Message ID | 20241002031236.1448655-1-quic_apinski@quicinc.com |
---|---|
State | New |
Headers | show |
Series | backprop: Fix deleting of a phi node [PR116922] | expand |
On Wed, Oct 2, 2024 at 5:13 AM Andrew Pinski <quic_apinski@quicinc.com> wrote: > > The problem here is remove_unused_var is called on a name that is > defined by a phi node but it deletes it like removing a normal statement. > remove_phi_node should be called rather than gsi_remove for phinodes. > > Note there is a possibility of using simple_dce_from_worklist instead > but that is for another day. > > Bootstrapped and tested on x86_64-linux-gnu. OK (not that I like the two conflicting APIs, maybe we can work towards removing remove_phi_node and make PHI node handling in gsi_* better) Thanks, Richard. > PR tree-optimization/116922 > > gcc/ChangeLog: > > * gimple-ssa-backprop.cc (remove_unused_var): Handle phi > nodes correctly. > > gcc/testsuite/ChangeLog: > > * gcc.dg/torture/pr116922.c: New test. > > Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com> > --- > gcc/gimple-ssa-backprop.cc | 10 ++++++++-- > gcc/testsuite/gcc.dg/torture/pr116922.c | 19 +++++++++++++++++++ > 2 files changed, 27 insertions(+), 2 deletions(-) > create mode 100644 gcc/testsuite/gcc.dg/torture/pr116922.c > > diff --git a/gcc/gimple-ssa-backprop.cc b/gcc/gimple-ssa-backprop.cc > index fe27ef51cdf..e3374b18138 100644 > --- a/gcc/gimple-ssa-backprop.cc > +++ b/gcc/gimple-ssa-backprop.cc > @@ -663,8 +663,14 @@ remove_unused_var (tree var) > print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); > } > gimple_stmt_iterator gsi = gsi_for_stmt (stmt); > - gsi_remove (&gsi, true); > - release_defs (stmt); > + if (gimple_code (stmt) == GIMPLE_PHI) > + remove_phi_node (&gsi, true); > + else > + { > + unlink_stmt_vdef (stmt); > + gsi_remove (&gsi, true); > + release_defs (stmt); > + } > } > > /* Note that we're replacing OLD_RHS with NEW_RHS in STMT. */ > diff --git a/gcc/testsuite/gcc.dg/torture/pr116922.c b/gcc/testsuite/gcc.dg/torture/pr116922.c > new file mode 100644 > index 00000000000..0fcf912930f > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/torture/pr116922.c > @@ -0,0 +1,19 @@ > +/* { dg-do compile } */ > +/* { dg-additional-options "-ffast-math" } */ > +/* PR tree-optimization/116922 */ > + > + > +static int g; > + > +void > +foo (int c, double v, double *r) > +{ > +b: > + do > + v /= g - v; > + while (c); > + *r = v; > + > + double x; > + foo (5, (double)0, &x); > +} > -- > 2.43.0 >
diff --git a/gcc/gimple-ssa-backprop.cc b/gcc/gimple-ssa-backprop.cc index fe27ef51cdf..e3374b18138 100644 --- a/gcc/gimple-ssa-backprop.cc +++ b/gcc/gimple-ssa-backprop.cc @@ -663,8 +663,14 @@ remove_unused_var (tree var) print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } gimple_stmt_iterator gsi = gsi_for_stmt (stmt); - gsi_remove (&gsi, true); - release_defs (stmt); + if (gimple_code (stmt) == GIMPLE_PHI) + remove_phi_node (&gsi, true); + else + { + unlink_stmt_vdef (stmt); + gsi_remove (&gsi, true); + release_defs (stmt); + } } /* Note that we're replacing OLD_RHS with NEW_RHS in STMT. */ diff --git a/gcc/testsuite/gcc.dg/torture/pr116922.c b/gcc/testsuite/gcc.dg/torture/pr116922.c new file mode 100644 index 00000000000..0fcf912930f --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr116922.c @@ -0,0 +1,19 @@ +/* { dg-do compile } */ +/* { dg-additional-options "-ffast-math" } */ +/* PR tree-optimization/116922 */ + + +static int g; + +void +foo (int c, double v, double *r) +{ +b: + do + v /= g - v; + while (c); + *r = v; + + double x; + foo (5, (double)0, &x); +}
The problem here is remove_unused_var is called on a name that is defined by a phi node but it deletes it like removing a normal statement. remove_phi_node should be called rather than gsi_remove for phinodes. Note there is a possibility of using simple_dce_from_worklist instead but that is for another day. Bootstrapped and tested on x86_64-linux-gnu. PR tree-optimization/116922 gcc/ChangeLog: * gimple-ssa-backprop.cc (remove_unused_var): Handle phi nodes correctly. gcc/testsuite/ChangeLog: * gcc.dg/torture/pr116922.c: New test. Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com> --- gcc/gimple-ssa-backprop.cc | 10 ++++++++-- gcc/testsuite/gcc.dg/torture/pr116922.c | 19 +++++++++++++++++++ 2 files changed, 27 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/torture/pr116922.c