On 04/17/2017 09:57 AM, Denys Vlasenko wrote:
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 246948)
+++ gcc/doc/invoke.texi (working copy)
@@ -351,9 +351,11 @@ Objective-C and Objective-C++ Dialects}.
@item Optimization Options
@xref{Optimize Options,,Options that Control Optimization}.
-@gccoptlist{-faggressive-loop-optimizations -falign-functions[=@var{n}] @gol
--falign-jumps[=@var{n}] @gol
--falign-labels[=@var{n}] -falign-loops[=@var{n}] @gol
+@gccoptlist{-faggressive-loop-optimizations @gol
+-falign-functions[=@var{n}[,@var{m},[@var{n2}[,@var{m2}]]]] @gol
+-falign-jumps[=@var{n}[,@var{m},[@var{n2}[,@var{m2}]]]] @gol
+-falign-labels[=@var{n}[,@var{m},[@var{n2}[,@var{m2}]]]] @gol
+-falign-loops[=@var{n}[,@var{m},[@var{n2}[,@var{m2}]]]] @gol
-fassociative-math -fauto-profile -fauto-profile[=@var{path}] @gol
-fauto-inc-dec -fbranch-probabilities @gol
-fbranch-target-load-optimize -fbranch-target-load-optimize2 @gol
@@ -8672,19 +8674,36 @@ The @option{-fstrict-overflow} option is enabled a
@item -falign-functions
@itemx -falign-functions=@var{n}
+@itemx -falign-functions=@var{n},@var{m}
+@itemx -falign-functions=@var{n},@var{m},@var{n2}
+@itemx -falign-functions=@var{n},@var{m},@var{n2},@var{m2}
@opindex falign-functions
Align the start of functions to the next power-of-two greater than
-@var{n}, skipping up to @var{n} bytes. For instance,
-@option{-falign-functions=32} aligns functions to the next 32-byte
-boundary, but @option{-falign-functions=24} aligns to the next
-32-byte boundary only if this can be done by skipping 23 bytes or less.
+@var{n}, skipping up to @var{m}-1 bytes. Such alignment ensures that
+after branch, at least @var{m} bytes can be fetched by the CPU
+without crossing specified alignment boundary.
This last sentence doesn't make much sense to me. How about something like
This ensures that at least the first @var{m} bytes of the function can
be fetched by the CPU without crossing an @var{n}-byte alignment boundary.
-@option{-fno-align-functions} and @option{-falign-functions=1} are
-equivalent and mean that functions are not aligned.
+If @var{m} is not specified, it defaults to @var{n}.
+Same for @var{m2} and @var{n2}.
You haven't said what m2 and n2 are yet. The last sentence should be
moved to the end of this paragraph instead.
+The second pair of @var{n2},@var{m2} values allows to have a secondary
+alignment: @option{-falign-functions=64,7,32,3} aligns to the next
+64-byte boundary if this can be done by skipping 6 bytes or less,
+otherwise aligns to the next 32-byte boundary if this can be done
+by skipping 2 bytes or less.
Also please
s/allows to have/allows you to specify/
@@ -8697,12 +8716,13 @@ skip more bytes than the size of the function.
@item -falign-labels
@itemx -falign-labels=@var{n}
+@itemx -falign-labels=@var{n},@var{m}
+@itemx -falign-labels=@var{n},@var{m},@var{n2}
+@itemx -falign-labels=@var{n},@var{m},@var{n2},@var{m2}
@opindex falign-labels
-Align all branch targets to a power-of-two boundary, skipping up to
-@var{n} bytes like @option{-falign-functions}. This option can easily
-make code slower, because it must insert dummy operations for when the
-branch target is reached in the usual flow of the code.
+Align all branch targets to a power-of-two boundary.
+Parameters of this option are analogous to @option{-falign-functions} option.
s/to @option/to the @option/
Here and for -falign-loops and -falign-jumps too.
-Sandra
