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| author | Janis Johnson <janis187@us.ibm.com> | 2007-11-01 16:34:48 +0000 |
|---|---|---|
| committer | Janis Johnson <janis@gcc.gnu.org> | 2007-11-01 16:34:48 +0000 |
| commit | d6a64b9df961ae0e885a50a6b01fb2b846e60f12 (patch) | |
| tree | d605b3933ec62f86f88dfcf370532453edb2d759 /gcc/doc | |
| parent | fdaea7e2865fc020c80fcd8093175b5a20ed0507 (diff) | |
| download | gcc-d6a64b9df961ae0e885a50a6b01fb2b846e60f12.zip gcc-d6a64b9df961ae0e885a50a6b01fb2b846e60f12.tar.gz gcc-d6a64b9df961ae0e885a50a6b01fb2b846e60f12.tar.bz2 | |
invoke.texi (Optimize Options): Under -fcse-follow-jumps, show that CSE means common subexpression elimination.
* doc/invoke.texi (Optimize Options): Under -fcse-follow-jumps,
show that CSE means common subexpression elimination. Change wording
for -fsee and define LCM. Remove capitalization of optimizations
for -ftree-reassoc, -ftree-pre, and -ftree-fre.
From-SVN: r129824
Diffstat (limited to 'gcc/doc')
| -rw-r--r-- | gcc/doc/invoke.texi | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index b98d70c..4de20b6 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -5399,7 +5399,7 @@ Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @item -fcse-follow-jumps @opindex fcse-follow-jumps -In common subexpression elimination, scan through jump instructions +In common subexpression elimination (CSE), scan through jump instructions when the target of the jump is not reached by any other path. For example, when CSE encounters an @code{if} statement with an @code{else} clause, CSE will follow the jump when the condition @@ -5644,8 +5644,8 @@ sense when scheduling after register allocation, i.e.@: with @item -fsee @opindex fsee -Eliminates redundant extension instructions and move the non redundant -ones to optimal placement using LCM. +Eliminate redundant sign extension instructions and move the non-redundant +ones to optimal placement using lazy code motion (LCM). @item -freschedule-modulo-scheduled-loops @opindex freschedule-modulo-scheduled-loops @@ -5667,17 +5667,17 @@ Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. @item -ftree-reassoc @opindex ftree-reassoc -Perform Reassociation on trees This flag is enabled by default +Perform reassociation on trees. This flag is enabled by default at @option{-O} and higher. @item -ftree-pre @opindex ftree-pre -Perform Partial Redundancy Elimination (PRE) on trees. This flag is +Perform partial redundancy elimination (PRE) on trees. This flag is enabled by default at @option{-O2} and @option{-O3}. @item -ftree-fre @opindex ftree-fre -Perform Full Redundancy Elimination (FRE) on trees. The difference +Perform full redundancy elimination (FRE) on trees. The difference between FRE and PRE is that FRE only considers expressions that are computed on all paths leading to the redundant computation. This analysis is faster than PRE, though it exposes fewer redundancies. |