From: Richard Biener <rguenther@suse.de>
Date: Mon, 28 Apr 2025 11:31:16 +0000 (+0200)
Subject: debug/78685 - reword -Og documentation
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3cf97980aaab6971ae179625a5e1188255dcf925;p=thirdparty%2Fgcc.git

debug/78685 - reword -Og documentation

The following rewords the documentation for -Og which over-promises
the ability to debug the generated code.  While -Og enables
var-tracking and thus improves debugging in some areas the experience
is usually worse than -O0 for standard C code.

	PR debug/78685
	* doc/invoke.texi (-Og): Reword.
---

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index d5a2bf6d02b..5f1c0b89c1c 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -12901,17 +12901,19 @@ It turns off @option{-fsemantic-interposition}.
 
 @opindex Og
 @item -Og
-Optimize debugging experience.  @option{-Og} should be the optimization
+Optimize while keeping in mind debugging experience.
+@option{-Og} should be the optimization
 level of choice for the standard edit-compile-debug cycle, offering
-a reasonable level of optimization while maintaining fast compilation
-and a good debugging experience.  It is a better choice than @option{-O0}
-for producing debuggable code because some compiler passes
-that collect debug information are disabled at @option{-O0}.
+a reasonable blend of optimization, fast compilation and debugging experience
+especially for code with a high abstraction penalty.  In contrast to
+@option{-O0}, this enables @option{-fvar-tracking-assignments} and
+@option{-fvar-tracking} which handle debug information in the prologue
+and epilogue of functions better than @option{-O0}.
 
-Like @option{-O0}, @option{-Og} completely disables a number of
+Like @option{-O0}, @option{-Og} completely skips a number of
 optimization passes so that individual options controlling them have
 no effect.  Otherwise @option{-Og} enables all @option{-O1}
-optimization flags except for those that may interfere with debugging:
+optimization flags except for those known to greatly interfere with debugging:
 
 @gccoptlist{-fbranch-count-reg  -fdelayed-branch
 -fdse  -fif-conversion  -fif-conversion2