diff options
Diffstat (limited to 'gcc/doc/passes.texi')
| -rw-r--r-- | gcc/doc/passes.texi | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/gcc/doc/passes.texi b/gcc/doc/passes.texi index 8ca8f8b..423434d 100644 --- a/gcc/doc/passes.texi +++ b/gcc/doc/passes.texi @@ -459,13 +459,20 @@ The option @option{-dS} causes a debugging dump of the RTL code after this pass is run for the first time. The dump file's name is made by appending @samp{.sched} to the input file name. +@cindex register allocation +@item +Register allocation. These passes make sure that all occurences of pseudo +registers are eliminated, either by allocating them to a hard register, +replacing them by an equivalent expression (e.g.@: a constant) or by placing +them on the stack. This is done in several subpasses: + +@itemize @bullet @cindex register class preference pass @item Register class preferencing. The RTL code is scanned to find out which register class is best for each pseudo register. The source file is @file{regclass.c}. -@cindex register allocation @cindex local register allocation @item Local register allocation (@file{local-alloc.c}). This pass allocates @@ -484,6 +491,17 @@ Global register allocation (@file{global.c}). This pass allocates hard registers for the remaining pseudo registers (those whose life spans are not contained in one basic block). +@cindex graph coloring register allocation +@opindex fnew-ra +@opindex dl +@item +Graph coloring register allocator. The files @file{ra.c}, @file{ra-build.c}, +@file{ra-colorize.c}, @file{ra-debug.c}, @file{ra-rewrite.c} together with +the header @file{ra.h} contain another register allocator, which is used +when the option @option{-fnew-ra} is given. In that case it is run instead +of the above mentioned local and global register allocation passes, and the +option @option{-dl} causes a debugging dump of its work. + @cindex reloading @item Reloading. This pass renumbers pseudo registers with the hardware @@ -505,6 +523,7 @@ Source files are @file{reload.c} and @file{reload1.c}, plus the header The option @option{-dg} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.greg} to the input file name. +@end itemize @cindex instruction scheduling @cindex scheduling, instruction |