diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/doc/invoke.texi | 13 |
2 files changed, 14 insertions, 5 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 9f83f36..bb1d5d4 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2016-03-07 Martin Sebor <msebor@redhat.com> + + PR rtl-optimization/19705 + * doc/invoke.texi (Options That Control Optimization): Clarify + -fno-branch-count-reg. + 2016-02-26 Richard Biener <rguenther@suse.de> Jeff Law <law@redhat.com> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 4b5df0b..e9d21a3 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -6541,11 +6541,14 @@ life-range analysis. This option is effective only with @item -fno-branch-count-reg @opindex fno-branch-count-reg -Do not use ``decrement and branch'' instructions on a count register, -but instead generate a sequence of instructions that decrement a -register, compare it against zero, then branch based upon the result. -This option is only meaningful on architectures that support such -instructions, which include x86, PowerPC, IA-64 and S/390. +Avoid running a pass scanning for opportunities to use ``decrement and +branch'' instructions on a count register instead of generating sequences +of instructions that decrement a register, compare it against zero, and +then branch based upon the result. This option is only meaningful on +architectures that support such instructions, which include x86, PowerPC, +IA-64 and S/390. Note that the @option{-fno-branch-count-reg} option +doesn't remove the decrement and branch instructions from the generated +instruction stream introduced by other optimization passes. Enabled by default at @option{-O1} and higher. |