| Message ID | 20230221191036.1140927-1-ppalka@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: more mce_false folding from cp_fully_fold_init [PR108243] | expand |
On 2/21/23 14:10, Patrick Palka wrote: > We should also fold the overall initializer passed to cp_fully_fold_init > with mce_false, which enables folding of the copy-initialization of > 'a1' in the below testcase (the initializer here is an AGGR_INIT_EXPR). > > Unfortunately this doesn't help with direct- or default-initialization > because we don't call cp_fully_fold_init in that case, and even if we > did the initializer in that case is expressed as a bare CALL_EXPR > instead of an AGGR_INIT_EXPR, which cp_fully_fold_init can't really > fold. > > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for > trunk? OK. > PR c++/108243 > > gcc/cp/ChangeLog: > > * cp-gimplify.cc (cp_fully_fold): Add an internal overload that > additionally takes and propagate an mce_value parameter, and > define the existing public overload in terms of it. > (cp_fully_fold_init): Pass mce_false to cp_fully_fold. > > gcc/testsuite/ChangeLog: > > * g++.dg/opt/is_constant_evaluated3.C: New test. > --- > gcc/cp/cp-gimplify.cc | 14 +++++++---- > .../g++.dg/opt/is_constant_evaluated3.C | 23 +++++++++++++++++++ > 2 files changed, 33 insertions(+), 4 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/opt/is_constant_evaluated3.C > > diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc > index 32fe53521cc..5d5c6efb856 100644 > --- a/gcc/cp/cp-gimplify.cc > +++ b/gcc/cp/cp-gimplify.cc > @@ -2447,8 +2447,8 @@ cp_fold_rvalue (tree x) > > /* Perform folding on expression X. */ > > -tree > -cp_fully_fold (tree x) > +static tree > +cp_fully_fold (tree x, mce_value manifestly_const_eval) > { > if (processing_template_decl) > return x; > @@ -2456,7 +2456,7 @@ cp_fully_fold (tree x) > have to call both. */ > if (cxx_dialect >= cxx11) > { > - x = maybe_constant_value (x); > + x = maybe_constant_value (x, /*decl=*/NULL_TREE, manifestly_const_eval); > /* Sometimes we are given a CONSTRUCTOR but the call above wraps it into > a TARGET_EXPR; undo that here. */ > if (TREE_CODE (x) == TARGET_EXPR) > @@ -2469,6 +2469,12 @@ cp_fully_fold (tree x) > return cp_fold_rvalue (x); > } > > +tree > +cp_fully_fold (tree x) > +{ > + return cp_fully_fold (x, mce_unknown); > +} > + > /* Likewise, but also fold recursively, which cp_fully_fold doesn't perform > in some cases. */ > > @@ -2477,7 +2483,7 @@ cp_fully_fold_init (tree x) > { > if (processing_template_decl) > return x; > - x = cp_fully_fold (x); > + x = cp_fully_fold (x, mce_false); > cp_fold_data data (ff_mce_false); > cp_walk_tree (&x, cp_fold_r, &data, NULL); > return x; > diff --git a/gcc/testsuite/g++.dg/opt/is_constant_evaluated3.C b/gcc/testsuite/g++.dg/opt/is_constant_evaluated3.C > new file mode 100644 > index 00000000000..0a1e46e5638 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/opt/is_constant_evaluated3.C > @@ -0,0 +1,23 @@ > +// PR c++/108243 > +// { dg-do compile { target c++11 } } > +// { dg-additional-options "-O -fdump-tree-original" } > + > +struct A { > + constexpr A(int n) : n(n), m(__builtin_is_constant_evaluated()) { } > + constexpr A() : A(42) { } > + int n, m; > +}; > + > +int main() { > + A a1 = {42}; > + A a2{42}; > + A a3(42); > + A a4; > + A a5{}; > +} > + > +// { dg-final { scan-tree-dump "a1 = {\\.n=42, \\.m=0}" "original" } } > +// { dg-final { scan-tree-dump "a2 = {\\.n=42, \\.m=0}" "original" { xfail *-*-* } } } > +// { dg-final { scan-tree-dump "a3 = {\\.n=42, \\.m=0}" "original" { xfail *-*-* } } } > +// { dg-final { scan-tree-dump "a4 = {\\.n=42, \\.m=0}" "original" { xfail *-*-* } } } > +// { dg-final { scan-tree-dump "a5 = {\\.n=42, \\.m=0}" "original" { xfail *-*-* } } }
diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc index 32fe53521cc..5d5c6efb856 100644 --- a/gcc/cp/cp-gimplify.cc +++ b/gcc/cp/cp-gimplify.cc @@ -2447,8 +2447,8 @@ cp_fold_rvalue (tree x) /* Perform folding on expression X. */ -tree -cp_fully_fold (tree x) +static tree +cp_fully_fold (tree x, mce_value manifestly_const_eval) { if (processing_template_decl) return x; @@ -2456,7 +2456,7 @@ cp_fully_fold (tree x) have to call both. */ if (cxx_dialect >= cxx11) { - x = maybe_constant_value (x); + x = maybe_constant_value (x, /*decl=*/NULL_TREE, manifestly_const_eval); /* Sometimes we are given a CONSTRUCTOR but the call above wraps it into a TARGET_EXPR; undo that here. */ if (TREE_CODE (x) == TARGET_EXPR) @@ -2469,6 +2469,12 @@ cp_fully_fold (tree x) return cp_fold_rvalue (x); } +tree +cp_fully_fold (tree x) +{ + return cp_fully_fold (x, mce_unknown); +} + /* Likewise, but also fold recursively, which cp_fully_fold doesn't perform in some cases. */ @@ -2477,7 +2483,7 @@ cp_fully_fold_init (tree x) { if (processing_template_decl) return x; - x = cp_fully_fold (x); + x = cp_fully_fold (x, mce_false); cp_fold_data data (ff_mce_false); cp_walk_tree (&x, cp_fold_r, &data, NULL); return x; diff --git a/gcc/testsuite/g++.dg/opt/is_constant_evaluated3.C b/gcc/testsuite/g++.dg/opt/is_constant_evaluated3.C new file mode 100644 index 00000000000..0a1e46e5638 --- /dev/null +++ b/gcc/testsuite/g++.dg/opt/is_constant_evaluated3.C @@ -0,0 +1,23 @@ +// PR c++/108243 +// { dg-do compile { target c++11 } } +// { dg-additional-options "-O -fdump-tree-original" } + +struct A { + constexpr A(int n) : n(n), m(__builtin_is_constant_evaluated()) { } + constexpr A() : A(42) { } + int n, m; +}; + +int main() { + A a1 = {42}; + A a2{42}; + A a3(42); + A a4; + A a5{}; +} + +// { dg-final { scan-tree-dump "a1 = {\\.n=42, \\.m=0}" "original" } } +// { dg-final { scan-tree-dump "a2 = {\\.n=42, \\.m=0}" "original" { xfail *-*-* } } } +// { dg-final { scan-tree-dump "a3 = {\\.n=42, \\.m=0}" "original" { xfail *-*-* } } } +// { dg-final { scan-tree-dump "a4 = {\\.n=42, \\.m=0}" "original" { xfail *-*-* } } } +// { dg-final { scan-tree-dump "a5 = {\\.n=42, \\.m=0}" "original" { xfail *-*-* } } }