On Mon, Sep 9, 2024 at 3:11 PM Richard Biener <richard.guent...@gmail.com> wrote: > > On Thu, Aug 29, 2024 at 9:03 AM <konstantinos.elefther...@vrull.eu> wrote: > > > > From: kelefth <konstantinos.elefther...@vrull.eu> > > > > In expressions like (a != b || ((a ^ b) & c) == d) and > > (a != b || (a ^ b) == c), (a ^ b) is folded to false. > > In the equivalent expressions (((a ^ b) & c) == d || a != b) and > > ((a ^ b) == c || a != b) this is not happening. > > > > This patch adds the following simplifications in match.pd: > > ((a ^ b) & c) == d || a != b --> 0 == d || a != b > > (a ^ b) == c || a != b --> 0 == c || a != b > > > > PR tree-optimization/114326 > > > > gcc/ChangeLog: > > > > * match.pd: Add two patterns to fold a ^ b to 0, when a == b. > > > > gcc/testsuite/ChangeLog: > > > > * gcc.dg/tree-ssa/fold-xor-and-or.c: New test. > > * gcc.dg/tree-ssa/fold-xor-or.c: New test. > > > > Reviewed-by: Christoph Müllner <christoph.muell...@vrull.eu> > > Signed-off-by: Philipp Tomsich <philipp.toms...@vrull.eu> > > Signed-off-by: Konstantinos Eleftheriou <konstantinos.elefther...@vrull.eu> > > --- > > gcc/match.pd | 30 ++++++++++++++++++ > > .../gcc.dg/tree-ssa/fold-xor-and-or.c | 31 +++++++++++++++++++ > > gcc/testsuite/gcc.dg/tree-ssa/fold-xor-or.c | 31 +++++++++++++++++++ > > 3 files changed, 92 insertions(+) > > create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/fold-xor-and-or.c > > create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/fold-xor-or.c > > > > diff --git a/gcc/match.pd b/gcc/match.pd > > index be211535a49..6bab3cfbde1 100644 > > --- a/gcc/match.pd > > +++ b/gcc/match.pd > > @@ -10727,3 +10727,33 @@ and, > > } > > (if (full_perm_p) > > (vec_perm (op@3 @0 @1) @3 @2)))))) > >> Can you please place those patterns next to related ones? I suggest >> after (type)([0,1]@a != 0) -> (type)a and before >> /* We can't reassociate at all for saturating types. */
Yes, I will fix that. > > > > +/* ((a ^ b) & c) == d || a != b --> (0 == d || a != b). */ > >> The comment indicates == d but you also test for other >> comparison ops. As far as I can see your testcases also >> only cover ==. I will change "==" to "cmp" in the comments and add additional testcases. My intention is to cover all operations included in "simple_comparison". > > > > +(for cmp (simple_comparison) > > + (simplify > > + (bit_ior > > + (cmp > > + (bit_and > > This needs :c > > > + (bit_xor @0 @1) > > Likewise. Right, I will fix these cases. > > >> I think you also need :c on the comparison to match >> d == (...). In that case, I would need to handle non-commutative operations (e.g. >) separately, right? > > > > + tree_expr_nonzero_p@2) > > + @3) > > + (ne@4 @0 @1)) > > + (bit_ior > > + (cmp > > + { build_zero_cst (TREE_TYPE (@0)); } > > + @3) > > + @4))) > > + > > +/* (a ^ b) == c || a != b --> (0 == c || a != b). */ > > +(for cmp (simple_comparison) > > + (simplify > > + (bit_ior > > + (cmp > > + (bit_xor @0 @1) > > similar, :c here and also on the comparison. Same > question with regard to == c. > > > + @2) > > + (ne@3 @0 @1)) > > + (bit_ior > > + (cmp > > + { build_zero_cst (TREE_TYPE (@0)); } > > + @2) > > + @3))) > > \ No newline at end of file > > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/fold-xor-and-or.c > > b/gcc/testsuite/gcc.dg/tree-ssa/fold-xor-and-or.c > > new file mode 100644 > > index 00000000000..ec327e62f6e > > --- /dev/null > > +++ b/gcc/testsuite/gcc.dg/tree-ssa/fold-xor-and-or.c > > @@ -0,0 +1,31 @@ > > +/* { dg-do compile } */ > > +/* { dg-options "-O3 -fdump-tree-optimized" } */ > > + > > +int cmp1(int d1, int d2) { > > + if (((d1 ^ d2) & 0xabcd) == 0 || d1 != d2) > > + return 0; > > + return 1; > > +} > > + > > +int cmp2(int d1, int d2) { > > + if (d1 != d2 || ((d1 ^ d2) & 0xabcd) == 0) > > + return 0; > > + return 1; > > +} > > + > > +typedef unsigned long int uint64_t; > > + > > +int cmp1_64(uint64_t d1, uint64_t d2) { > > + if (((d1 ^ d2) & 0xabcd) == 0 || d1 != d2) > > + return 0; > > + return 1; > > +} > > + > > +int cmp2_64(uint64_t d1, uint64_t d2) { > > + if (d1 != d2 || ((d1 ^ d2) & 0xabcd) == 0) > > + return 0; > > + return 1; > > +} > > + > > +/* The if should be removed, so the condition should not exist */ > > +/* { dg-final { scan-tree-dump-not "d1_\[0-9\]+.D. \\^ d2_\[0-9\]+.D." > > "optimized" } } */ > > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/fold-xor-or.c > > b/gcc/testsuite/gcc.dg/tree-ssa/fold-xor-or.c > > new file mode 100644 > > index 00000000000..f5fce847394 > > --- /dev/null > > +++ b/gcc/testsuite/gcc.dg/tree-ssa/fold-xor-or.c > > @@ -0,0 +1,31 @@ > > +/* { dg-do compile } */ > > +/* { dg-options "-O3 -fdump-tree-optimized" } */ > > + > > +int cmp1(int d1, int d2) { > > + if ((d1 ^ d2) == 0xabcd || d1 != d2) > > + return 0; > > + return 1; > > +} > > + > > +int cmp2(int d1, int d2) { > > + if (d1 != d2 || (d1 ^ d2) == 0xabcd) > > + return 0; > > + return 1; > > +} > > + > > +typedef unsigned long int uint64_t; > > + > > +int cmp1_64(uint64_t d1, uint64_t d2) { > > + if ((d1 ^ d2) == 0xabcd || d1 != d2) > > + return 0; > > + return 1; > > +} > > + > > +int cmp2_64(uint64_t d1, uint64_t d2) { > > + if (d1 != d2 || (d1 ^ d2) == 0xabcd) > > + return 0; > > + return 1; > > +} > > + > > +/* The if should be removed, so the condition should not exist */ > > +/* { dg-final { scan-tree-dump-not "d1_\[0-9\]+.D. \\^ d2_\[0-9\]+.D." > > "optimized" } } */ > > -- > > 2.46.0 > > Thanks for the feedback, Konstantinos