gcc/gcc6-pr69546.patch
2016-01-29 21:59:00 +01:00

70 lines
1.8 KiB
Diff

2016-01-29 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/69546
* wide-int.cc (wi::divmod_internal): For unsigned division
where both operands fit into uhwi, if o1 is 1 and o0 has
msb set, if divident_prec is larger than bits per hwi,
clear another quotient word and return 2 instead of 1.
* gcc.dg/torture/pr69546.c: New test.
--- gcc/wide-int.cc.jj 2016-01-26 11:46:39.000000000 +0100
+++ gcc/wide-int.cc 2016-01-29 11:59:33.348852003 +0100
@@ -1788,15 +1788,25 @@ wi::divmod_internal (HOST_WIDE_INT *quot
{
unsigned HOST_WIDE_INT o0 = dividend.to_uhwi ();
unsigned HOST_WIDE_INT o1 = divisor.to_uhwi ();
+ unsigned int quotient_len = 1;
if (quotient)
- quotient[0] = o0 / o1;
+ {
+ quotient[0] = o0 / o1;
+ if (o1 == 1
+ && (HOST_WIDE_INT) o0 < 0
+ && dividend_prec > HOST_BITS_PER_WIDE_INT)
+ {
+ quotient[1] = 0;
+ quotient_len = 2;
+ }
+ }
if (remainder)
{
remainder[0] = o0 % o1;
*remainder_len = 1;
}
- return 1;
+ return quotient_len;
}
/* Make the divisor and dividend positive and remember what we
--- gcc/testsuite/gcc.dg/torture/pr69546.c.jj 2016-01-29 12:06:03.148516651 +0100
+++ gcc/testsuite/gcc.dg/torture/pr69546.c 2016-01-29 12:08:17.847672967 +0100
@@ -0,0 +1,26 @@
+/* PR tree-optimization/69546 */
+/* { dg-do run { target int128 } } */
+
+unsigned __int128 __attribute__ ((noinline, noclone))
+foo (unsigned long long x)
+{
+ unsigned __int128 y = ~0ULL;
+ x >>= 63;
+ return y / (x | 1);
+}
+
+unsigned __int128 __attribute__ ((noinline, noclone))
+bar (unsigned long long x)
+{
+ unsigned __int128 y = ~33ULL;
+ x >>= 63;
+ return y / (x | 1);
+}
+
+int
+main ()
+{
+ if (foo (1) != ~0ULL || bar (17) != ~33ULL)
+ __builtin_abort ();
+ return 0;
+}