configurator: Fix CTZ detection
authorRasmus Villemoes <rv@rasmusvillemoes.dk>
Tue, 7 Oct 2014 20:19:41 +0000 (22:19 +0200)
committerRusty Russell <rusty@rustcorp.com.au>
Mon, 13 Oct 2014 05:59:34 +0000 (16:29 +1030)
The literal "1" in "1 << (sizeof(long{, long})*8 - 1)" should be 1L or
1LL, so that the expression has the right type. Otherwise, the shift
is only by 31 bits on x86 (other platforms may behave differently). To
avoid language lawyers shouting UB at me, and since
__builtin_ctz{,l,ll} formally takes unsigned parameters, use UL and
ULL suffixes.

Also, fix a typo (missing parenthesis) in the code for CTZLL causing
the detection of __builtin_ctzll to always fail for the wrong reason.

Signed-off-by: Rasmus Villemoes <rv@rasmusvillemoes.dk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
tools/configurator/configurator.c

index d1aa5c61a564670e915a6921ee06fd9ec0968817..51ac8fbfeba777577cb607d48518818f74aa9ed8 100644 (file)
@@ -117,9 +117,9 @@ static struct test tests[] = {
        { "HAVE_BUILTIN_CTZ", INSIDE_MAIN, NULL, NULL,
          "return __builtin_ctz(1 << (sizeof(int)*8 - 1)) == (sizeof(int)*8 - 1) ? 0 : 1;" },
        { "HAVE_BUILTIN_CTZL", INSIDE_MAIN, NULL, NULL,
-         "return __builtin_ctzl(1 << (sizeof(long)*8 - 1)) == (sizeof(long)*8 - 1) ? 0 : 1;" },
+         "return __builtin_ctzl(1UL << (sizeof(long)*8 - 1)) == (sizeof(long)*8 - 1) ? 0 : 1;" },
        { "HAVE_BUILTIN_CTZLL", INSIDE_MAIN, NULL, NULL,
-         "return __builtin_ctzll(1 << (sizeof(long long)*8 - 1) == (sizeof(long long)*8 - 1) ? 0 : 1;" },
+         "return __builtin_ctzll(1ULL << (sizeof(long long)*8 - 1)) == (sizeof(long long)*8 - 1) ? 0 : 1;" },
        { "HAVE_BUILTIN_CONSTANT_P", INSIDE_MAIN, NULL, NULL,
          "return __builtin_constant_p(1) ? 0 : 1;" },
        { "HAVE_BUILTIN_EXPECT", INSIDE_MAIN, NULL, NULL,