specified register (same with >> >>> >> dest) in i3 >> >>> >> + would be replaced by the src of insn which might be different >> with >> >>> >> + the user's expectation. */ >> >>> > >> >>> > "Do not eliminate a register asm in an asm input" or similar? >> >>> > Text explaining why REG_USERVAR_P && HARD_REGISTER_P works >> here >> >>> > would be good to have, too. >> >> >> >>> diff --git a/gcc/combine.c b/gcc/combine.c index f779117..aeb2854 >> >>> 100644 >> >>> --- a/gcc/combine.c >> >>> +++ b/gcc/combine.c >> >>> @@ -1779,7 +1779,7 @@ can_combine_p (rtx_insn *insn, rtx_insn *i3, >> >>> rtx_insn *pred ATTRIBUTE_UNUSED, { >> >>> int i; >> >>> const_rtx set = 0; >> >>> - rtx src, dest; >> >>> + rtx src, dest, asm_op; >> >>> rtx_insn *p; >> >>> #ifdef AUTO_INC_DEC >> >>> rtx link; >> >>> @@ -1914,6 +1914,14 @@ can_combine_p (rtx_insn *insn, rtx_insn *i3, >> rtx_insn *pred ATTRIBUTE_UNUSED, >> >>> set = expand_field_assignment (set); >> >>> src = SET_SRC (set), dest = SET_DEST (set); >> >>> >> >>> + /* Use REG_USERVAR_P and HARD_REGISTER_P to check whether >> DEST is a user >> >>> + specified register, and do not eliminate such register if it is > in an >> >>> + asm input because we may end up with something different with >> user's >> >>> + expectation. */ >> >> >> >> That doesn't explain why this will hit (almost) only on register asms. >> >> The user's expectation doesn't matter that much either: GCC would >> >> violate its own documentation / promises, that matters more ;-) >> >> >> >>> + if (REG_P (dest) && REG_USERVAR_P (dest) && HARD_REGISTER_P >> (dest) >> >>> + && ((asm_op = extract_asm_operands (PATTERN (i3))) != NULL)) >> >> >> >> You do not need the temporary variable, nor the != 0 or the extra >> >> parens; just write >> >> >> >> && extract_asm_operands (PATTERN (i3)) >> >> >> >> Cheers, >> >> >> >> >> >> Segher >> > >> > Thanks for comments. Patch is updated now. Please review again. >> >> Looks good to me FWIW. >> >> Thanks, >> Richard > > >
