* Use q modifier for XMM portion of an YMM register?
@ 2016-09-01 8:11 Adam Warner
0 siblings, 0 replies; only message in thread
From: Adam Warner @ 2016-09-01 8:11 UTC (permalink / raw)
To: gcc-help
Hello all,
This seems to work:
#include <stdint.h>
typedef uint64_t u64x4_t __attribute__ ((vector_size (32)));
int main(void) {
register u64x4_t abcd asm("ymm0");
register u64x4_t efgh asm("ymm1");
asm volatile ("vextractf128 $1, %1, %q0" : "=x" (abcd) : "x" (efgh));
}
$ gcc-snapshot.sh -O3 -mavx q-modifier.c
$ objdump -d -m i386:x86-64:intel a.out |less
...
c4 e3 7d 19 c8 01 vextractf128 xmm0,ymm1,0x1
...
If the approach is correct I could inform the clang project of the syntax
(it's an internal compiler error in clang-3.9).
Regards,
Adam Warner
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