From 26315ccfd8de46cbaa6aa64289b998aaf8b2bd8d Mon Sep 17 00:00:00 2001 From: Sebastian Pop Date: Thu, 30 Sep 2010 21:20:52 +0000 Subject: [PATCH] Fix comments. 2010-09-09 Sebastian Pop * graphite-flattening.c: Fix comments. From-SVN: r164805 --- gcc/ChangeLog | 4 ++++ gcc/ChangeLog.graphite | 4 ++++ gcc/graphite-flattening.c | 10 ++++++++-- 3 files changed, 16 insertions(+), 2 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index e0268cf66c6..1c08e8d29be 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +2010-09-30 Sebastian Pop + + * graphite-flattening.c: Fix comments. + 2010-09-30 Sebastian Pop * Makefile.in (OBJS-common): Add graphite-flattening.o. diff --git a/gcc/ChangeLog.graphite b/gcc/ChangeLog.graphite index 7e0e8871269..00ab0051394 100644 --- a/gcc/ChangeLog.graphite +++ b/gcc/ChangeLog.graphite @@ -1,3 +1,7 @@ +2010-09-09 Sebastian Pop + + * graphite-flattening.c: Fix comments. + 2010-09-09 Sebastian Pop * Makefile.in (OBJS-common): Add graphite-flattening.o. diff --git a/gcc/graphite-flattening.c b/gcc/graphite-flattening.c index 0f9833710b0..c026ffc227a 100644 --- a/gcc/graphite-flattening.c +++ b/gcc/graphite-flattening.c @@ -55,6 +55,12 @@ along with GCC; see the file COPYING3. If not see then apply on the full loop body, without needing the outer-loop vectorization. + The loop flattening pass that has been described in a very Fortran + specific way in the 1992 paper by Reinhard von Hanxleden and Ken + Kennedy: "Relaxing SIMD Control Flow Constraints using Loop + Transformations" available from + http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.54.5033 + The canonical example is as follows: suppose that we have a loop nest with known iteration counts @@ -95,11 +101,11 @@ along with GCC; see the file COPYING3. If not see | } | } - For an arbitrarily complex loop nests the algorithm proceeds in two + For an arbitrarily complex loop nest the algorithm proceeds in two steps. First, the LST is flattened by removing the loops structure and by inserting the statements in the order they appear in depth-first order. Then, the scattering of each statement is - transformed such that it + transformed accordingly. Supposing that the original program is represented by the following LST: