[Bug c/63663] New: [NEON] wrong value when computing the leading zero of int16x4_t type at O2
spf_zju at 126 dot com
gcc-bugzilla@gcc.gnu.org
Tue Oct 28 02:25:00 GMT 2014
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63663
Bug ID: 63663
Summary: [NEON] wrong value when computing the leading zero
of int16x4_t type at O2
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: spf_zju at 126 dot com
the 1.c code is :
#include <arm_neon.h>
#include <stdio.h>
int main()
{
int16x4_t vector_int16x4;
int16x4_t vector_res_int16x4;
vector_int16x4 = vdup_n_s16(0);
vector_res_int16x4 = vclz_s16(vector_int16x4);
return vector_res_int16x4[0];
}
compiled with :armeb-linux-gnueabi-gcc -S -O2 -mfloat-abi=softfp -mfpu=neon
1.c
the assembly:
main:
@ args = 0, pretend = 0, frame = 0
@ frame_needed = 0, uses_anonymous_args = 0
@ link register save eliminated.
mov r0, #32
bx lr
the main should return #16,not #32.
this bug appears in the trunk snapshot 20141026.
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