| Message ID | HE1PR0801MB1755F8212E0C116A6FB0E28FE7090@HE1PR0801MB1755.eurprd08.prod.outlook.com |
|---|---|
| State | New |
| Headers | show |
On Thu, Jul 21, 2016 at 04:50:31PM +0000, Bin Cheng wrote: > Hi, > This patch adds new option -Wmissed-loop-optimizations warning on loops whose counter may overflow, as well as makes -Wunsafe-loop-optimizations an alias to the new option. > Bootstrap and test on x86_64 ongoing. Is it OK? I'm repeating myself and since we already have a warning for this it might make sense to continue having one, but shouldn't we be trying to move towards the -fopt-info mechanism for optimization feedback? We already seem to have OPTGROUP_LOOP even, so could you perhaps consider also adding a call to dump_printf_loc (MSG_MISSED_OPTIMIZATION, loc, text) ? Thanks, Martin > > Thanks, > bin > > 2016-07-20 Bin Cheng <bin.cheng@arm.com> > > * common.opt (Wmissed-loop-optimizations): New option. > (Wunsafe-loop-optimizations): Alias to Wmissed-loop-optimizations. > * doc/invoke.texi (Wmissed-loop-optimizations): Ditto. > (Wunsafe-loop-optimizations): Alias to Wmissed-loop-optimizations. > * tree-ssa-loop-niter.c (number_of_iterations_exit): Use option > Wmissed-loop-optimizations. > diff --git a/gcc/common.opt b/gcc/common.opt > index 8a292ed..3d62657 100644 > --- a/gcc/common.opt > +++ b/gcc/common.opt > @@ -625,7 +625,12 @@ Common Var(warn_null_dereference) Warning > Warn if dereferencing a NULL pointer may lead to erroneous or undefined behavior. > > Wunsafe-loop-optimizations > -Common Var(warn_unsafe_loop_optimizations) Warning > +Common Alias(Wmissed-loop-optimizations) > +Warn if the loop cannot be optimized due to nontrivial assumptions. > +Same as -Wmissed-loop-optimizations. > + > +Wmissed-loop-optimizations > +Common Var(warn_missed_loop_optimizations) Warning > Warn if the loop cannot be optimized due to nontrivial assumptions. > > Wmissing-noreturn > diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi > index 3041c18..5a2bb09 100644 > --- a/gcc/doc/invoke.texi > +++ b/gcc/doc/invoke.texi > @@ -302,8 +302,8 @@ Objective-C and Objective-C++ Dialects}. > -Wswitch -Wswitch-bool -Wswitch-default -Wswitch-enum @gol > -Wswitch-unreachable -Wsync-nand @gol > -Wsystem-headers -Wtautological-compare -Wtrampolines -Wtrigraphs @gol > --Wtype-limits -Wundef @gol > --Wuninitialized -Wunknown-pragmas -Wunsafe-loop-optimizations @gol > +-Wtype-limits -Wundef -Wuninitialized -Wunknown-pragmas @gol > +-Wmissed-loop-optimizations -Wunsafe-loop-optimizations @gol > -Wunsuffixed-float-constants -Wunused -Wunused-function @gol > -Wunused-label -Wunused-local-typedefs -Wunused-parameter @gol > -Wno-unused-result -Wunused-value @gol -Wunused-variable @gol > @@ -4990,9 +4990,14 @@ If the stack usage is (partly) dynamic and not bounded, it's: > @opindex Wunsafe-loop-optimizations > @opindex Wno-unsafe-loop-optimizations > Warn if the loop cannot be optimized because the compiler cannot > -assume anything on the bounds of the loop indices. With > -@option{-funsafe-loop-optimizations} warn if the compiler makes > -such assumptions. > +assume anything on the bounds of the loop indices. Same as > +@option{-Wmissed-loop-optimizations}. > + > +@item -Wmissed-loop-optimizations > +@opindex Wmissed-loop-optimizations > +@opindex Wno-missed-loop-optimizations > +Warn if the loop cannot be optimized because the compiler cannot > +assume anything on the bounds of the loop indices. > > @item -Wno-pedantic-ms-format @r{(MinGW targets only)} > @opindex Wno-pedantic-ms-format > diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c > index 2061eafa..38b5552 100644 > --- a/gcc/tree-ssa-loop-niter.c > +++ b/gcc/tree-ssa-loop-niter.c > @@ -2333,7 +2333,7 @@ number_of_iterations_exit (struct loop *loop, edge exit, > > wording = N_("missed loop optimization, the loop counter may overflow"); > warning_at ((LOCATION_LINE (loc) > 0) ? loc : input_location, > - OPT_Wunsafe_loop_optimizations, "%s", gettext (wording)); > + OPT_Wmissed_loop_optimizations, "%s", gettext (wording)); > } > > return false;
On Fri, Jul 22, 2016 at 9:48 AM, Martin Jambor <mjambor@suse.cz> wrote: > On Thu, Jul 21, 2016 at 04:50:31PM +0000, Bin Cheng wrote: >> Hi, >> This patch adds new option -Wmissed-loop-optimizations warning on loops whose counter may overflow, as well as makes -Wunsafe-loop-optimizations an alias to the new option. >> Bootstrap and test on x86_64 ongoing. Is it OK? > > I'm repeating myself and since we already have a warning for this it > might make sense to continue having one, but shouldn't we be trying to > move towards the -fopt-info mechanism for optimization feedback? We > already seem to have OPTGROUP_LOOP even, so could you perhaps consider > also adding a call to > > dump_printf_loc (MSG_MISSED_OPTIMIZATION, loc, text) > > ? Hmm, in this way I will see if I can change this single patch and add warning message in opt-info category. Thanks, bin > > Thanks, > > Martin >
diff --git a/gcc/common.opt b/gcc/common.opt index 8a292ed..3d62657 100644 --- a/gcc/common.opt +++ b/gcc/common.opt @@ -625,7 +625,12 @@ Common Var(warn_null_dereference) Warning Warn if dereferencing a NULL pointer may lead to erroneous or undefined behavior. Wunsafe-loop-optimizations -Common Var(warn_unsafe_loop_optimizations) Warning +Common Alias(Wmissed-loop-optimizations) +Warn if the loop cannot be optimized due to nontrivial assumptions. +Same as -Wmissed-loop-optimizations. + +Wmissed-loop-optimizations +Common Var(warn_missed_loop_optimizations) Warning Warn if the loop cannot be optimized due to nontrivial assumptions. Wmissing-noreturn diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 3041c18..5a2bb09 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -302,8 +302,8 @@ Objective-C and Objective-C++ Dialects}. -Wswitch -Wswitch-bool -Wswitch-default -Wswitch-enum @gol -Wswitch-unreachable -Wsync-nand @gol -Wsystem-headers -Wtautological-compare -Wtrampolines -Wtrigraphs @gol --Wtype-limits -Wundef @gol --Wuninitialized -Wunknown-pragmas -Wunsafe-loop-optimizations @gol +-Wtype-limits -Wundef -Wuninitialized -Wunknown-pragmas @gol +-Wmissed-loop-optimizations -Wunsafe-loop-optimizations @gol -Wunsuffixed-float-constants -Wunused -Wunused-function @gol -Wunused-label -Wunused-local-typedefs -Wunused-parameter @gol -Wno-unused-result -Wunused-value @gol -Wunused-variable @gol @@ -4990,9 +4990,14 @@ If the stack usage is (partly) dynamic and not bounded, it's: @opindex Wunsafe-loop-optimizations @opindex Wno-unsafe-loop-optimizations Warn if the loop cannot be optimized because the compiler cannot -assume anything on the bounds of the loop indices. With -@option{-funsafe-loop-optimizations} warn if the compiler makes -such assumptions. +assume anything on the bounds of the loop indices. Same as +@option{-Wmissed-loop-optimizations}. + +@item -Wmissed-loop-optimizations +@opindex Wmissed-loop-optimizations +@opindex Wno-missed-loop-optimizations +Warn if the loop cannot be optimized because the compiler cannot +assume anything on the bounds of the loop indices. @item -Wno-pedantic-ms-format @r{(MinGW targets only)} @opindex Wno-pedantic-ms-format diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c index 2061eafa..38b5552 100644 --- a/gcc/tree-ssa-loop-niter.c +++ b/gcc/tree-ssa-loop-niter.c @@ -2333,7 +2333,7 @@ number_of_iterations_exit (struct loop *loop, edge exit, wording = N_("missed loop optimization, the loop counter may overflow"); warning_at ((LOCATION_LINE (loc) > 0) ? loc : input_location, - OPT_Wunsafe_loop_optimizations, "%s", gettext (wording)); + OPT_Wmissed_loop_optimizations, "%s", gettext (wording)); } return false;