In the MVE shift-and-insert insns, we special case VSLI by 0
and VSRI by <dt>, both of which mean "no shift". However we
incorrectly implemented these as "don't update the destination",
which works only if Qd == Qm. When Qd != Qm this kind of
shift must update Qd, honouring the predicate mask.
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
---
target/arm/mve_helper.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/target/arm/mve_helper.c b/target/arm/mve_helper.c
index db5d6220854..16a701933b8 100644
--- a/target/arm/mve_helper.c
+++ b/target/arm/mve_helper.c
@@ -1276,19 +1276,23 @@ DO_2SHIFT_S(vrshli_s, DO_VRSHLS)
void *vm, uint32_t shift) \
{ \
uint64_t *d = vd, *m = vm; \
- uint16_t mask; \
+ uint16_t mask = mve_element_mask(env); \
uint64_t shiftmask; \
unsigned e; \
if (shift == 0 || shift == ESIZE * 8) { \
/* \
* Only VSLI can shift by 0; only VSRI can shift by <dt>. \
* The generic logic would give the right answer for 0 but \
- * fails for <dt>. \
+ * fails for <dt>. In both cases, we must not shift the \
+ * input but just copy it to the destination, honouring \
+ * the predicate mask. \
*/ \
+ for (e = 0; e < 16 / 8; e++, mask >>= 8) { \
+ mergemask(&d[H8(e)], m[H8(e)], mask); \
+ } \
goto done; \
} \
assert(shift < ESIZE * 8); \
- mask = mve_element_mask(env); \
/* ESIZE / 2 gives the MO_* value if ESIZE is in [1,2,4] */ \
shiftmask = dup_const(ESIZE / 2, MASKFN(ESIZE * 8, shift)); \
for (e = 0; e < 16 / 8; e++, mask >>= 8) { \
--
2.20.1
