Message ID | 1278534137-22733-2-git-send-email-sebpop@gmail.com |
---|---|
State | New |
Headers | show |
On Wed, Jul 7, 2010 at 10:22 PM, Sebastian Pop <sebpop@gmail.com> wrote: > * common.opt (floop-if-convert): New flag. > * doc/invoke.texi (floop-if-convert): Documented. > * tree-if-conv.c (gate_tree_if_conversion): Enable if-conversion > when flag_loop_if_convert is set. > --- > gcc/common.opt | 4 ++++ > gcc/doc/invoke.texi | 10 ++++++++-- > gcc/tree-if-conv.c | 3 ++- > 3 files changed, 14 insertions(+), 3 deletions(-) > > diff --git a/gcc/common.opt b/gcc/common.opt > index 6ca787a..2a5d391 100644 > --- a/gcc/common.opt > +++ b/gcc/common.opt > @@ -653,6 +653,10 @@ fif-conversion2 > Common Report Var(flag_if_conversion2) Optimization > Perform conversion of conditional jumps to conditional execution > > +floop-if-convert > +Common Report Var(flag_loop_if_convert) Optimization > +Convert conditional jumps in innermost loops to branchless equivalents > + Init(0) is missing. Also can you name it -ftree-loop-if-conversion instead consistent with -ftree-loop-* and -fif-conversion. There is still no way to disable if-conversion if the vectorizer is enabled, so I guess a tri-state -1, disabled and enabled would be more useful (as you wanted it for debugging in the first place). Richard. > ; -finhibit-size-directive inhibits output of .size for ELF. > ; This is used only for compiling crtstuff.c, > ; and it may be extended to other effects > diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi > index d70f130..da14bf9 100644 > --- a/gcc/doc/invoke.texi > +++ b/gcc/doc/invoke.texi > @@ -342,7 +342,7 @@ Objective-C and Objective-C++ Dialects}. > -fearly-inlining -fipa-sra -fexpensive-optimizations -ffast-math @gol > -ffinite-math-only -ffloat-store -fexcess-precision=@var{style} @gol > -fforward-propagate -ffunction-sections @gol > --fgcse -fgcse-after-reload -fgcse-las -fgcse-lm @gol > +-fgcse -fgcse-after-reload -fgcse-las -fgcse-lm -fgraphite-identity @gol > -fgcse-sm -fif-conversion -fif-conversion2 -findirect-inlining @gol > -finline-functions -finline-functions-called-once -finline-limit=@var{n} @gol > -finline-small-functions -fipa-cp -fipa-cp-clone -fipa-matrix-reorg -fipa-pta @gol > @@ -352,7 +352,7 @@ Objective-C and Objective-C++ Dialects}. > -fira-loop-pressure -fno-ira-share-save-slots @gol > -fno-ira-share-spill-slots -fira-verbose=@var{n} @gol > -fivopts -fkeep-inline-functions -fkeep-static-consts @gol > --floop-block -floop-interchange -floop-strip-mine -fgraphite-identity @gol > +-floop-block -floop-if-convert -floop-interchange -floop-strip-mine @gol > -floop-parallelize-all -flto -flto-compression-level -flto-report -fltrans @gol > -fltrans-output-list -fmerge-all-constants -fmerge-constants -fmodulo-sched @gol > -fmodulo-sched-allow-regmoves -fmove-loop-invariants -fmudflap @gol > @@ -6883,6 +6883,12 @@ profitable to parallelize the loops. > Compare the results of several data dependence analyzers. This option > is used for debugging the data dependence analyzers. > > +@item -floop-if-convert > +Attempt to transform conditional jumps in the innermost loops to > +branch-less equivalents. The intent is to remove control-flow from > +the innermost loops in order to improve the ability of the > +auto-vectorization pass to handle these loops. > + > @item -ftree-loop-distribution > Perform loop distribution. This flag can improve cache performance on > big loop bodies and allow further loop optimizations, like > diff --git a/gcc/tree-if-conv.c b/gcc/tree-if-conv.c > index 8d5d226..ad106d7 100644 > --- a/gcc/tree-if-conv.c > +++ b/gcc/tree-if-conv.c > @@ -1242,7 +1242,8 @@ main_tree_if_conversion (void) > static bool > gate_tree_if_conversion (void) > { > - return flag_tree_vectorize != 0; > + return flag_tree_vectorize > + || flag_loop_if_convert; > } > > struct gimple_opt_pass pass_if_conversion = > -- > 1.7.0.4 > >
On Wed, Jul 7, 2010 at 16:39, Richard Guenther <richard.guenther@gmail.com> wrote: > On Wed, Jul 7, 2010 at 10:22 PM, Sebastian Pop <sebpop@gmail.com> wrote: >> * common.opt (floop-if-convert): New flag. >> * doc/invoke.texi (floop-if-convert): Documented. >> * tree-if-conv.c (gate_tree_if_conversion): Enable if-conversion >> when flag_loop_if_convert is set. >> --- >> gcc/common.opt | 4 ++++ >> gcc/doc/invoke.texi | 10 ++++++++-- >> gcc/tree-if-conv.c | 3 ++- >> 3 files changed, 14 insertions(+), 3 deletions(-) >> >> diff --git a/gcc/common.opt b/gcc/common.opt >> index 6ca787a..2a5d391 100644 >> --- a/gcc/common.opt >> +++ b/gcc/common.opt >> @@ -653,6 +653,10 @@ fif-conversion2 >> Common Report Var(flag_if_conversion2) Optimization >> Perform conversion of conditional jumps to conditional execution >> >> +floop-if-convert >> +Common Report Var(flag_loop_if_convert) Optimization >> +Convert conditional jumps in innermost loops to branchless equivalents >> + > > Init(0) is missing. Also can you name it -ftree-loop-if-conversion instead > consistent with -ftree-loop-* and -fif-conversion. > Ok, I will do this. Although, I do not like the "tree" in the flags, as I find that there is no reason to expose the internals of GCC to GCC users. > There is still no way to disable if-conversion if the vectorizer is enabled, > so I guess a tri-state -1, disabled and enabled would be more useful > (as you wanted it for debugging in the first place). > Good idea. I will post an updated patch with these modifications. Sebastian
diff --git a/gcc/common.opt b/gcc/common.opt index 6ca787a..2a5d391 100644 --- a/gcc/common.opt +++ b/gcc/common.opt @@ -653,6 +653,10 @@ fif-conversion2 Common Report Var(flag_if_conversion2) Optimization Perform conversion of conditional jumps to conditional execution +floop-if-convert +Common Report Var(flag_loop_if_convert) Optimization +Convert conditional jumps in innermost loops to branchless equivalents + ; -finhibit-size-directive inhibits output of .size for ELF. ; This is used only for compiling crtstuff.c, ; and it may be extended to other effects diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index d70f130..da14bf9 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -342,7 +342,7 @@ Objective-C and Objective-C++ Dialects}. -fearly-inlining -fipa-sra -fexpensive-optimizations -ffast-math @gol -ffinite-math-only -ffloat-store -fexcess-precision=@var{style} @gol -fforward-propagate -ffunction-sections @gol --fgcse -fgcse-after-reload -fgcse-las -fgcse-lm @gol +-fgcse -fgcse-after-reload -fgcse-las -fgcse-lm -fgraphite-identity @gol -fgcse-sm -fif-conversion -fif-conversion2 -findirect-inlining @gol -finline-functions -finline-functions-called-once -finline-limit=@var{n} @gol -finline-small-functions -fipa-cp -fipa-cp-clone -fipa-matrix-reorg -fipa-pta @gol @@ -352,7 +352,7 @@ Objective-C and Objective-C++ Dialects}. -fira-loop-pressure -fno-ira-share-save-slots @gol -fno-ira-share-spill-slots -fira-verbose=@var{n} @gol -fivopts -fkeep-inline-functions -fkeep-static-consts @gol --floop-block -floop-interchange -floop-strip-mine -fgraphite-identity @gol +-floop-block -floop-if-convert -floop-interchange -floop-strip-mine @gol -floop-parallelize-all -flto -flto-compression-level -flto-report -fltrans @gol -fltrans-output-list -fmerge-all-constants -fmerge-constants -fmodulo-sched @gol -fmodulo-sched-allow-regmoves -fmove-loop-invariants -fmudflap @gol @@ -6883,6 +6883,12 @@ profitable to parallelize the loops. Compare the results of several data dependence analyzers. This option is used for debugging the data dependence analyzers. +@item -floop-if-convert +Attempt to transform conditional jumps in the innermost loops to +branch-less equivalents. The intent is to remove control-flow from +the innermost loops in order to improve the ability of the +auto-vectorization pass to handle these loops. + @item -ftree-loop-distribution Perform loop distribution. This flag can improve cache performance on big loop bodies and allow further loop optimizations, like diff --git a/gcc/tree-if-conv.c b/gcc/tree-if-conv.c index 8d5d226..ad106d7 100644 --- a/gcc/tree-if-conv.c +++ b/gcc/tree-if-conv.c @@ -1242,7 +1242,8 @@ main_tree_if_conversion (void) static bool gate_tree_if_conversion (void) { - return flag_tree_vectorize != 0; + return flag_tree_vectorize + || flag_loop_if_convert; } struct gimple_opt_pass pass_if_conversion =