[gcc r12-2137] PR tree-optimization/40210: Fold (bswap(X)>>C1)&C2 to (X>>C3)&C2 in match.pd

[gcc r12-2137] PR tree-optimization/40210: Fold (bswap(X)>>C1)&C2 to (X>>C3)&C2 in match.pd

[Roger Sayle]

https://gcc.gnu.org/g:4c619132b3f14dc5e672a7f2f0e09cb784193559

commit r12-2137-g4c619132b3f14dc5e672a7f2f0e09cb784193559
Author: Roger Sayle <roger@nextmovesoftware.com>
Date:   Thu Jul 8 11:46:14 2021 +0100

    PR tree-optimization/40210: Fold (bswap(X)>>C1)&C2 to (X>>C3)&C2 in match.pd
    
    All of the optimizations/transformations mentioned in bugzilla for
    PR tree-optimization/40210 are already implemented in mainline GCC,
    with one exception.  In comment #5, there's a suggestion that
    (bswap64(x)>>56)&0xff can be implemented without the bswap as
    (unsigned char)x, or equivalently x&0xff.
    
    This patch implements the above optimization, and closely related
    variants.  For any single bit, (bswap(X)>>C1)&1 can be simplified
    to (X>>C2)&1, where bit position C2 is the appropriate permutation
    of C1.  Similarly, the bswap can eliminated if the desired set of
    bits all lie within the same byte, hence (bswap(x)>>8)&255 can
    always be optimized, as can (bswap(x)>>8)&123.
    
    Previously,
    int foo(long long x) {
      return (__builtin_bswap64(x) >> 56) & 0xff;
    }
    
    compiled with -O2 to
    foo:    movq    %rdi, %rax
            bswap   %rax
            shrq    $56, %rax
            ret
    
    with this patch, it now compiles to
    foo:    movzbl  %dil, %eax
            ret
    
    2021-07-08  Roger Sayle  <roger@nextmovesoftware.com>
                Richard Biener  <rguenther@suse.de>
    
    gcc/ChangeLog
            PR tree-optimization/40210
            * match.pd (bswap optimizations): Simplify (bswap(x)>>C1)&C2 as
            (x>>C3)&C2 when possible.  Simplify bswap(x)>>C1 as ((T)x)>>C2
            when possible.  Simplify bswap(x)&C1 as (x>>C2)&C1 when 0<=C1<=255.
    
    gcc/testsuite/ChangeLog
            PR tree-optimization/40210
            * gcc.dg/builtin-bswap-13.c: New test.
            * gcc.dg/builtin-bswap-14.c: New test.

Diff:
---
 gcc/match.pd                            |  68 ++++++-
 gcc/testsuite/gcc.dg/builtin-bswap-13.c | 329 ++++++++++++++++++++++++++++++++
 gcc/testsuite/gcc.dg/builtin-bswap-14.c | 302 +++++++++++++++++++++++++++++
 3 files changed, 697 insertions(+), 2 deletions(-)

diff --git a/gcc/match.pd b/gcc/match.pd
index 72860fbd448..334e8cc0496 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3610,7 +3610,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   (complex (convert:itype @0) (negate (convert:itype @1)))))
 
 /* BSWAP simplifications, transforms checked by gcc.dg/builtin-bswap-8.c.  */
-(for bswap (BUILT_IN_BSWAP16 BUILT_IN_BSWAP32 BUILT_IN_BSWAP64)
+(for bswap (BUILT_IN_BSWAP16 BUILT_IN_BSWAP32
+	    BUILT_IN_BSWAP64 BUILT_IN_BSWAP128)
  (simplify
   (bswap (bswap @0))
   @0)
@@ -3620,7 +3621,70 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  (for bitop (bit_xor bit_ior bit_and)
   (simplify
    (bswap (bitop:c (bswap @0) @1))
-   (bitop @0 (bswap @1)))))
+   (bitop @0 (bswap @1))))
+ /* (bswap(x) >> C1) & C2 can sometimes be simplified to (x >> C3) & C2.  */
+ (simplify
+  (bit_and (convert1? (rshift@0 (convert2? (bswap@4 @1)) INTEGER_CST@2))
+	   INTEGER_CST@3)
+   (if (BITS_PER_UNIT == 8
+	&& tree_fits_uhwi_p (@2)
+	&& tree_fits_uhwi_p (@3))
+    (with
+     {
+      unsigned HOST_WIDE_INT prec = TYPE_PRECISION (TREE_TYPE (@4));
+      unsigned HOST_WIDE_INT bits = tree_to_uhwi (@2);
+      unsigned HOST_WIDE_INT mask = tree_to_uhwi (@3);
+      unsigned HOST_WIDE_INT lo = bits & 7;
+      unsigned HOST_WIDE_INT hi = bits - lo;
+     }
+     (if (bits < prec
+	  && mask < (256u>>lo)
+	  && bits < TYPE_PRECISION (TREE_TYPE(@0)))
+      (with { unsigned HOST_WIDE_INT ns = (prec - (hi + 8)) + lo; }
+       (if (ns == 0)
+	(bit_and (convert @1) @3)
+	(with
+	 {
+	  tree utype = unsigned_type_for (TREE_TYPE (@1));
+	  tree nst = build_int_cst (integer_type_node, ns);
+	 }
+	 (bit_and (convert (rshift:utype (convert:utype @1) {nst;})) @3))))))))
+ /* bswap(x) >> C1 can sometimes be simplified to (T)x >> C2.  */
+ (simplify
+  (rshift (convert? (bswap@2 @0)) INTEGER_CST@1)
+   (if (BITS_PER_UNIT == 8
+	&& CHAR_TYPE_SIZE == 8
+	&& tree_fits_uhwi_p (@1))
+    (with
+     {
+      unsigned HOST_WIDE_INT prec = TYPE_PRECISION (TREE_TYPE (@2));
+      unsigned HOST_WIDE_INT bits = tree_to_uhwi (@1);
+     }
+     (if (bits + 8 == prec)
+      (if (TYPE_UNSIGNED (type))
+       (convert (convert:unsigned_char_type_node @0))
+       (convert (convert:signed_char_type_node @0)))
+      (if (bits < prec && bits + 8 > prec)
+       (with 
+	{
+	 tree nst = build_int_cst (integer_type_node, bits & 7);
+	 tree bt = TYPE_UNSIGNED (type) ? unsigned_char_type_node
+					: signed_char_type_node;
+	}
+	(convert (rshift:bt (convert:bt @0) {nst;}))))))))
+ /* bswap(x) & C1 can sometimes be simplified to (x >> C2) & C1.  */
+ (simplify
+  (bit_and (convert? (bswap@2 @0)) INTEGER_CST@1)
+   (if (BITS_PER_UNIT == 8
+	&& tree_fits_uhwi_p (@1)
+	&& tree_to_uhwi (@1) < 256)
+    (with
+     {
+      unsigned HOST_WIDE_INT prec = TYPE_PRECISION (TREE_TYPE (@2));
+      tree utype = unsigned_type_for (TREE_TYPE (@0));
+      tree nst = build_int_cst (integer_type_node, prec - 8);
+     }
+     (bit_and (convert (rshift:utype (convert:utype @0) {nst;})) @1)))))
 
 
 /* Combine COND_EXPRs and VEC_COND_EXPRs.  */
diff --git a/gcc/testsuite/gcc.dg/builtin-bswap-13.c b/gcc/testsuite/gcc.dg/builtin-bswap-13.c
new file mode 100644
index 00000000000..6dc4c15b450
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/builtin-bswap-13.c
@@ -0,0 +1,329 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+int test_s32_0_1(int x) { return __builtin_bswap32(x) & 1; }
+int test_s32_0_2(int x) { return __builtin_bswap32(x) & 2; }
+int test_s32_0_240(int x) { return __builtin_bswap32(x) & 240; }
+int test_s32_0_255(int x) { return __builtin_bswap32(x) & 255; }
+int test_s32_1_1(int x) { return (__builtin_bswap32(x) >> 1) & 1; }
+int test_s32_7_1(int x) { return (__builtin_bswap32(x) >> 7) & 1; }
+int test_s32_8_1(int x) { return (__builtin_bswap32(x) >> 8) & 1; }
+int test_s32_8_240(int x) { return (__builtin_bswap32(x) >> 8) & 240; }
+int test_s32_8_255(int x) { return (__builtin_bswap32(x) >> 8) & 255; }
+int test_s32_15_1(int x) { return (__builtin_bswap32(x) >> 15) & 1; }
+int test_s32_16_1(int x) { return (__builtin_bswap32(x) >> 16) & 1; }
+int test_s32_16_240(int x) { return (__builtin_bswap32(x) >> 16) & 240; }
+int test_s32_16_255(int x) { return (__builtin_bswap32(x) >> 16) & 255; }
+int test_s32_24_1(int x) { return (__builtin_bswap32(x) >> 24) & 1; }
+int test_s32_24_240(int x) { return (__builtin_bswap32(x) >> 24) & 240; }
+int test_s32_24_255(int x) { return (__builtin_bswap32(x) >> 24) & 255; }
+int test_s32_31_1(int x) { return (__builtin_bswap32(x) >> 31) & 1; }
+
+int test_S32_0_1(int x) { return (int)__builtin_bswap32(x) & 1; }
+int test_S32_0_2(int x) { return (int)__builtin_bswap32(x) & 2; }
+int test_S32_0_240(int x) { return (int)__builtin_bswap32(x) & 240; }
+int test_S32_0_255(int x) { return (int)__builtin_bswap32(x) & 255; }
+int test_S32_1_1(int x) { return ((int)__builtin_bswap32(x) >> 1) & 1; }
+int test_S32_7_1(int x) { return ((int)__builtin_bswap32(x) >> 7) & 1; }
+int test_S32_8_1(int x) { return ((int)__builtin_bswap32(x) >> 8) & 1; }
+int test_S32_8_240(int x) { return ((int)__builtin_bswap32(x) >> 8) & 240; }
+int test_S32_8_255(int x) { return ((int)__builtin_bswap32(x) >> 8) & 255; }
+int test_S32_15_1(int x) { return ((int)__builtin_bswap32(x) >> 15) & 1; }
+int test_S32_16_1(int x) { return ((int)__builtin_bswap32(x) >> 16) & 1; }
+int test_S32_16_240(int x) { return ((int)__builtin_bswap32(x) >> 16) & 240; }
+int test_S32_16_255(int x) { return ((int)__builtin_bswap32(x) >> 16) & 255; }
+int test_S32_24_1(int x) { return ((int)__builtin_bswap32(x) >> 24) & 1; }
+int test_S32_24_240(int x) { return ((int)__builtin_bswap32(x) >> 24) & 240; }
+int test_S32_24_255(int x) { return ((int)__builtin_bswap32(x) >> 24) & 255; }
+int test_S32_31_1(int x) { return ((int)__builtin_bswap32(x) >> 31) & 1; }
+
+unsigned int test_u32_24_255(unsigned int x) {
+  return (__builtin_bswap32(x) >> 24) & 255;
+}
+
+long long test_s64_0_1(long long x) {
+  return __builtin_bswap64(x) & 1;
+}
+long long test_s64_0_2(long long x) {
+  return __builtin_bswap64(x) & 2;
+}
+long long test_s64_0_240(long long x) {
+  return __builtin_bswap64(x) & 240;
+}
+long long test_s64_0_255(long long x) {
+  return __builtin_bswap64(x) & 255;
+}
+long long test_s64_7_1(long long x) {
+  return (__builtin_bswap64(x) >> 7) & 1;
+}
+long long test_s64_8_1(long long x) {
+  return (__builtin_bswap64(x) >> 8) & 1;
+}
+long long test_s64_8_240(long long x) {
+  return (__builtin_bswap64(x) >> 56) & 240;
+}
+long long test_s64_8_255(long long x) {
+  return (__builtin_bswap64(x) >> 8) & 255;
+}
+long long test_s64_9_1(long long x) {
+  return (__builtin_bswap64(x) >> 9) & 1;
+}
+long long test_s64_31_1(long long x) {
+  return (__builtin_bswap64(x) >> 31) & 1;
+}
+long long test_s64_32_1(long long x) {
+  return (__builtin_bswap64(x) >> 32) & 1;
+}
+long long test_s64_32_240(long long x) {
+  return (__builtin_bswap64(x) >> 32) & 240;
+}
+long long test_s64_32_255(long long x) {
+  return (__builtin_bswap64(x) >> 32) & 255;
+}
+long long test_s64_33_1(long long x) {
+  return (__builtin_bswap64(x) >> 33) & 1;
+}
+long long test_s64_48_1(long long x) {
+  return (__builtin_bswap64(x) >> 48) & 1;
+}
+long long test_s64_48_240(long long x) {
+  return (__builtin_bswap64(x) >> 48) & 240;
+}
+long long test_s64_48_255(long long x) {
+  return (__builtin_bswap64(x) >> 48) & 255;
+}
+long long test_s64_56_1(long long x) {
+  return (__builtin_bswap64(x) >> 56) & 1;
+}
+long long test_s64_56_240(long long x) {
+  return (__builtin_bswap64(x) >> 56) & 240;
+}
+long long test_s64_56_255(long long x) {
+  return (__builtin_bswap64(x) >> 56) & 255;
+}
+long long test_s64_57_1(long long x) {
+  return (__builtin_bswap64(x) >> 57) & 1;
+}
+long long test_s64_63_1(long long x) {
+  return (__builtin_bswap64(x) >> 63) & 1;
+}
+
+long long test_S64_0_1(long long x) {
+  return (long long)__builtin_bswap64(x) & 1;
+}
+long long test_S64_0_2(long long x) {
+  return (long long)__builtin_bswap64(x) & 2;
+}
+long long test_S64_0_240(long long x) {
+  return (long long)__builtin_bswap64(x) & 240;
+}
+long long test_S64_0_255(long long x) {
+  return (long long)__builtin_bswap64(x) & 255;
+}
+long long test_S64_7_1(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 7) & 1;
+}
+long long test_S64_8_1(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 8) & 1;
+}
+long long test_S64_8_240(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 56) & 240;
+}
+long long test_S64_8_255(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 8) & 255;
+}
+long long test_S64_9_1(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 9) & 1;
+}
+long long test_S64_31_1(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 31) & 1;
+}
+long long test_S64_32_1(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 32) & 1;
+}
+long long test_S64_32_240(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 32) & 240;
+}
+long long test_S64_32_255(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 32) & 255;
+}
+long long test_S64_33_1(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 33) & 1;
+}
+long long test_S64_48_1(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 48) & 1;
+}
+long long test_S64_48_240(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 48) & 240;
+}
+long long test_S64_48_255(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 48) & 255;
+}
+long long test_S64_56_1(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 56) & 1;
+}
+long long test_S64_56_240(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 56) & 240;
+}
+long long test_S64_56_255(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 56) & 255;
+}
+long long test_S64_57_1(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 57) & 1;
+}
+long long test_S64_63_1(long long x) {
+  return ((long long)__builtin_bswap64(x) >> 63) & 1;
+}
+
+unsigned long long test_u64_56_255(unsigned long long x) {
+  return (__builtin_bswap64(x) >> 56) & 255;
+}
+
+short test_s16_0_1(short x) {
+  return __builtin_bswap16(x) & 1;
+}
+short test_s16_0_240(short x) {
+  return __builtin_bswap16(x) & 240;
+}
+short test_s16_0_255(short x) {
+  return __builtin_bswap16(x) & 255;
+}
+short test_s16_1_1(short x) {
+  return (__builtin_bswap16(x) >> 1) & 1;
+}
+short test_s16_7_1(short x) {
+  return (__builtin_bswap16(x) >> 7) & 1;
+}
+short test_s16_8_1(short x) {
+  return (__builtin_bswap16(x) >> 8) & 1;
+}
+short test_s16_8_240(short x) {
+  return (__builtin_bswap16(x) >> 8) & 240;
+}
+short test_s16_8_255(short x) {
+  return (__builtin_bswap16(x) >> 8) & 255;
+}
+short test_s16_9_1(short x) {
+  return (__builtin_bswap16(x) >> 9) & 1;
+}
+short test_s16_15_1(short x) {
+  return (__builtin_bswap16(x) >> 15) & 1;
+}
+
+short test_S16_0_1(short x) {
+  return (short)__builtin_bswap16(x) & 1;
+}
+short test_S16_0_240(short x) {
+  return (short)__builtin_bswap16(x) & 240;
+}
+short test_S16_0_255(short x) {
+  return (short)__builtin_bswap16(x) & 255;
+}
+short test_S16_1_1(short x) {
+  return ((short)__builtin_bswap16(x) >> 1) & 1;
+}
+short test_S16_7_1(short x) {
+  return ((short)__builtin_bswap16(x) >> 7) & 1;
+}
+short test_S16_8_1(short x) {
+  return ((short)__builtin_bswap16(x) >> 8) & 1;
+}
+short test_S16_8_240(short x) {
+  return ((short)__builtin_bswap16(x) >> 8) & 240;
+}
+short test_S16_8_255(short x) {
+  return ((short)__builtin_bswap16(x) >> 8) & 255;
+}
+short test_S16_9_1(short x) {
+  return ((short)__builtin_bswap16(x) >> 9) & 1;
+}
+short test_S16_15_1(short x) {
+  return ((short)__builtin_bswap16(x) >> 15) & 1;
+}
+
+unsigned short test_u16_8_255(unsigned short x) {
+  return (__builtin_bswap16(x) >> 8) & 255;
+}
+
+
+/* Shifts only */
+int test_s32_24(int x) {
+  return __builtin_bswap32(x) >> 24;
+}
+int test_s32_25(int x) {
+  return __builtin_bswap32(x) >> 25;
+}
+int test_s32_30(int x) {
+  return __builtin_bswap32(x) >> 30;
+}
+int test_s32_31(int x) {
+  return __builtin_bswap32(x) >> 31;
+}
+
+unsigned int test_u32_24(unsigned int x) {
+ return __builtin_bswap32(x) >> 24;
+}
+unsigned int test_u32_25(unsigned int x) {
+ return __builtin_bswap32(x) >> 25;
+}
+unsigned int test_u32_30(unsigned int x) {
+ return __builtin_bswap32(x) >> 30;
+}
+unsigned int test_u32_31(unsigned int x) {
+ return __builtin_bswap32(x) >> 31;
+}
+
+long long test_s64_56(long long x) {
+  return __builtin_bswap64(x) >> 56;
+}
+long long test_s64_57(long long x) {
+  return __builtin_bswap64(x) >> 57;
+}
+long long test_s64_62(long long x) {
+  return __builtin_bswap64(x) >> 62;
+}
+long long test_s64_63(long long x) {
+  return __builtin_bswap64(x) >> 63;
+}
+
+unsigned long long test_u64_56(unsigned long long x) {
+  return __builtin_bswap64(x) >> 56;
+}
+unsigned long long test_u64_57(unsigned long long x) {
+  return __builtin_bswap64(x) >> 57;
+}
+unsigned long long test_u64_62(unsigned long long x) {
+  return __builtin_bswap64(x) >> 62;
+}
+unsigned long long test_u64_63(unsigned long long x) {
+  return __builtin_bswap64(x) >> 63;
+}
+
+short test_s16_8(short x) {
+  return __builtin_bswap16(x) >> 8;
+}
+short test_s16_9(short x) {
+  return __builtin_bswap16(x) >> 9;
+}
+short test_s16_14(short x) {
+  return __builtin_bswap16(x) >> 14;
+}
+short test_s16_15(short x) {
+  return __builtin_bswap16(x) >> 15;
+}
+
+unsigned short test_u16_8(unsigned short x) {
+  return __builtin_bswap16(x) >> 8;
+}
+unsigned short test_u16_9(unsigned short x) {
+  return __builtin_bswap16(x) >> 9;
+}
+unsigned short test_u16_14(unsigned short x) {
+  return __builtin_bswap16(x) >> 14;
+}
+unsigned short test_u16_15(unsigned short x) {
+  return __builtin_bswap16(x) >> 15;
+}
+
+/* { dg-final { scan-tree-dump-not "__builtin_bswap" "optimized" } } */
+
diff --git a/gcc/testsuite/gcc.dg/builtin-bswap-14.c b/gcc/testsuite/gcc.dg/builtin-bswap-14.c
new file mode 100644
index 00000000000..62711d8ef64
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/builtin-bswap-14.c
@@ -0,0 +1,302 @@
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+extern void abort (void);
+
+
+__attribute__ ((noinline, noclone))
+static int rt32 (int x, int y, int z) {
+  return (__builtin_bswap32(x) >> y) & z;
+}
+#define TEST32(X,Y,Z) if(((__builtin_bswap32(X)>>Y)&Z)!=rt32(X,Y,Z)) abort()
+void test32(int x)
+{
+  TEST32(x,0,1);
+  TEST32(x,0,255);
+  TEST32(x,1,1);
+  TEST32(x,2,1);
+  TEST32(x,3,1);
+  TEST32(x,4,1);
+  TEST32(x,5,1);
+  TEST32(x,6,1);
+  TEST32(x,7,1);
+  TEST32(x,8,1);
+  TEST32(x,8,255);
+  TEST32(x,9,1);
+  TEST32(x,10,1);
+  TEST32(x,11,1);
+  TEST32(x,12,1);
+  TEST32(x,13,1);
+  TEST32(x,14,1);
+  TEST32(x,15,1);
+  TEST32(x,16,1);
+  TEST32(x,16,255);
+  TEST32(x,17,1);
+  TEST32(x,18,1);
+  TEST32(x,19,1);
+  TEST32(x,20,1);
+  TEST32(x,21,1);
+  TEST32(x,22,1);
+  TEST32(x,23,1);
+  TEST32(x,24,1);
+  TEST32(x,24,255);
+  TEST32(x,25,1);
+  TEST32(x,26,1);
+  TEST32(x,27,1);
+  TEST32(x,28,1);
+  TEST32(x,29,1);
+  TEST32(x,30,1);
+  TEST32(x,31,1);
+}
+
+#if __SIZEOF_LONG_LONG__ == 8
+__attribute__ ((noinline, noclone))
+static long long rt64 (long long x, int y, long long z) {
+  return (__builtin_bswap64(x) >> y) & z;
+}
+#define TEST64(X,Y,Z) if(((__builtin_bswap64(X)>>Y)&Z)!=rt64(X,Y,Z)) abort()
+void test64(long long x)
+{
+  TEST64(x,0,1);
+  TEST64(x,0,255);
+  TEST64(x,1,1);
+  TEST64(x,2,1);
+  TEST64(x,3,1);
+  TEST64(x,4,1);
+  TEST64(x,5,1);
+  TEST64(x,6,1);
+  TEST64(x,7,1);
+  TEST64(x,8,1);
+  TEST64(x,8,255);
+  TEST64(x,9,1);
+  TEST64(x,10,1);
+  TEST64(x,11,1);
+  TEST64(x,12,1);
+  TEST64(x,13,1);
+  TEST64(x,14,1);
+  TEST64(x,15,1);
+  TEST64(x,16,1);
+  TEST64(x,16,255);
+  TEST64(x,17,1);
+  TEST64(x,18,1);
+  TEST64(x,19,1);
+  TEST64(x,20,1);
+  TEST64(x,21,1);
+  TEST64(x,22,1);
+  TEST64(x,23,1);
+  TEST64(x,24,1);
+  TEST64(x,24,255);
+  TEST64(x,25,1);
+  TEST64(x,26,1);
+  TEST64(x,27,1);
+  TEST64(x,28,1);
+  TEST64(x,29,1);
+  TEST64(x,30,1);
+  TEST64(x,31,1);
+  TEST64(x,32,1);
+  TEST64(x,32,255);
+  TEST64(x,33,1);
+  TEST64(x,34,1);
+  TEST64(x,35,1);
+  TEST64(x,36,1);
+  TEST64(x,37,1);
+  TEST64(x,38,1);
+  TEST64(x,39,1);
+  TEST64(x,40,1);
+  TEST64(x,40,255);
+  TEST64(x,41,1);
+  TEST64(x,42,1);
+  TEST64(x,43,1);
+  TEST64(x,44,1);
+  TEST64(x,45,1);
+  TEST64(x,46,1);
+  TEST64(x,47,1);
+  TEST64(x,48,1);
+  TEST64(x,48,255);
+  TEST64(x,49,1);
+  TEST64(x,50,1);
+  TEST64(x,51,1);
+  TEST64(x,52,1);
+  TEST64(x,53,1);
+  TEST64(x,54,1);
+  TEST64(x,55,1);
+  TEST64(x,56,1);
+  TEST64(x,56,255);
+  TEST64(x,57,1);
+  TEST64(x,58,1);
+  TEST64(x,59,1);
+  TEST64(x,60,1);
+  TEST64(x,61,1);
+  TEST64(x,62,1);
+  TEST64(x,63,1);
+}
+#endif
+
+__attribute__ ((noinline, noclone))
+static int rt16 (int x, int y, int z) {
+  return (__builtin_bswap16(x) >> y) & z;
+}
+#define TEST16(X,Y,Z) if(((__builtin_bswap16(X)>>Y)&Z)!=rt16(X,Y,Z)) abort()
+void test16(int x)
+{
+  TEST16(x,0,1);
+  TEST16(x,0,255);
+  TEST16(x,1,1);
+  TEST16(x,2,1);
+  TEST16(x,3,1);
+  TEST16(x,4,1);
+  TEST16(x,5,1);
+  TEST16(x,6,1);
+  TEST16(x,7,1);
+  TEST16(x,8,1);
+  TEST16(x,8,255);
+  TEST16(x,9,1);
+  TEST16(x,10,1);
+  TEST16(x,11,1);
+  TEST16(x,12,1);
+  TEST16(x,13,1);
+  TEST16(x,14,1);
+  TEST16(x,15,1);
+}
+
+int main()
+{
+  test32(0x00000000);
+  test32(0xffffffff);
+  test32(0x00000001);
+  test32(0x00000002);
+  test32(0x00000004);
+  test32(0x00000008);
+  test32(0x00000010);
+  test32(0x00000020);
+  test32(0x00000040);
+  test32(0x00000080);
+  test32(0x00000100);
+  test32(0x00000200);
+  test32(0x00000400);
+  test32(0x00000800);
+  test32(0x00001000);
+  test32(0x00002000);
+  test32(0x00004000);
+  test32(0x00008000);
+  test32(0x00010000);
+  test32(0x00020000);
+  test32(0x00040000);
+  test32(0x00080000);
+  test32(0x00100000);
+  test32(0x00200000);
+  test32(0x00400000);
+  test32(0x00800000);
+  test32(0x01000000);
+  test32(0x02000000);
+  test32(0x04000000);
+  test32(0x08000000);
+  test32(0x10000000);
+  test32(0x20000000);
+  test32(0x40000000);
+  test32(0x80000000);
+  test32(0x12345678);
+  test32(0x87654321);
+  test32(0xdeadbeef);
+  test32(0xcafebabe);
+
+#if __SIZEOF_LONG_LONG__ == 8
+  test64(0x0000000000000000ll);
+  test64(0xffffffffffffffffll);
+  test64(0x0000000000000001ll);
+  test64(0x0000000000000002ll);
+  test64(0x0000000000000004ll);
+  test64(0x0000000000000008ll);
+  test64(0x0000000000000010ll);
+  test64(0x0000000000000020ll);
+  test64(0x0000000000000040ll);
+  test64(0x0000000000000080ll);
+  test64(0x0000000000000100ll);
+  test64(0x0000000000000200ll);
+  test64(0x0000000000000400ll);
+  test64(0x0000000000000800ll);
+  test64(0x0000000000001000ll);
+  test64(0x0000000000002000ll);
+  test64(0x0000000000004000ll);
+  test64(0x0000000000008000ll);
+  test64(0x0000000000010000ll);
+  test64(0x0000000000020000ll);
+  test64(0x0000000000040000ll);
+  test64(0x0000000000080000ll);
+  test64(0x0000000000100000ll);
+  test64(0x0000000000200000ll);
+  test64(0x0000000000400000ll);
+  test64(0x0000000000800000ll);
+  test64(0x0000000001000000ll);
+  test64(0x0000000002000000ll);
+  test64(0x0000000004000000ll);
+  test64(0x0000000008000000ll);
+  test64(0x0000000010000000ll);
+  test64(0x0000000020000000ll);
+  test64(0x0000000040000000ll);
+  test64(0x0000000080000000ll);
+  test64(0x0000000100000000ll);
+  test64(0x0000000200000000ll);
+  test64(0x0000000400000000ll);
+  test64(0x0000000800000000ll);
+  test64(0x0000001000000000ll);
+  test64(0x0000002000000000ll);
+  test64(0x0000004000000000ll);
+  test64(0x0000008000000000ll);
+  test64(0x0000010000000000ll);
+  test64(0x0000020000000000ll);
+  test64(0x0000040000000000ll);
+  test64(0x0000080000000000ll);
+  test64(0x0000100000000000ll);
+  test64(0x0000200000000000ll);
+  test64(0x0000400000000000ll);
+  test64(0x0000800000000000ll);
+  test64(0x0001000000000000ll);
+  test64(0x0002000000000000ll);
+  test64(0x0004000000000000ll);
+  test64(0x0008000000000000ll);
+  test64(0x0010000000000000ll);
+  test64(0x0020000000000000ll);
+  test64(0x0040000000000000ll);
+  test64(0x0080000000000000ll);
+  test64(0x0100000000000000ll);
+  test64(0x0200000000000000ll);
+  test64(0x0400000000000000ll);
+  test64(0x0800000000000000ll);
+  test64(0x1000000000000000ll);
+  test64(0x2000000000000000ll);
+  test64(0x4000000000000000ll);
+  test64(0x8000000000000000ll);
+  test64(0x0123456789abcdefll);
+  test64(0xfedcba9876543210ll);
+  test64(0xdeadbeefdeadbeefll);
+  test64(0xcafebabecafebabell);
+#endif
+
+  test16(0x0000);
+  test16(0xffff);
+  test16(0x0001);
+  test16(0x0002);
+  test16(0x0004);
+  test16(0x0008);
+  test16(0x0010);
+  test16(0x0020);
+  test16(0x0040);
+  test16(0x0080);
+  test16(0x0100);
+  test16(0x0200);
+  test16(0x0400);
+  test16(0x0800);
+  test16(0x1000);
+  test16(0x2000);
+  test16(0x4000);
+  test16(0x8000);
+  test16(0x1234);
+  test16(0x4321);
+  test16(0xdead);
+  test16(0xbeef);
+  test16(0xcafe);
+  test16(0xbabe);
+
+  return 0;
+}