Hi,
I just noticed that some of my libraries are greater when compiled with gcc
4.4.3 instead of gcc 4.3.2. Diffing the output of "gcc --help=optimizers -Q
-Os" shows this in 4.3.2:
-falign-jumps [disabled]
-falign-labels [disabled]
-falign-loops [enabled]
and this for 4.4.3:
-falign-functions [enabled]
-falign-jumps [enabled]
-falign-labels [enabled]
-falign-loops [disabled]
when explicitely disabling the alignment options then the code size shrinks.
For libxml2 in my case from 704256 to 675584 bytes.
The manual says:
-Os disables the following optimization flags: -falign-functions
-falign-jumps -falign-loops -falign-labels -freorder-blocks
-freorder-blocks-and-partition -fprefetch-loop-arrays
-ftree-vect-loop-version
which is not true (even not for 4.3.2 since loop alignment was enabled). Some
other opts like -freorder-blocks is enabled as well.
So is this actually a bug or is the documentation outdated or even both?
--
Summary: -Os creates larger binaries than before in some cases (-
falign-... options enabled)
Product: gcc
Version: 4.4.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: rwahl at gmx dot de
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43861
