On Thu, Dec 12, 2019 at 04:59:40PM +0100, Richard Biener wrote:
> >If it starts being ambiguous somewhere, could we use some target macro
> >or
> >target hook to decide?
>
> Ambiguous IL is bad :/ IL semantics dependent on a target hook, too. Just
> look at SHIFT_COUNT_TRUNCATED...
This is something I've also successfully bootstrapped/regtested on
x86_64-linux and i686-linux:
2019-12-11 Jakub Jelinek <ja...@redhat.com>
PR target/92908
* simplify-rtx.c (simplify_relational_operation): Punt for vector
cmp_mode and scalar mode, if simplify_relational_operation returned
const_true_rtx.
(simplify_const_relational_operation): Change VOID_mode in function
comment to VOIDmode.
* gcc.target/i386/avx512bw-pr92908.c: New test.
--- gcc/simplify-rtx.c.jj 2019-11-19 22:27:02.000058742 +0100
+++ gcc/simplify-rtx.c 2019-12-11 13:31:57.197809704 +0100
@@ -5037,6 +5037,15 @@ simplify_relational_operation (enum rtx_
return NULL_RTX;
#endif
}
+ /* For vector comparison with scalar int result, it is unknown
+ if the target means here a comparison into an integral bitmask,
+ or comparison where all comparisons true mean const_true_rtx
+ whole result, or where any comparisons true mean const_true_rtx
+ whole result. For const0_rtx all the cases are the same. */
+ if (VECTOR_MODE_P (cmp_mode)
+ && SCALAR_INT_MODE_P (mode)
+ && tem == const_true_rtx)
+ return NULL_RTX;
return tem;
}
@@ -5383,7 +5392,7 @@ comparison_result (enum rtx_code code, i
}
/* Check if the given comparison (done in the given MODE) is actually
- a tautology or a contradiction. If the mode is VOID_mode, the
+ a tautology or a contradiction. If the mode is VOIDmode, the
comparison is done in "infinite precision". If no simplification
is possible, this function returns zero. Otherwise, it returns
either const_true_rtx or const0_rtx. */
--- gcc/testsuite/gcc.target/i386/avx512bw-pr92908.c.jj 2019-12-11
14:24:12.083418762 +0100
+++ gcc/testsuite/gcc.target/i386/avx512bw-pr92908.c 2019-12-11
14:23:56.071665326 +0100
@@ -0,0 +1,21 @@
+/* PR target/92908 */
+/* { dg-do run } */
+/* { dg-options "-Og -fno-tree-fre -mavx512bw" } */
+/* { dg-require-effective-target avx512bw } */
+
+#define AVX512BW
+#include "avx512f-helper.h"
+
+typedef unsigned short V __attribute__ ((__vector_size__ (64)));
+
+V v;
+
+void
+TEST (void)
+{
+ int i;
+ v = (V) v == v;
+ for (i = 0; i < 32; i++)
+ if (v[i] != 0xffff)
+ abort ();
+}
Jakub
