This is the mail archive of the
`gcc-patches@gcc.gnu.org`
mailing list for the GCC project.

Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|

Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |

Other format: | [Raw text] |

*From*: Richard Biener <richard dot guenther at gmail dot com>*To*: Igor Zamyatin <izamyatin at gmail dot com>*Cc*: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Yuri Rumyantsev <ysrumyan at gmail dot com>*Date*: Tue, 9 Apr 2013 10:18:58 +0200*Subject*: Re: FW: [PATCH] Avoid a few find_base_term calls in alias.c*References*: <CAKdSQZn7bEq4AWdfOFHexXjKh_qTjALWvCZ7g_=2umK1kNz5FA at mail dot gmail dot com>

On Tue, Apr 9, 2013 at 9:42 AM, Igor Zamyatin <izamyatin@gmail.com> wrote: > Richard, > > Any plans to commit your new fix? I did already. Richard. > > Thanks, > Igor > >> On Thu, Apr 4, 2013 at 3:33 PM, Yuri Rumyantsev <ysrumyan@gmail.com> >> wrote: >> > Hi Richard, >> > >> > You slightly change behavior of find_base_term, namely before your fix >> > we have the following code: >> > >> > if (REG_P (tmp1) && REG_POINTER (tmp1)) { >> > rtx base = find_base_term (tmp1); >> > if (base) >> > return base; >> > } >> > >> > but in your fix you added the following checks on base: >> > >> > tmp1 = find_base_term (tmp1); >> > if (tmp1 != NULL_RTX >> > && ((REG_P (tmp1) && REG_POINTER (tmp1)) >> > || known_base_value_p (tmp1))) >> > return tmp1; >> > Why you added these checks since function arguments may not considered >> > as bases. >> >> If you continue down the original function there is (quoted fully) >> >> /* If either operand is known to be a pointer, then use it >> to determine the base term. */ >> if (REG_P (tmp1) && REG_POINTER (tmp1)) >> { >> rtx base = find_base_term (tmp1); >> if (base) >> return base; >> } >> >> if (REG_P (tmp2) && REG_POINTER (tmp2)) >> { >> rtx base = find_base_term (tmp2); >> if (base) >> return base; >> } >> >> /* Neither operand was known to be a pointer. Go ahead and find >> the >> base term for both operands. */ >> tmp1 = find_base_term (tmp1); >> tmp2 = find_base_term (tmp2); >> >> so we call find_base_term on tmp1 anyway, and after the modification >> >> tmp1 = find_base_term (tmp1); >> if (tmp1 != NULL_RTX >> && ((REG_P (tmp1) && REG_POINTER (tmp1)) >> || known_base_value_p (tmp1))) >> return tmp1; >> >> we take it if it is non-NULL and ... ah, I see. We now check >> REG_P/REG_POINTER on the new value. That was indeed unintended. >> >> I'll fix it like below. >> >> Richard. >> >> 2013-04-04 Richard Biener <rguenther@suse.de> >> >> * alias.c (find_base_term): Fix thinko in previous change. >> >> Index: gcc/alias.c >> =================================================================== >> --- gcc/alias.c (revision 197480) >> +++ gcc/alias.c (working copy) >> @@ -1687,16 +1687,16 @@ find_base_term (rtx x) >> term is from a pointer or is a named object or a special >> address >> (like an argument or stack reference), then use it for the >> base term. */ >> - tmp1 = find_base_term (tmp1); >> - if (tmp1 != NULL_RTX >> + rtx base = find_base_term (tmp1); >> + if (base != NULL_RTX >> && ((REG_P (tmp1) && REG_POINTER (tmp1)) >> - || known_base_value_p (tmp1))) >> - return tmp1; >> - tmp2 = find_base_term (tmp2); >> - if (tmp2 != NULL_RTX >> + || known_base_value_p (base))) >> + return base; >> + base = find_base_term (tmp2); >> + if (base != NULL_RTX >> && ((REG_P (tmp2) && REG_POINTER (tmp2)) >> - || known_base_value_p (tmp2))) >> - return tmp2; >> + || known_base_value_p (base))) >> + return base; >> >> /* We could not determine which of the two operands was the >> base register and which was the index. So we can determine > >

Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|

Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |