From 4ca0d6d449a0884cbd24bcc87c91253ba093487c Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Fri, 12 Sep 2003 15:52:24 +0000 Subject: [PATCH] * loop.c: Move comments describing BIV's and GIV's to top of file From-SVN: r71333 --- gcc/ChangeLog | 4 ++++ gcc/loop.c | 20 ++++++++++---------- 2 files changed, 14 insertions(+), 10 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index eb5e258df6e5..45fbeec9c32a 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +2003-09-12 Chris Lattner + + * loop.c: Move comments describing BIV's and GIV's to top of file + 2003-09-12 Roger Sayle PR optimization/8967 diff --git a/gcc/loop.c b/gcc/loop.c index 31592fc2ba1c..2866ce0cb4b7 100644 --- a/gcc/loop.c +++ b/gcc/loop.c @@ -22,8 +22,16 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA /* This is the loop optimization pass of the compiler. It finds invariant computations within loops and moves them to the beginning of the loop. Then it identifies basic and - general induction variables. Strength reduction is applied to the general - induction variables, and induction variable elimination is applied to + general induction variables. + + Basic induction variables (BIVs) are a pseudo registers which are set within + a loop only by incrementing or decrementing its value. General induction + variables (GIVs) are pseudo registers with a value which is a linear function + of a basic induction variable. BIVs are recognized by `basic_induction_var'; + GIVs by `general_induction_var'. + + Once induction variables are identified, strength reduction is applied to the + general induction variables, and induction variable elimination is applied to the basic induction variables. It also finds cases where @@ -4223,14 +4231,6 @@ emit_prefetch_instructions (struct loop *loop) return; } -/* A "basic induction variable" or biv is a pseudo reg that is set - (within this loop) only by incrementing or decrementing it. */ -/* A "general induction variable" or giv is a pseudo reg whose - value is a linear function of a biv. */ - -/* Bivs are recognized by `basic_induction_var'; - Givs by `general_induction_var'. */ - /* Communication with routines called via `note_stores'. */ static rtx note_insn; -- 2.47.2