On Fri, May 13, 2016 at 9:07 PM, Marc Glisse <marc.gli...@inria.fr> wrote:
> Hello,
>
> maybe this would fit better in VRP, but it is easier (and not completely
> useless) to put it in match.pd.
>
> Since the transformation is restricted to GIMPLE, I think I don't need to
> check that @0 is SSA_NAME. I didn't test if @0 has pointer type before
> calling get_range_info because we are doing bit_not on it, but it looks like
> I should because we can do bitops on pointers?
Yes, also because for odd reasons we may get constants into it here (which would
admittedly be a bug).
Thanks,
Richard.
> Adjustment for pr69270.c is exactly the same as in the previous patch from
> today :-)
>
> Bootstrap+regtest on powerpc64le-unknown-linux-gnu.
>
>
> 2016-05-16 Marc Glisse <marc.gli...@inria.fr>
>
> gcc/
> * match.pd (~X & Y): New transformation.
>
> gcc/testsuite/
> * gcc.dg/tree-ssa/pr69270.c: Adjust.
> * gcc.dg/tree-ssa/andnot-1.c: New testcase.
>
>
> --
> Marc Glisse
> Index: gcc/match.pd
> ===================================================================
> --- gcc/match.pd (revision 236194)
> +++ gcc/match.pd (working copy)
> @@ -496,20 +496,27 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> (minus @1 (bit_xor @0 @1)))
>
> /* Simplify (X & ~Y) | (~X & Y) -> X ^ Y. */
> (simplify
> (bit_ior (bit_and:c @0 (bit_not @1)) (bit_and:c (bit_not @0) @1))
> (bit_xor @0 @1))
> (simplify
> (bit_ior:c (bit_and @0 INTEGER_CST@2) (bit_and (bit_not @0)
> INTEGER_CST@1))
> (if (wi::bit_not (@2) == @1)
> (bit_xor @0 @1)))
> +/* Simplify (~X & Y) to X ^ Y if we know that (X & ~Y) is 0. */
> +#if GIMPLE
> +(simplify
> + (bit_and (bit_not @0) INTEGER_CST@1)
> + (if ((get_nonzero_bits (@0) & wi::bit_not (@1)) == 0)
> + (bit_xor @0 @1)))
> +#endif
>
> /* X % Y is smaller than Y. */
> (for cmp (lt ge)
> (simplify
> (cmp (trunc_mod @0 @1) @1)
> (if (TYPE_UNSIGNED (TREE_TYPE (@0)))
> { constant_boolean_node (cmp == LT_EXPR, type); })))
> (for cmp (gt le)
> (simplify
> (cmp @1 (trunc_mod @0 @1))
> Index: gcc/testsuite/gcc.dg/tree-ssa/andnot-1.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/tree-ssa/andnot-1.c (revision 0)
> +++ gcc/testsuite/gcc.dg/tree-ssa/andnot-1.c (working copy)
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O -fdump-tree-optimized-raw" } */
> +
> +unsigned f(unsigned i){
> + i >>= __SIZEOF_INT__ * __CHAR_BIT__ - 3;
> + i = ~i;
> + return i & 7;
> +}
> +
> +/* { dg-final { scan-tree-dump "bit_xor_expr" "optimized" } } */
> +/* { dg-final { scan-tree-dump-not "bit_not_expr" "optimized" } } */
> +/* { dg-final { scan-tree-dump-not "bit_and_expr" "optimized" } } */
> Index: gcc/testsuite/gcc.dg/tree-ssa/pr69270.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/tree-ssa/pr69270.c (revision 236194)
> +++ gcc/testsuite/gcc.dg/tree-ssa/pr69270.c (working copy)
> @@ -1,21 +1,19 @@
> /* { dg-do compile } */
> /* { dg-options "-O2 -fsplit-paths -fdump-tree-dom3-details" } */
>
> /* There should be two references to bufferstep that turn into
> constants. */
> /* { dg-final { scan-tree-dump-times "Replaced .bufferstep_\[0-9\]+. with
> constant .0." 1 "dom3"} } */
> /* { dg-final { scan-tree-dump-times "Replaced .bufferstep_\[0-9\]+. with
> constant .1." 1 "dom3"} } */
>
> /* And some assignments ought to fold down to constants. */
> -/* { dg-final { scan-tree-dump-times "Folded to: _\[0-9\]+ = -1;" 1 "dom3"}
> } */
> -/* { dg-final { scan-tree-dump-times "Folded to: _\[0-9\]+ = -2;" 1 "dom3"}
> } */
> /* { dg-final { scan-tree-dump-times "Folded to: _\[0-9\]+ = 1;" 1 "dom3"}
> } */
> /* { dg-final { scan-tree-dump-times "Folded to: _\[0-9\]+ = 0;" 1 "dom3"}
> } */
>
> /* The XOR operations should have been optimized to constants. */
> /* { dg-final { scan-tree-dump-not "bit_xor" "dom3"} } */
>
>
> extern int *stepsizeTable;
>
> void
>
