Hi,
The *vsx_extract_<mode>_load pattern performs a scalar load of memory
when possible, rather than a vector load followed by an extract. The
assembly for the pattern always loads the 0th memory doubleword element,
but the pattern match selects the 0th for big-endian and the 1st for
little-endian, leading to wrong results for LE. This patch changes the
pattern match to look for the 0th element regardless of endianness.
I ran across this when working on another patch, which provides more
test coverage for this scenario and will be submitted shortly. For this
patch, I'm just correcting the now-failing vsx-extract-1.c test.
Bootstrapped and tested on powerpc64le-unknown-linux-gnu with no
regressions. Ok for trunk? (This should eventually be backported to
4.8 and 4.9 as well...)
Thanks,
Bill
[gcc]
2014-09-03 Bill Schmidt <wschm...@linux.vnet.ibm.com>
* config/rs6000/vsx.md (*vsx_extract_<mode>_load): Always match
selection of 0th memory doubleword, regardless of endianness.
[gcc/testsuite]
2014-09-03 Bill Schmidt <wschm...@linux.vnet.ibm.com>
* gcc.target/powerpc/vsx-extract-1.c: Test 0th doubleword
regardless of endianness.
Index: gcc/config/rs6000/vsx.md
===================================================================
--- gcc/config/rs6000/vsx.md (revision 214897)
+++ gcc/config/rs6000/vsx.md (working copy)
@@ -1835,7 +1835,7 @@
[(set (match_operand:<VS_scalar> 0 "register_operand" "=d,wv,wr")
(vec_select:<VS_scalar>
(match_operand:VSX_D 1 "memory_operand" "m,Z,m")
- (parallel [(match_operand:QI 2 "vsx_scalar_64bit" "wD,wD,wD")])))]
+ (parallel [(const_int 0)])))]
"VECTOR_MEM_VSX_P (<MODE>mode)"
"@
lfd%U1%X1 %0,%1
Index: gcc/testsuite/gcc.target/powerpc/vsx-extract-1.c
===================================================================
--- gcc/testsuite/gcc.target/powerpc/vsx-extract-1.c (revision 214897)
+++ gcc/testsuite/gcc.target/powerpc/vsx-extract-1.c (working copy)
@@ -7,10 +7,4 @@
#include <altivec.h>
-#if __LITTLE_ENDIAN__
-#define OFFSET 1
-#else
-#define OFFSET 0
-#endif
-
-double get_value (vector double *p) { return vec_extract (*p, OFFSET); }
+double get_value (vector double *p) { return vec_extract (*p, 0); }
