#2530: Thorn Vectors fails to compile using gcc 8.X on POWER9

Reporter: Roland Haas Status: new Milestone: Version: development version Type: bug Priority: minor Component: EinsteinToolkit thorn

Comment (by Roland Haas):

It turns out it wants a cast to `vector double *` (see [http://openpowerfoundation.org/wp-content/uploads/resources/Intrinsics-Refer...) which does list both `vec_st(vector double x, long long int, double * )` and `vec_st(vector double x, long long int, vector double * )` and apparently gcc 8 only supports the latter one). So this:

```c++ #if 0 g++ -c -g3 -mcpu=power9 -mvsx -O1 -Wall $@ $0 exit #endif

#include <altivec.h>

void foo(vector double x, double &p, double &q, double &r, double &s) { const long long null = 0; *(vector double*)&p = x; vec_vsx_st(x, null, &q); vec_st(x, null, (vector double*)&r); } ```

and produces code:

```plaintext Disassembly of section .text:

0000000000000000 <_Z3fooDv2_dRdS0_S0_S0_>: #include <altivec.h>

void foo(vector double x, double &p, double &q, double &r, double &s) { const long long null = 0; *(vector double*)&p = x; 0: 0d 00 45 f4 stxv vs34,0(r5) vec_vsx_st(x, null, &q); 4: 0d 00 46 f4 stxv vs34,0(r6) vec_st(x, null, (vector double*)&r); 8: ce 39 40 7c stvx v2,0,r7 } c: 20 00 80 4e blr 10: 00 00 00 00 .long 0x0 14: 00 09 00 00 .long 0x900 18: 00 00 00 00 .long 0x0 ```

where `stvx` is the regular altivec one and `stxv` is the ISA3 (POWER9) instruction.

-- Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2530/thorn-vectors-fail...