This patch is for PR23197, a complaint dating back to 2005 that the
documentation for the options enabled by -fprofile-generate and
-fprofile-use was bit-rotten. Well, it was even more bit-rotten by now.
:-P I updated the docs to reflect the current code in opts.c and
also fixed -fauto-profile, which shares much of the same logic.
-Sandra
2018-11-16 Sandra Loosemore <san...@codesourcery.com>
PR middle-end/23197
gcc/
* doc/invoke.texi (Optimize Options): Update options enabled by
fprofile-generate, -fprofile-use, and -fauto-profile.
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 266229)
+++ gcc/doc/invoke.texi (working copy)
@@ -8412,7 +8412,8 @@ If all calls to a given function are int
declared @code{static}, then the function is normally not output as
assembler code in its own right.
-Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. Also enabled
+by @option{-fprofile-use} and @option{-fauto-profile}.
@item -finline-functions-called-once
@opindex finline-functions-called-once
@@ -8671,6 +8672,8 @@ When @option{-fgcse-after-reload} is ena
pass is performed after reload. The purpose of this pass is to clean up
redundant spilling.
+Enabled by @option{-fprofile-use} and @option{-fauto-profile}.
+
@item -faggressive-loop-optimizations
@opindex faggressive-loop-optimizations
This option tells the loop optimizer to use language constraints to
@@ -9241,6 +9244,7 @@ to functions are constants and then opti
This optimization can substantially increase performance
if the application has constants passed to functions.
This flag is enabled by default at @option{-O2}, @option{-Os} and @option{-O3}.
+It is also enabled by @option{-fprofile-use} and @option{-fauto-profile}.
@item -fipa-cp-clone
@opindex fipa-cp-clone
@@ -9251,12 +9255,14 @@ Because this optimization can create mul
it may significantly increase code size
(see @option{--param ipcp-unit-growth=@var{value}}).
This flag is enabled by default at @option{-O3}.
+It is also enabled by @option{-fprofile-use} and @option{-fauto-profile}.
@item -fipa-bit-cp
@opindex fipa-bit-cp
When enabled, perform interprocedural bitwise constant
-propagation. This flag is enabled by default at @option{-O2}. It
-requires that @option{-fipa-cp} is enabled.
+propagation. This flag is enabled by default at @option{-O2} and
+by @option{-fprofile-use} and @option{-fauto-profile}.
+It requires that @option{-fipa-cp} is enabled.
@item -fipa-vrp
@opindex fipa-vrp
@@ -9455,7 +9461,8 @@ ENDDO
@item -ftree-loop-distribute-patterns
@opindex ftree-loop-distribute-patterns
Perform loop distribution of patterns that can be code generated with
-calls to a library. This flag is enabled by default at @option{-O3}.
+calls to a library. This flag is enabled by default at @option{-O3}, and
+by @option{-fprofile-use} and @option{-fauto-profile}.
This pass distributes the initialization loops and generates a call to
memset zero. For example, the loop
@@ -9584,12 +9591,14 @@ and @option{-ftree-slp-vectorize} if not
@item -ftree-loop-vectorize
@opindex ftree-loop-vectorize
Perform loop vectorization on trees. This flag is enabled by default at
-@option{-O3} and when @option{-ftree-vectorize} is enabled.
+@option{-O3} and by @option{-ftree-vectorize}, @option{-fprofile-use},
+and @option{-fauto-profile}.
@item -ftree-slp-vectorize
@opindex ftree-slp-vectorize
Perform basic block vectorization on trees. This flag is enabled by default at
-@option{-O3} and when @option{-ftree-vectorize} is enabled.
+@option{-O3} and by @option{-ftree-vectorize}, @option{-fprofile-use},
+and @option{-fauto-profile}.
@item -fvect-cost-model=@var{model}
@opindex fvect-cost-model
@@ -9663,6 +9672,7 @@ Perform predictive commoning optimizatio
iterations of loops.
This option is enabled at level @option{-O3}.
+It is also enabled by @option{-fprofile-use} and @option{-fauto-profile}.
@item -fprefetch-loop-arrays
@opindex fprefetch-loop-arrays
@@ -10276,15 +10286,22 @@ be inconsistent due to missed counter up
GCC uses heuristics to correct or smooth out such inconsistencies. By
default, GCC emits an error message when an inconsistent profile is detected.
+This option is enabled by @option{-fauto-profile}.
+
@item -fprofile-use
@itemx -fprofile-use=@var{path}
@opindex fprofile-use
Enable profile feedback-directed optimizations,
-and the following optimizations
-which are generally profitable only with profile feedback available:
-@option{-fbranch-probabilities}, @option{-fvpt},
-@option{-funroll-loops}, @option{-fpeel-loops}, @option{-ftracer},
-@option{-ftree-vectorize}, and @option{ftree-loop-distribute-patterns}.
+and the following optimizations, many of which
+are generally profitable only with profile feedback available:
+
+@gccoptlist{-fbranch-probabilities -fprofile-values @gol
+-funroll-loops -fpeel-loops -ftracer -fvpt @gol
+-finline-functions -fipa-cp -fipa-cp-clone -fipa-bit-cp @gol
+-fpredictive-commoning -fsplit-loops -funswitch-loops @gol
+-fgcse-after-reload -ftree-loop-vectorize -ftree-slp-vectorize @gol
+-fvect-cost-model=dynamic -ftree-loop-distribute-patterns @gol
+-fprofile-reorder-functions}
Before you can use this option, you must first generate profiling information.
@xref{Instrumentation Options}, for information about the
@@ -10294,7 +10311,7 @@ By default, GCC emits an error message i
match the source code. This error can be turned into a warning by using
@option{-Wno-error=coverage-mismatch}. Note this may result in poorly
optimized code. Additionally, by default, GCC also emits a warning message if
-the feedback profiles do not exist (See @option{-Wmissing-profile}).
+the feedback profiles do not exist (see @option{-Wmissing-profile}).
If @var{path} is specified, GCC looks at the @var{path} to find
the profile feedback data files. See @option{-fprofile-dir}.
@@ -10303,14 +10320,16 @@ the profile feedback data files. See @op
@itemx -fauto-profile=@var{path}
@opindex fauto-profile
Enable sampling-based feedback-directed optimizations,
-and the following optimizations
-which are generally profitable only with profile feedback available:
-@option{-fbranch-probabilities}, @option{-fvpt},
-@option{-funroll-loops}, @option{-fpeel-loops}, @option{-ftracer},
-@option{-ftree-vectorize},
-@option{-finline-functions}, @option{-fipa-cp}, @option{-fipa-cp-clone},
-@option{-fpredictive-commoning}, @option{-funswitch-loops},
-@option{-fgcse-after-reload}, and @option{-ftree-loop-distribute-patterns}.
+and the following optimizations,
+many of which are generally profitable only with profile feedback available:
+
+@gccoptlist{-fbranch-probabilities -fprofile-values @gol
+-funroll-loops -fpeel-loops -ftracer -fvpt @gol
+-finline-functions -fipa-cp -fipa-cp-clone -fipa-bit-cp @gol
+-fpredictive-commoning -fsplit-loops -funswitch-loops @gol
+-fgcse-after-reload -ftree-loop-vectorize -ftree-slp-vectorize @gol
+-fvect-cost-model=dynamic -ftree-loop-distribute-patterns @gol
+-fprofile-correction}
@var{path} is the name of a file containing AutoFDO profile information.
If omitted, it defaults to @file{fbdata.afdo} in the current directory.
@@ -10613,6 +10632,8 @@ used in one place: in @file{reorg.c}, in
branch is most likely to take, the @samp{REG_BR_PROB} values are used to
exactly determine which path is taken more often.
+Enabled by @option{-fprofile-use} and @option{-fauto-profile}.
+
@item -fprofile-values
@opindex fprofile-values
If combined with @option{-fprofile-arcs}, it adds code so that some
@@ -10621,7 +10642,8 @@ data about values of expressions in the
With @option{-fbranch-probabilities}, it reads back the data gathered
from profiling values of expressions for usage in optimizations.
-Enabled with @option{-fprofile-generate} and @option{-fprofile-use}.
+Enabled by @option{-fprofile-generate}, @option{-fprofile-use}, and
+@option{-fauto-profile}.
@item -fprofile-reorder-functions
@opindex fprofile-reorder-functions
@@ -10641,6 +10663,8 @@ and actually performs the optimizations
Currently the optimizations include specialization of division operations
using the knowledge about the value of the denominator.
+Enabled with @option{-fprofile-use} and @option{-fauto-profile}.
+
@item -frename-registers
@opindex frename-registers
Attempt to avoid false dependencies in scheduled code by making use
@@ -10666,7 +10690,7 @@ Perform tail duplication to enlarge supe
simplifies the control flow of the function allowing other optimizations to do
a better job.
-Enabled with @option{-fprofile-use}.
+Enabled by @option{-fprofile-use} and @option{-fauto-profile}.
@item -funroll-loops
@opindex funroll-loops
@@ -10677,7 +10701,7 @@ It also turns on complete loop peeling (
a small constant number of iterations). This option makes code larger, and may
or may not make it run faster.
-Enabled with @option{-fprofile-use}.
+Enabled by @option{-fprofile-use} and @option{-fauto-profile}.
@item -funroll-all-loops
@opindex funroll-all-loops
@@ -10693,7 +10717,7 @@ roll much (from profile feedback or stat
complete loop peeling (i.e.@: complete removal of loops with small constant
number of iterations).
-Enabled with @option{-O3} and/or @option{-fprofile-use}.
+Enabled by @option{-O3}, @option{-fprofile-use}, and @option{-fauto-profile}.
@item -fmove-loop-invariants
@opindex fmove-loop-invariants
@@ -10705,11 +10729,15 @@ at level @option{-O1} and higher, except
Split a loop into two if it contains a condition that's always true
for one side of the iteration space and false for the other.
+Enabled by @option{-fprofile-use} and @option{-fauto-profile}.
+
@item -funswitch-loops
@opindex funswitch-loops
Move branches with loop invariant conditions out of the loop, with duplicates
of the loop on both branches (modified according to result of the condition).
+Enabled by @option{-fprofile-use} and @option{-fauto-profile}.
+
@item -ffunction-sections
@itemx -fdata-sections
@opindex ffunction-sections
@@ -12096,7 +12124,9 @@ profile useful for later recompilation w
optimization. You must use @option{-fprofile-generate} both when
compiling and when linking your program.
-The following options are enabled: @option{-fprofile-arcs}, @option{-fprofile-values}, @option{-fvpt}.
+The following options are enabled:
+@option{-fprofile-arcs}, @option{-fprofile-values},
+@option{-finline-functions}, and @option{-fipa-bit-cp}.
If @var{path} is specified, GCC looks at the @var{path} to find
the profile feedback data files. See @option{-fprofile-dir}.
