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[DOC] cleanups for optimization options
- From: Janis Johnson <janis187 at us dot ibm dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Tue, 30 Oct 2007 16:26:30 -0700
- Subject: [DOC] cleanups for optimization options
- Reply-to: janis187 at us dot ibm dot com
Minor cleanups for documentation of optimization options. Tested with
make dvi/info/html/pdf; OK for mainline?
2007-10-30 Janis Johnson <janis187@us.ibm.com>
* 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.
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 129787)
+++ gcc/doc/invoke.texi (working copy)
@@ -5399,7 +5399,7 @@
@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 @@
@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 @@
@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.