On 23/02/2024 13:02, Jakub Jelinek wrote:
On Fri, Feb 23, 2024 at 12:58:53PM +0000, Andrew Stubbs wrote:
This is a follow-up to the previous patch to ensure that integer vector
bit-masks do not have excess bits set. It fixes a bug, observed on
amdgcn, in which the mask could be incorrectly set to zero, resulting in
wrong-code.
The mask was broken when nunits==32. The patched version will probably
be broken for nunits==64, but I don't think any current targets have
masks with more than 64 bits.
OK for mainline?
Andrew
gcc/ChangeLog:
* expr.cc (store_constructor): Use 64-bit shifts.
No, this isn't 64-bit shift on all hosts.
Use HOST_WIDE_INT_1U instead.
OK, I did wonder if there was a proper way to do it. :)
How about this?
Andrew
vect: Fix integer overflow calculating mask
The mask was broken when nunits==32 on hosts where int is 32-bit.
gcc/ChangeLog:
* expr.cc (store_constructor): Use 64-bit shifts.
diff --git a/gcc/expr.cc b/gcc/expr.cc
index e238811110e..6bd16ac7f49 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -7879,8 +7879,8 @@ store_constructor (tree exp, rtx target, int cleared,
poly_int64 size,
auto nunits = TYPE_VECTOR_SUBPARTS (type).to_constant ();
if (maybe_ne (GET_MODE_PRECISION (mode), nunits))
tmp = expand_binop (mode, and_optab, tmp,
- GEN_INT ((1 << nunits) - 1), target,
- true, OPTAB_WIDEN);
+ GEN_INT ((HOST_WIDE_INT_1U << nunits) - 1),
+ target, true, OPTAB_WIDEN);
if (tmp != target)
emit_move_insn (target, tmp);
break;
