Hi,
GCC revision 259524 implemented range check for the vec_splat_{su}{8,16,32}
builtins. However, as a consequence of the implementation, the range check
is not done correctly for the expected vspltis[bhw] instructions. The result
is that we may not get a valid error message if the valid range of the data
is exceeded.
Although the input of the function prototype of vec_splat_{su}{8,16,32} is
const int, the actual data usage range is limited to the data range of 5 bits
signed. We should limit the int_cst.val[0] data to the 5 bit signed data range
without any modification in the input arg0 parameter. However, the sext_hwi
function intercepts the data of TREE_INT_CST_LOW (arg0) as size bits in the
sext_hwi (TREE_INT_CST_LOW (arg0), size) statement. This will cause some of
the excess data to fall within the range of 5 bits signed, so that the correct
diagnostic information cannot be generated, we need to remove the sext_hwi to
ensure that the input data has not been modified.
This patch fix range check for the vec_splat_s[8,16,32] builtins. The argument
must be a 5-bit const int as specified for the vspltis[bhw] instructions.
The regression testing for the patch was done on GCC mainline on
powerpc64le-unknown-linux-gnu (Power 8 LE)
with no regressions. Is it OK for trunk?
Thanks,
Lijia
---
gcc/ChangeLog
2019-02-15 Li Jia He <heli...@linux.ibm.com>
PR target/88100
* gcc/config/rs6000/rs6000.c (rs6000_gimple_fold_builtin): Remove
sext_hwi in IN_RANGE (sext_hwi (TREE_INT_CST_LOW (arg0), size),
-16, 15).
gcc/testsuite/ChangeLog
2019-02-15 Li Jia He <heli...@linux.ibm.com>
PR target/88100
* gcc/testsuite/gcc.target/powerpc/pr88100.c: New testcase.
---
gcc/config/rs6000/rs6000.c | 11 +-------
gcc/testsuite/gcc.target/powerpc/pr88100.c | 44 ++++++++++++++++++++++++++++++
2 files changed, 45 insertions(+), 10 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/powerpc/pr88100.c
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index aea7925..b1249bc 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -16105,22 +16105,13 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
case ALTIVEC_BUILTIN_VSPLTISH:
case ALTIVEC_BUILTIN_VSPLTISW:
{
- int size;
- if (fn_code == ALTIVEC_BUILTIN_VSPLTISB)
- size = 8;
- else if (fn_code == ALTIVEC_BUILTIN_VSPLTISH)
- size = 16;
- else
- size = 32;
-
arg0 = gimple_call_arg (stmt, 0);
lhs = gimple_call_lhs (stmt);
/* Only fold the vec_splat_*() if the lower bits of arg 0 is a
5-bit signed constant in range -16 to +15. */
if (TREE_CODE (arg0) != INTEGER_CST
- || !IN_RANGE (sext_hwi (TREE_INT_CST_LOW (arg0), size),
- -16, 15))
+ || !IN_RANGE (TREE_INT_CST_LOW (arg0), -16, 15))
return false;
gimple_seq stmts = NULL;
location_t loc = gimple_location (stmt);
diff --git a/gcc/testsuite/gcc.target/powerpc/pr88100.c
b/gcc/testsuite/gcc.target/powerpc/pr88100.c
new file mode 100644
index 0000000..4452145
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr88100.c
@@ -0,0 +1,44 @@
+/* PR88100. Verify that rs6000 gimple-folding code handles the
+ vec_splat_{su}{8,16,32} invalid data properly. */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target powerpc_altivec_ok } */
+/* { dg-options "-maltivec" } */
+
+#include <altivec.h>
+
+vector unsigned char
+splatu1 (void)
+{
+ return vec_splat_u8(0x100);/* { dg-error "argument 1 must be a 5-bit signed
literal" } */
+}
+
+vector unsigned short
+splatu2 (void)
+{
+ return vec_splat_u16(0x10000);/* { dg-error "argument 1 must be a 5-bit
signed literal" } */
+}
+
+vector unsigned int
+splatu3 (void)
+{
+ return vec_splat_u32(0x10000000);/* { dg-error "argument 1 must be a 5-bit
signed literal" } */
+}
+
+vector signed char
+splats1 (void)
+{
+ return vec_splat_s8(0x100);/* { dg-error "argument 1 must be a 5-bit signed
literal" } */
+}
+
+vector signed short
+splats2 (void)
+{
+ return vec_splat_s16(0x10000);/* { dg-error "argument 1 must be a 5-bit
signed literal" } */
+}
+
+vector signed int
+splats3 (void)
+{
+ return vec_splat_s32(0x10000000);/* { dg-error "argument 1 must be a 5-bit
signed literal" } */
+}
--
2.7.4
