| Message ID | ri6o7s6rp25.fsf@suse.cz |
|---|---|
| State | New |
| Headers | show |
| Series | ipa-sra: Consider the first parameter of methods safe to dereference | expand |
> Hi, > > Honza requested this after reviewing the patch that taught IPA-SRA > that REFERENCE_TYPEs are always non-NULL that the pass also handles > the first parameters of methods, this pointers, in the same way. So > this patch does that. > > The patch is undergoing bootstrap and testing on an x86_64-linux right > now. OK if it passes? > > Thanks, > > Martin > > > gcc/ChangeLog: > > 2022-12-14 Martin Jambor <mjambor@suse.cz> > > * ipa-sra.cc (create_parameter_descriptors): Consider the first > parameter of a method safe to dereference. > > gcc/testsuite/ChangeLog: > > 2022-12-14 Martin Jambor <mjambor@suse.cz> > > * g++.dg/ipa/ipa-sra-6.C: New test. OK, thanks a lot! Honza
On Wed, Dec 14, 2022 at 4:20 PM Jan Hubicka via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > > Hi, > > > > Honza requested this after reviewing the patch that taught IPA-SRA > > that REFERENCE_TYPEs are always non-NULL that the pass also handles > > the first parameters of methods, this pointers, in the same way. So > > this patch does that. > > > > The patch is undergoing bootstrap and testing on an x86_64-linux right > > now. OK if it passes? > > > > Thanks, > > > > Martin > > > > > > gcc/ChangeLog: > > > > 2022-12-14 Martin Jambor <mjambor@suse.cz> > > > > * ipa-sra.cc (create_parameter_descriptors): Consider the first > > parameter of a method safe to dereference. > > > > gcc/testsuite/ChangeLog: > > > > 2022-12-14 Martin Jambor <mjambor@suse.cz> > > > > * g++.dg/ipa/ipa-sra-6.C: New test. > > OK, Are you sure that's safe? The docs for METHOD_TYPE doesn't say 'this' is the first parameter nor does it say methods cannot be invoked for a nullptr object. Do frontends other than C++ create METHOD_TYPE functions? Grep shows uses in ada and objective C at least. > thanks a lot! > Honza
> On Wed, Dec 14, 2022 at 4:20 PM Jan Hubicka via Gcc-patches > <gcc-patches@gcc.gnu.org> wrote: > > > > > Hi, > > > > > > Honza requested this after reviewing the patch that taught IPA-SRA > > > that REFERENCE_TYPEs are always non-NULL that the pass also handles > > > the first parameters of methods, this pointers, in the same way. So > > > this patch does that. > > > > > > The patch is undergoing bootstrap and testing on an x86_64-linux right > > > now. OK if it passes? > > > > > > Thanks, > > > > > > Martin > > > > > > > > > gcc/ChangeLog: > > > > > > 2022-12-14 Martin Jambor <mjambor@suse.cz> > > > > > > * ipa-sra.cc (create_parameter_descriptors): Consider the first > > > parameter of a method safe to dereference. > > > > > > gcc/testsuite/ChangeLog: > > > > > > 2022-12-14 Martin Jambor <mjambor@suse.cz> > > > > > > * g++.dg/ipa/ipa-sra-6.C: New test. > > > > OK, > > Are you sure that's safe? The docs for METHOD_TYPE doesn't say 'this' > is the first parameter nor does it say methods cannot be invoked for a > nullptr object. > > Do frontends other than C++ create METHOD_TYPE functions? Grep > shows uses in ada and objective C at least. I think for Objective-C++ calling method is also considerd a dereference. We make similar assumptions in devirtualization code for some time. We could also check that the type is METHOD_TYPE satisfies odr_type_p if we want to look specifically for C++ methods. Honza > > > thanks a lot! > > Honza
diff --git a/gcc/ipa-sra.cc b/gcc/ipa-sra.cc index bcabdedfc6c..6fe336eeb19 100644 --- a/gcc/ipa-sra.cc +++ b/gcc/ipa-sra.cc @@ -1206,7 +1206,12 @@ create_parameter_descriptors (cgraph_node *node, if (POINTER_TYPE_P (type)) { desc->by_ref = true; - desc->safe_ref = (TREE_CODE (type) == REFERENCE_TYPE); + if (TREE_CODE (type) == REFERENCE_TYPE + || (num == 0 + && TREE_CODE (TREE_TYPE (node->decl)) == METHOD_TYPE)) + desc->safe_ref = true; + else + desc->safe_ref = false; type = TREE_TYPE (type); if (TREE_CODE (type) == FUNCTION_TYPE diff --git a/gcc/testsuite/g++.dg/ipa/ipa-sra-6.C b/gcc/testsuite/g++.dg/ipa/ipa-sra-6.C new file mode 100644 index 00000000000..d6b7822533f --- /dev/null +++ b/gcc/testsuite/g++.dg/ipa/ipa-sra-6.C @@ -0,0 +1,62 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-ipa-sra" } */ + +namespace { + +class C +{ + + int mi; + +public: + C (int i) + : mi(i) + {} + + void foo (int c); +}; + +volatile int vi; + + +void __attribute__((noinline)) +C::foo (int cond) +{ + int i; + if (cond) + i = mi; + else + i = 0; + vi = i; +} + +static C c_instance(1); +} + +void __attribute__((noinline)) +bar (C *p, int cond) +{ + p->foo (cond); +} + + +class C *gp; + +void something(void); + +void +baz (int cond) +{ + C c(vi); + gp = &c; + something (); + bar (gp, cond); +} + +void +hoo(void) +{ + gp = &c_instance; +} + +/* { dg-final { scan-ipa-dump "Will split parameter" "sra" } } */