On Wed, May 17, 2023 at 2:54 AM Andrew Pinski via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > The problem here is that VRP cannot figure out isize could not be 0 > due to using integer_zerop. This patch removes the use of integer_zerop > and instead checks for 0 directly after converting the tree to > an unsigned HOST_WIDE_INT. This allows VRP to figure out isize is not 0 > and `isize - 1` will always be >= 0. > > This patch is just to avoid the warning that GCC could produce sometimes > and does not change any code generation or even VRP. > > OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
OK. Richard. > gcc/ChangeLog: > > * tree-ssa-forwprop.cc (simplify_builtin_call): Check > against 0 instead of calling integer_zerop. > --- > gcc/tree-ssa-forwprop.cc | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc > index 06f19868ade..0326e6733e8 100644 > --- a/gcc/tree-ssa-forwprop.cc > +++ b/gcc/tree-ssa-forwprop.cc > @@ -1231,14 +1231,14 @@ simplify_builtin_call (gimple_stmt_iterator *gsi_p, > tree callee2) > tree size = gimple_call_arg (stmt2, 2); > /* Size must be a constant which is <= UNITS_PER_WORD and > <= the string length. */ > - if (TREE_CODE (size) != INTEGER_CST || integer_zerop (size)) > + if (TREE_CODE (size) != INTEGER_CST) > break; > > if (!tree_fits_uhwi_p (size)) > break; > > unsigned HOST_WIDE_INT sz = tree_to_uhwi (size); > - if (sz > UNITS_PER_WORD || sz >= slen) > + if (sz == 0 || sz > UNITS_PER_WORD || sz >= slen) > break; > > tree ch = gimple_call_arg (stmt2, 1); > -- > 2.31.1 >
