| Message ID | 20200824213703.GS2363@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | gimple: Ignore *0 = {CLOBBER} in path isolation [PR96722] | expand |
On Mon, 24 Aug 2020, Jakub Jelinek wrote: > Hi! > > Clobbers of MEM_REF with NULL address are just fancy nops, something we just > ignore and don't emit any code for it (ditto for other clobbers), they just > mark end of life on something, so we shouldn't infer from those that there > is some UB. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? OK. Richard. > 2020-08-24 Jakub Jelinek <jakub@redhat.com> > > PR tree-optimization/96722 > * gimple.c (infer_nonnull_range): Formatting fix. > (infer_nonnull_range_by_dereference): Return false for clobber stmts. > > * g++.dg/opt/pr96722.C: New test. > > --- gcc/gimple.c.jj 2020-08-03 22:54:51.417531677 +0200 > +++ gcc/gimple.c 2020-08-24 13:23:22.082312349 +0200 > @@ -2917,8 +2917,8 @@ check_loadstore (gimple *, tree op, tree > bool > infer_nonnull_range (gimple *stmt, tree op) > { > - return infer_nonnull_range_by_dereference (stmt, op) > - || infer_nonnull_range_by_attribute (stmt, op); > + return (infer_nonnull_range_by_dereference (stmt, op) > + || infer_nonnull_range_by_attribute (stmt, op)); > } > > /* Return true if OP can be inferred to be non-NULL after STMT > @@ -2930,7 +2930,8 @@ infer_nonnull_range_by_dereference (gimp > non-NULL if -fdelete-null-pointer-checks is enabled. */ > if (!flag_delete_null_pointer_checks > || !POINTER_TYPE_P (TREE_TYPE (op)) > - || gimple_code (stmt) == GIMPLE_ASM) > + || gimple_code (stmt) == GIMPLE_ASM > + || gimple_clobber_p (stmt)) > return false; > > if (walk_stmt_load_store_ops (stmt, (void *)op, > --- gcc/testsuite/g++.dg/opt/pr96722.C.jj 2020-08-24 13:24:45.357132323 +0200 > +++ gcc/testsuite/g++.dg/opt/pr96722.C 2020-08-24 13:25:06.224836626 +0200 > @@ -0,0 +1,20 @@ > +// PR tree-optimization/96722 > +// { dg-do run } > +// { dg-options "-O2" } > + > +struct S { int s; ~S () {} }; > + > +void > +foo (S *a) > +{ > + if (a) > + return; > + a->~S (); > +} > + > +int > +main () > +{ > + S s; > + foo (&s); > +} > > Jakub > >
--- gcc/gimple.c.jj 2020-08-03 22:54:51.417531677 +0200 +++ gcc/gimple.c 2020-08-24 13:23:22.082312349 +0200 @@ -2917,8 +2917,8 @@ check_loadstore (gimple *, tree op, tree bool infer_nonnull_range (gimple *stmt, tree op) { - return infer_nonnull_range_by_dereference (stmt, op) - || infer_nonnull_range_by_attribute (stmt, op); + return (infer_nonnull_range_by_dereference (stmt, op) + || infer_nonnull_range_by_attribute (stmt, op)); } /* Return true if OP can be inferred to be non-NULL after STMT @@ -2930,7 +2930,8 @@ infer_nonnull_range_by_dereference (gimp non-NULL if -fdelete-null-pointer-checks is enabled. */ if (!flag_delete_null_pointer_checks || !POINTER_TYPE_P (TREE_TYPE (op)) - || gimple_code (stmt) == GIMPLE_ASM) + || gimple_code (stmt) == GIMPLE_ASM + || gimple_clobber_p (stmt)) return false; if (walk_stmt_load_store_ops (stmt, (void *)op, --- gcc/testsuite/g++.dg/opt/pr96722.C.jj 2020-08-24 13:24:45.357132323 +0200 +++ gcc/testsuite/g++.dg/opt/pr96722.C 2020-08-24 13:25:06.224836626 +0200 @@ -0,0 +1,20 @@ +// PR tree-optimization/96722 +// { dg-do run } +// { dg-options "-O2" } + +struct S { int s; ~S () {} }; + +void +foo (S *a) +{ + if (a) + return; + a->~S (); +} + +int +main () +{ + S s; + foo (&s); +}