https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87829
Bug ID: 87829
Summary: Contradiction about -fReorder-Blocks
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: web
Assignee: unassigned at gcc dot gnu.org
Reporter: mcccs at gmx dot com
Target Milestone: ---
On this page: https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html
(invoke.texi)
It says:
@option{-Os} disables the following optimization flags:
@gccoptlist{-falign-functions -falign-jumps -falign-loops @gol
-falign-labels -freorder-blocks -freorder-blocks-algorithm=stc @gol
-freorder-blocks-and-partition -fprefetch-loop-arrays}
If you scroll down, it says:
@item -freorder-blocks
@opindex freorder-blocks
Reorder basic blocks in the compiled function in order to reduce number of
taken branches and improve code locality.
Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
Is it enabled in -Os or not? They contradict.
Also for -freorder-blocks-algorithm and -freorder-blocks-and-partition
