On Sun, Feb 24, 2019 at 03:12:38PM +0100, Richard Biener wrote:
> On February 24, 2019 12:58:05 PM GMT+01:00, Jakub Jelinek <ja...@redhat.com>
> wrote:
> >Hi!
> >
> >These builtins are perfect candidates for bitwise ccp, the bytes are
> >preserved, just byte-swapped.
> >
> >Noticed this while wondering why we haven't optimized the f9 function
> >in another PR, bswap64 zero extended from 32-bits, later casted to
> >32-bit
> >unsigned int is 0.
> >
> >Bootstrapped/regtested on x86_64-linux and i686-linux, ok for GCC10?
>
> OK.
Rebootstrapped/regtested now and committed to trunk. Thanks.
> >2019-02-23 Jakub Jelinek <ja...@redhat.com>
> >
> > PR tree-optimization/89475
> > * tree-ssa-ccp.c (evaluate_stmt): Handle BUILT_IN_BSWAP{16,32,64}
> > calls.
> >
> > * gcc.dg/tree-ssa/pr89475.c: New test.
> >
> >--- gcc/tree-ssa-ccp.c.jj 2019-01-01 12:37:17.078976247 +0100
> >+++ gcc/tree-ssa-ccp.c 2019-02-23 22:35:23.888343273 +0100
> >@@ -1960,6 +1960,35 @@ evaluate_stmt (gimple *stmt)
> > break;
> > }
> >
> >+ case BUILT_IN_BSWAP16:
> >+ case BUILT_IN_BSWAP32:
> >+ case BUILT_IN_BSWAP64:
> >+ val = get_value_for_expr (gimple_call_arg (stmt, 0), true);
> >+ if (val.lattice_val == UNDEFINED)
> >+ break;
> >+ else if (val.lattice_val == CONSTANT
> >+ && val.value
> >+ && TREE_CODE (val.value) == INTEGER_CST)
> >+ {
> >+ tree type = TREE_TYPE (gimple_call_lhs (stmt));
> >+ int prec = TYPE_PRECISION (type);
> >+ wide_int wval = wi::to_wide (val.value);
> >+ val.value
> >+ = wide_int_to_tree (type,
> >+ wide_int::from (wval, prec,
> >+ UNSIGNED).bswap ());
> >+ val.mask
> >+ = widest_int::from (wide_int::from (val.mask, prec,
> >+ UNSIGNED).bswap (),
> >+ UNSIGNED);
> >+ if (wi::sext (val.mask, prec) != -1)
> >+ break;
> >+ }
> >+ val.lattice_val = VARYING;
> >+ val.value = NULL_TREE;
> >+ val.mask = -1;
> >+ break;
> >+
> > default:;
> > }
> > }
> >--- gcc/testsuite/gcc.dg/tree-ssa/pr89475.c.jj 2019-02-23
> >18:58:23.035845645 +0100
> >+++ gcc/testsuite/gcc.dg/tree-ssa/pr89475.c 2019-02-23
> >18:59:38.462607598 +0100
> >@@ -0,0 +1,104 @@
> >+/* PR tree-optimization/89475 */
> >+/* { dg-do compile { target { ilp32 || lp64 } } } */
> >+/* { dg-options "-O2 -fdump-tree-optimized" } */
> >+/* { dg-final { scan-tree-dump-not "link_error " "optimized" } } */
> >+
> >+void link_error (void);
> >+
> >+unsigned short
> >+f0 (unsigned short x)
> >+{
> >+ x &= 0xaa55;
> >+ x = __builtin_bswap16 (x);
> >+ if (x & 0xaa55)
> >+ link_error ();
> >+ return x;
> >+}
> >+
> >+unsigned short
> >+f1 (unsigned short x)
> >+{
> >+ x &= 0x55aa;
> >+ x = __builtin_bswap16 (x);
> >+ if (x & 0x55aa)
> >+ link_error ();
> >+ return x;
> >+}
> >+
> >+unsigned int
> >+f2 (unsigned int x)
> >+{
> >+ x &= 0x55aa5aa5U;
> >+ x = __builtin_bswap32 (x);
> >+ if (x & 0x5aa555aaU)
> >+ link_error ();
> >+ return x;
> >+}
> >+
> >+unsigned long long int
> >+f3 (unsigned long long int x)
> >+{
> >+ x &= 0x55aa5aa544cc2211ULL;
> >+ x = __builtin_bswap64 (x);
> >+ if (x & 0xeedd33bb5aa555aaULL)
> >+ link_error ();
> >+ return x;
> >+}
> >+
> >+unsigned short
> >+f4 (unsigned short x)
> >+{
> >+ x = __builtin_bswap32 (x);
> >+ if (x != 0)
> >+ link_error ();
> >+ return x;
> >+}
> >+
> >+unsigned int
> >+f5 (unsigned int x)
> >+{
> >+ x = __builtin_bswap64 (x);
> >+ if (x != 0)
> >+ link_error ();
> >+ return x;
> >+}
> >+
> >+unsigned short
> >+f6 (unsigned short x)
> >+{
> >+ x |= 0xaa55;
> >+ x = __builtin_bswap16 (x);
> >+ if ((x | 0xaa55) != 0xffff)
> >+ link_error ();
> >+ return x;
> >+}
> >+
> >+unsigned short
> >+f7 (unsigned short x)
> >+{
> >+ x |= 0x55aa;
> >+ x = __builtin_bswap16 (x);
> >+ if ((x | 0x55aa) != 0xffff)
> >+ link_error ();
> >+ return x;
> >+}
> >+
> >+unsigned int
> >+f8 (unsigned int x)
> >+{
> >+ x |= 0x55aa5aa5U;
> >+ x = __builtin_bswap32 (x);
> >+ if ((x | 0x5aa555aaU) != 0xffffffffU)
> >+ link_error ();
> >+ return x;
> >+}
> >+
> >+unsigned long long int
> >+f9 (unsigned long long int x)
> >+{
> >+ x |= 0x55aa5aa544cc2211ULL;
> >+ x = __builtin_bswap64 (x);
> >+ if ((x | 0xeedd33bb5aa555aaULL) != 0xffffffffffffffffULL)
> >+ link_error ();
> >+ return x;
> >+}
Jakub
