| Message ID | 20180125215820.GS2063@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | Fix -Wrestrict SSA_NAME handling (PR c/83989) | expand |
On Thu, 25 Jan 2018, Jakub Jelinek wrote: > Hi! > > builtin_memref ctor for a SSA_NAME with non-NULL SSA_NAME_VAR returns > the underlying variable, rather than just the SSA_NAME. > Later on the code checks if the bases are equal and then compares > corresponding offsets. > > The fact that two different SSA_NAMEs have the same underlying variable > says nothing at all whether they have the same value, as the testcase shows, > either the SSA_NAMEs can be completely unrelated, or related, but with > different offsets. The code already has code to handle POINTER_PLUS_EXPR > with a constant offset, to look through that. Perhaps in the future there > can be other cases we'd special case, but generally we should compare as > bases the SSA_NAMEs, if they have the same or different base says nothing > about them. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? OK. Richard. > 2018-01-25 Jakub Jelinek <jakub@redhat.com> > > PR c/83989 > * gimple-ssa-warn-restrict.c (builtin_memref::builtin_memref): Don't > use SSA_NAME_VAR as base for SSA_NAMEs with non-NULL SSA_NAME_VAR. > > * c-c++-common/Wrestrict-3.c: New test. > > --- gcc/gimple-ssa-warn-restrict.c.jj 2018-01-17 11:54:17.000000000 +0100 > +++ gcc/gimple-ssa-warn-restrict.c 2018-01-25 14:10:26.182498552 +0100 > @@ -373,9 +373,6 @@ builtin_memref::builtin_memref (tree exp > offrange[1] += off; > } > } > - > - if (TREE_CODE (base) == SSA_NAME && SSA_NAME_VAR (base)) > - base = SSA_NAME_VAR (base); > } > > if (size) > --- gcc/testsuite/c-c++-common/Wrestrict-3.c.jj 2018-01-25 14:16:01.574563425 +0100 > +++ gcc/testsuite/c-c++-common/Wrestrict-3.c 2018-01-25 14:14:39.273547506 +0100 > @@ -0,0 +1,48 @@ > +/* PR c/83989 */ > +/* { dg-do compile } */ > +/* { dg-options "-O2 -Wrestrict" } */ > + > +__attribute__((__malloc__)) extern void *my_malloc (__SIZE_TYPE__); > +void baz (void *); > + > +#define SIZE 32 > + > +void > +foo (void) > +{ > + void *recmem = __builtin_malloc (SIZE); > + baz (recmem); > + while (1) > + { > + void *oldrecmem = recmem; > + recmem = __builtin_malloc (SIZE); > + if (!recmem) > + { > + __builtin_free (oldrecmem); > + return; > + } > + __builtin_memcpy (recmem, oldrecmem, SIZE); /* { dg-bogus "accessing" } */ > + baz (recmem); > + __builtin_free (oldrecmem); > + } > +} > + > +void > +bar (void) > +{ > + void *recmem = my_malloc (SIZE); > + baz (recmem); > + while (1) > + { > + void *oldrecmem = recmem; > + recmem = my_malloc (SIZE); > + if (!recmem) > + { > + __builtin_free (oldrecmem); > + return; > + } > + __builtin_memcpy (recmem, oldrecmem, SIZE); /* { dg-bogus "accessing" } */ > + baz (recmem); > + __builtin_free (oldrecmem); > + } > +} > > Jakub > >
--- gcc/gimple-ssa-warn-restrict.c.jj 2018-01-17 11:54:17.000000000 +0100 +++ gcc/gimple-ssa-warn-restrict.c 2018-01-25 14:10:26.182498552 +0100 @@ -373,9 +373,6 @@ builtin_memref::builtin_memref (tree exp offrange[1] += off; } } - - if (TREE_CODE (base) == SSA_NAME && SSA_NAME_VAR (base)) - base = SSA_NAME_VAR (base); } if (size) --- gcc/testsuite/c-c++-common/Wrestrict-3.c.jj 2018-01-25 14:16:01.574563425 +0100 +++ gcc/testsuite/c-c++-common/Wrestrict-3.c 2018-01-25 14:14:39.273547506 +0100 @@ -0,0 +1,48 @@ +/* PR c/83989 */ +/* { dg-do compile } */ +/* { dg-options "-O2 -Wrestrict" } */ + +__attribute__((__malloc__)) extern void *my_malloc (__SIZE_TYPE__); +void baz (void *); + +#define SIZE 32 + +void +foo (void) +{ + void *recmem = __builtin_malloc (SIZE); + baz (recmem); + while (1) + { + void *oldrecmem = recmem; + recmem = __builtin_malloc (SIZE); + if (!recmem) + { + __builtin_free (oldrecmem); + return; + } + __builtin_memcpy (recmem, oldrecmem, SIZE); /* { dg-bogus "accessing" } */ + baz (recmem); + __builtin_free (oldrecmem); + } +} + +void +bar (void) +{ + void *recmem = my_malloc (SIZE); + baz (recmem); + while (1) + { + void *oldrecmem = recmem; + recmem = my_malloc (SIZE); + if (!recmem) + { + __builtin_free (oldrecmem); + return; + } + __builtin_memcpy (recmem, oldrecmem, SIZE); /* { dg-bogus "accessing" } */ + baz (recmem); + __builtin_free (oldrecmem); + } +}