Zdenek Dvorak - Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv (original) (raw)

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• From: Zdenek Dvorak
• To: Richard Guenther
• Cc: Christian BRUEL , Ian Lance Taylor , gcc-patches at gcc dot gnu dot org
• Date: Thu, 15 Feb 2007 17:00:28 +0100
• Subject: Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv
• References: <20070215093343.GA19299@atrey.karlin.mff.cuni.cz> <45D43AB6.4020709@st.com> <20070215111752.GA17650@atrey.karlin.mff.cuni.cz> <45D45681.1070902@st.com> <84fc9c000702150458r68b7d33bka3b4bf15dfc7c67f@mail.gmail.com> <20070215130453.GA1624@atrey.karlin.mff.cuni.cz> <84fc9c000702150644w246d3fcdv9486e60886e5ae64@mail.gmail.com> <20070215150023.GA16758@atrey.karlin.mff.cuni.cz> <84fc9c000702150732x79a77479m6d2a03738f8832e@mail.gmail.com> <84fc9c000702150748y4ea6ba39kd663508042740722@mail.gmail.com>

Hello,

But of course the following is the problem:

Index: fold-const.c

*** fold-const.c (revision 121992) --- fold-const.c (working copy) *************** tree_swap_operands_p (tree arg0, tree ar *** 6668,6676 **** && (TREE_SIDE_EFFECTS (arg0) || TREE_SIDE_EFFECTS (arg1))) return 0;

! if (DECL_P (arg1)) return 0; ! if (DECL_P (arg0)) return 1;

/* It is preferable to swap two SSA_NAME to ensure a canonical form --- 6668,6676 ---- && (TREE_SIDE_EFFECTS (arg0) || TREE_SIDE_EFFECTS (arg1))) return 0;

! if (DECL_P (arg1) || TREE_CODE (arg1) == SSA_NAME) return 0; ! if (DECL_P (arg0) || TREE_CODE (arg0) == SSA_NAME) return 1;

/* It is preferable to swap two SSA_NAME to ensure a canonical form

I'll bootstrap and test it.

makes sense, although it won't fix the problem in general (e.g., 2 * a < 2 * a + 4 still would not be folded).

Zdenek

• Follow-Ups:
  • Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv
    * From: Richard Guenther
• References:
  • Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv
    * From: Zdenek Dvorak
  • Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv
    * From: Christian BRUEL
  • Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv
    * From: Zdenek Dvorak
  • Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv
    * From: Christian BRUEL
  • Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv
    * From: Richard Guenther
  • Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv
    * From: Zdenek Dvorak
  • Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv
    * From: Richard Guenther
  • Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv
    * From: Zdenek Dvorak
  • Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv
    * From: Richard Guenther
  • Re: [patch] (-fstrict-overflow) optimize counted loops on signed iv
    * From: Richard Guenther