https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95070
Bug ID: 95070
Summary: vec_cntlz_lsbb implementation uses BE semantics on LE
Product: gcc
Version: 8.3.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: pc at us dot ibm.com
Target Milestone: ---
Created attachment 48512
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48512&action=edit
test case
This:
--
vector unsigned char a = { 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
int r = vec_cntlz_lsbb (a);
--
returns 14 on LE and 0 on BE. It should return 0 on both.
vec_cntlz_lsbb counts bytes with least significant bits of 0 *starting from the
lowest element number*. In the above code, a[0] == 0xFF, so the count should
find 0 bytes.
The same issue occurs with vec_cnttz_lsbb (which should find 14 bytes in the
above example on both LE and BE, but finds 0 and 14, respectively).
