[Bug target/14945] New: SSE/MMX args passed in regs to variadic functions
rridge at csclub dot uwaterloo dot ca
gcc-bugzilla@gcc.gnu.org
Tue Apr 13 22:00:00 GMT 2004
When SSE/MMX vector types are passed to functions taking a variable
number of arguments, they're passed in registers instead of on
the stack where the called function expects them.
Test case:
#include <stdio.h>
#include <stdarg.h>
typedef double __attribute__((vector_size(16))) V4DF;
V4DF foo(int n, ...) {
va_list ap;
int i;
static V4DF ret ;
va_start(ap, n);
for(i = 0; i < n; i++) {
ret = va_arg(ap, V4DF);
}
va_end(ap);
return ret;
}
int
main() {
union {
V4DF v;
double d[2];
} u;
u.d[0] = 2.0;
u.d[1] = 2.0;
u.v = foo(1, u.v, 10.0, 10.0, 10.0, 10.0);
printf("(%f,%f)\n", u.d[0], u.d[1]);
return 0;
}
Compile with "gcc -msse2 t.c" and run. Output is:
(10.000000,10.000000)
Expected output is:
(2.000000,2.000000)
The output of "gcc -v":
Reading specs from E:/UTIL/GCCHEAD/MINGW/BIN/../lib/gcc/mingw32/3.5.0/specs
Configured with: ../gcc/configure --prefix=e:/util/gcchead/mingw --target=mingw3
2 --host=mingw32 --enable-languages=c,c++
Thread model: single
gcc version 3.5.0 20040406 (experimental)
The problem seems to be in file "i386.c", function "init_cumulative_args":
if (cum->nregs || !TARGET_MMX || !TARGET_SSE)
should be:
if (cum->nregs || TARGET_MMX || TARGET_SSE)
--
Summary: SSE/MMX args passed in regs to variadic functions
Product: gcc
Version: 3.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: rridge at csclub dot uwaterloo dot ca
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: i386-pc-mingw32
GCC host triplet: i386-pc-mingw32
GCC target triplet: i386-pc-mingw32
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14945
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