Rather than only consider -1 as a base, consider any negative number.
Cc: David Edelsohn <dje....@gmail.com>
---
* config/rs6000/rs6000.c (genimm_ppc::exam_search): Attempt to
mask negative numbers.
---
gcc/config/rs6000/rs6000.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index b27e476..9c08cca 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -8174,6 +8174,12 @@ genimm_ppc::exam_search (HOST_WIDE_INT c, int budget)
if (exam_mask (-1, c, sub_budget))
return true;
+ /* If the low 32-bits are negative, see if we can mask
+ those with RLDICL. */
+ test = ((c & 0xffffffffu) ^ 0x80000000u) - 0x80000000u;
+ if (test < 0 && exam_mask (test, c | 0xffffffffu, sub_budget))
+ return true;
+
/* If the two halves are equal, use an insert. */
if (c >> 32 == test && exam_sub (test, sub_budget))
{
--
2.4.3
