The following adjusts the tree.def documentation about VEC_PERM_EXPR
which wasn't adjusted when the restrictions of permutes with constant
mask were relaxed.
OK?
Thanks,
Richard.
PR middle-end/110541
* tree.def (VEC_PERM_EXPR): Adjust documentation to reflect
reality.
---
gcc/tree.def | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/gcc/tree.def b/gcc/tree.def
index 1fc2ca7a724..9e1a54ac2f9 100644
--- a/gcc/tree.def
+++ b/gcc/tree.def
@@ -565,13 +565,20 @@ DEFTREECODE (VEC_COND_EXPR, "vec_cond_expr",
tcc_expression, 3)
N = length(mask)
foreach i in N:
- M = mask[i] % (2*N)
- A = M < N ? v0[M] : v1[M-N]
+ M = mask[i] % (length(v0) + length(v1))
+ A[i] = M < length(v0) ? v0[M] : v1[M - length(v0)]
- V0 and V1 are vectors of the same type. MASK is an integer-typed
- vector. The number of MASK elements must be the same with the
- number of elements in V0 and V1. The size of the inner type
- of the MASK and of the V0 and V1 must be the same.
+ V0 and V1 are vectors of the same type.
+
+ When MASK is not constant:
+ MASK is an integer-typed vector. The number of MASK elements must
+ be the same with the number of elements in V0 and V1. The size of
+ the inner type of the MASK and of the V0 and V1 must be the same.
+
+ When MASK is constant:
+ MASK is an integer-typed vector. MASK elements outside of
+ [0, length(V0) + length(V1) - 1] invoke undefined behavior (the
+ modulo operation above doesn't apply).
*/
DEFTREECODE (VEC_PERM_EXPR, "vec_perm_expr", tcc_expression, 3)
--
2.35.3
