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[mips] Change the definition of macro SHIFT_COUNT_TRUNCATED
- From: Mingjie Xing <mingjie dot xing at gmail dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Sat, 28 Aug 2010 16:57:42 +0800
- Subject: [mips] Change the definition of macro SHIFT_COUNT_TRUNCATED
Hello,
This patch change the definition of macro SHIFT_COUNT_TRUNCATED. This
can fix the bug on Loongson for such an test case,
/* { dg-do run } */
/* { dg-options "isa=loongson -mhard-float -mno-mips16 -O1" } */
#include "loongson.h"
#include <assert.h>
typedef union { int32x2_t v; int32_t a[2]; } int32x2_encap_t;
void
main1 (int shift)
{
int32x2_encap_t s;
int32x2_encap_t r;
s.a[0] = 0xffffffff;
s.a[1] = 0xffffffff;
/* Loongson SIMD use low-order 7 bits to specify the shift amount. Thus
V2SI << 0x40 == 0. The below expression 'shift & 0x3f' will be mis-optimized
as 'shift', if SHIFT_COUNT_TRUNCATED is nonzero. */
r.v = psllw_s (s.v, (shift & 0x3f));
assert (r.a[0] == 0xffffffff);
assert (r.a[1] == 0xffffffff);
}
int
main (void)
{
main1 (0x40);
return 0;
}
ChangeLog:
2010-08-28 Mingjie Xing <mingjie.xing@gmail.com>
* config/mips/mips.h (SHIFT_COUNT_TRUNCATED) : Define to 0 for
Loongson targets, 1 otherwise.
Is it OK?
BTW, I'm not sure if I should commit the test case.
Thanks,
Mingjie
Index: config/mips/mips.h
===================================================================
--- config/mips/mips.h (revision 163612)
+++ config/mips/mips.h (working copy)
@@ -2422,8 +2422,11 @@ typedef struct mips_args {
#define SLOW_BYTE_ACCESS (!TARGET_MIPS16)
/* Define this to be nonzero if shift instructions ignore all but the low-order
- few bits. */
-#define SHIFT_COUNT_TRUNCATED 1
+ few bits.
+
+ For Loongson targets, the Loongson specific vector shift instructions are
+ not SHIFT_COUNT_TRUNCATED. */
+#define SHIFT_COUNT_TRUNCATED (TARGET_LOONGSON_2EF ? 0 : 1)
/* Value is 1 if truncating an integer of INPREC bits to OUTPREC bits
is done just by pretending it is already truncated. */