Trivial grammar fixes in the documentation.

[Joseph S. Myers]

One change to one of your fixes and some other issues noticed in the same 
paragraphs:

On Sat, 25 Apr 2009, Ralf Wildenhues wrote:

> @@ -2113,7 +2113,7 @@ comparisons, and so forth.
>  
>  These nodes represent fixed-point constants.  The type of these constants
>  is obtained with @code{TREE_TYPE}.  @code{TREE_FIXED_CST_PTR} points to
> -to struct fixed_value;  @code{TREE_FIXED_CST} returns the structure itself.
> +a struct fixed_value;  @code{TREE_FIXED_CST} returns the structure itself.
>  Struct fixed_value contains @code{data} with the size of two
>  HOST_BITS_PER_WIDE_INT and @code{mode} as the associated fixed-point

There are other problems there: @code{struct fixed_value} (twice), 
@code{HOST_BITS_PER_WIDE_INT}.

> @@ -3389,7 +3389,7 @@ The native AIX tools do interoperate with GCC@.
>  Building @file{libstdc++.a} requires a fix for an AIX Assembler bug
>  APAR IY26685 (AIX 4.3) or APAR IY25528 (AIX 5.1).  It also requires a
>  fix for another AIX Assembler bug and a co-dependent AIX Archiver fix
> -referenced as APAR IY53606 (AIX 5.2) or a APAR IY54774 (AIX 5.1)
> +referenced as APAR IY53606 (AIX 5.2) or an APAR IY54774 (AIX 5.1)

I think this should be "as" not "an".

> @@ -6211,7 +6211,7 @@ This flag is enabled by default at @option{-O3}.
>  @item -fipa-matrix-reorg
>  @opindex fipa-matrix-reorg
>  Perform matrix flattening and transposing.
> -Matrix flattening tries to replace a m-dimensional matrix 
> +Matrix flattening tries to replace an m-dimensional matrix
>  with its equivalent n-dimensional matrix, where n < m.
>  This reduces the level of indirection needed for accessing the elements
>  of the matrix. The second optimization is matrix transposing that

These would probably better use @math{m}, @math{n}, @math{n < m}.

-- 
Joseph S. Myers
joseph@codesourcery.com