| Message ID | 1637303593-31949-1-git-send-email-apinski@marvell.com |
|---|---|
| State | New |
| Headers | show |
| Series | Fix tree-optimization/103314 : Limit folding of (type) X op CST where type is a nop convert to gimple | expand |
On Fri, Nov 19, 2021 at 7:34 AM apinski--- via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > From: Andrew Pinski <apinski@marvell.com> > > There is some re-association code in fold_binary which conflicts with > this optimization due keeping around some "constants" which are not > INTEGER_CST (1 << -1) so we end up in an infinite loop because of that. > So we need to limit this case to GIMPLE level only. > > OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions. OK. Richard. > PR tree-optimization/103314 > > gcc/ChangeLog: > > * match.pd ((type) X op CST): Restrict the equal > TYPE_PRECISION case to GIMPLE only. > > gcc/testsuite/ChangeLog: > > * gcc.c-torture/compile/pr103314-1.c: New test. > --- > gcc/match.pd | 6 +++++- > gcc/testsuite/gcc.c-torture/compile/pr103314-1.c | 6 ++++++ > 2 files changed, 11 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr103314-1.c > > diff --git a/gcc/match.pd b/gcc/match.pd > index 4dc66fb47f2..24a84e3b504 100644 > --- a/gcc/match.pd > +++ b/gcc/match.pd > @@ -1619,7 +1619,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) > after hoisting the conversion the operation will be narrower. > It is also a good if the conversion is a nop as moves the > conversion to one side; allowing for combining of the conversions. */ > - TYPE_PRECISION (TREE_TYPE (@0)) <= TYPE_PRECISION (type) > + TYPE_PRECISION (TREE_TYPE (@0)) < TYPE_PRECISION (type) > + /* The conversion check for being a nop can only be done at the gimple > + level as fold_binary has some re-association code which can conflict > + with this if there is a "constant" which is not a full INTEGER_CST. */ > + || (GIMPLE && TYPE_PRECISION (TREE_TYPE (@0)) == TYPE_PRECISION (type)) > /* It's also a good idea if the conversion is to a non-integer > mode. */ > || GET_MODE_CLASS (TYPE_MODE (type)) != MODE_INT > diff --git a/gcc/testsuite/gcc.c-torture/compile/pr103314-1.c b/gcc/testsuite/gcc.c-torture/compile/pr103314-1.c > new file mode 100644 > index 00000000000..f4a63130421 > --- /dev/null > +++ b/gcc/testsuite/gcc.c-torture/compile/pr103314-1.c > @@ -0,0 +1,6 @@ > +/* { dg-options "" } */ > +int main() { > + int t = 1; > + unsigned c = 0, d1 = t ? 1 ^ c ^ 1 >> (-1) : 0; /* { dg-warning "is negative" } */ > + return d1; > +} > -- > 2.17.1 >
diff --git a/gcc/match.pd b/gcc/match.pd index 4dc66fb47f2..24a84e3b504 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -1619,7 +1619,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) after hoisting the conversion the operation will be narrower. It is also a good if the conversion is a nop as moves the conversion to one side; allowing for combining of the conversions. */ - TYPE_PRECISION (TREE_TYPE (@0)) <= TYPE_PRECISION (type) + TYPE_PRECISION (TREE_TYPE (@0)) < TYPE_PRECISION (type) + /* The conversion check for being a nop can only be done at the gimple + level as fold_binary has some re-association code which can conflict + with this if there is a "constant" which is not a full INTEGER_CST. */ + || (GIMPLE && TYPE_PRECISION (TREE_TYPE (@0)) == TYPE_PRECISION (type)) /* It's also a good idea if the conversion is to a non-integer mode. */ || GET_MODE_CLASS (TYPE_MODE (type)) != MODE_INT diff --git a/gcc/testsuite/gcc.c-torture/compile/pr103314-1.c b/gcc/testsuite/gcc.c-torture/compile/pr103314-1.c new file mode 100644 index 00000000000..f4a63130421 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/compile/pr103314-1.c @@ -0,0 +1,6 @@ +/* { dg-options "" } */ +int main() { + int t = 1; + unsigned c = 0, d1 = t ? 1 ^ c ^ 1 >> (-1) : 0; /* { dg-warning "is negative" } */ + return d1; +}
From: Andrew Pinski <apinski@marvell.com> There is some re-association code in fold_binary which conflicts with this optimization due keeping around some "constants" which are not INTEGER_CST (1 << -1) so we end up in an infinite loop because of that. So we need to limit this case to GIMPLE level only. OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions. PR tree-optimization/103314 gcc/ChangeLog: * match.pd ((type) X op CST): Restrict the equal TYPE_PRECISION case to GIMPLE only. gcc/testsuite/ChangeLog: * gcc.c-torture/compile/pr103314-1.c: New test. --- gcc/match.pd | 6 +++++- gcc/testsuite/gcc.c-torture/compile/pr103314-1.c | 6 ++++++ 2 files changed, 11 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr103314-1.c