On 26/01/2023 15:02, Kyrylo Tkachov wrote:
Hi Andre,
-----Original Message-----
From: Andre Vieira (lists) <andre.simoesdiasvie...@arm.com>
Sent: Tuesday, January 24, 2023 1:41 PM
To: gcc-patches@gcc.gnu.org
Cc: Kyrylo Tkachov <kyrylo.tkac...@arm.com>; Richard Earnshaw
<richard.earns...@arm.com>
Subject: [PATCH 1/3] arm: Fix sign of MVE predicate mve_pred16_t [PR
107674]
Hi,
The ACLE defines mve_pred16_t as an unsigned short. This patch makes
sure GCC treats the predicate as an unsigned type, rather than signed.
Bootstrapped on aarch64-none-eabi and regression tested on arm-none-eabi
and armeb-none-eabi for armv8.1-m.main+mve.fp.
OK for trunk?
gcc/ChangeLog:
PR target/107674
* config/arm/arm-builtins.cc (arm_simd_builtin_type): Rewrite to
use
new qualifiers parameter and use unsigned short type for MVE
predicate.
(arm_init_builtin): Call arm_simd_builtin_type with qualifiers
parameter.
(arm_init_crypto_builtins): Likewise.
gcc/testsuite/ChangeLog:
PR target/107674
* gcc.target/arm/mve/mve_vpt.c: New test.
diff --git a/gcc/config/arm/arm-builtins.cc b/gcc/config/arm/arm-builtins.cc
index
11d7478d9df69139802a9d42c09dd0de7480b60e..6c67cec93ff76a4b42f3a0b305f697142e88fcd9
100644
--- a/gcc/config/arm/arm-builtins.cc
+++ b/gcc/config/arm/arm-builtins.cc
@@ -1489,12 +1489,14 @@ arm_lookup_simd_builtin_type (machine_mode mode,
}
static tree
-arm_simd_builtin_type (machine_mode mode, bool unsigned_p, bool poly_p)
+arm_simd_builtin_type (machine_mode mode, enum arm_type_qualifiers qualifiers)
{
I think in C++ now we can leave out the "enum" here.
diff --git a/gcc/testsuite/gcc.target/arm/mve/mve_vpt.c
b/gcc/testsuite/gcc.target/arm/mve/mve_vpt.c
new file mode 100644
index
0000000000000000000000000000000000000000..26a565b79dd1348e361b3aa23a1d6e6d13bffce8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/mve/mve_vpt.c
@@ -0,0 +1,27 @@
+/* { dg-options "-O2" } */
+/* { dg-require-effective-target arm_v8_1m_mve_ok } */
+/* { dg-add-options arm_v8_1m_mve } */
+/* { dg-final { check-function-bodies "**" "" } } */
+#include <arm_mve.h>
+void test0 (uint8_t *a, uint8_t *b, uint8_t *c)
+{
+ uint8x16_t va = vldrbq_u8 (a);
+ uint8x16_t vb = vldrbq_u8 (b);
+ mve_pred16_t p = vcmpeqq_u8 (va, vb);
+ uint8x16_t vc = vaddq_x_u8 (va, vb, p);
+ vstrbq_p_u8 (c, vc, p);
+}
+/*
+** test0:
+** vldrb.8 q2, \[r0\]
+** vldrb.8 q1, \[r1\]
+** vcmp.i8 eq, q2, q1
+** vmrs r3, p0 @ movhi
+** uxth r3, r3
+** vmsr p0, r3 @ movhi
+** vpst
+** vaddt.i8 q3, q2, q1
+** vpst
+** vstrbt.8 q3, \[r2\]
+** bx lr
+*/
This explicit assembly matching looks quite fragile and sensitive to future
scheduling and RA changes.
Is there something more targeted we could scan for to check that the predicate
is unsigned now?
No not really, as it's not unsigned everywhere, only in its intermediate
representation between intrinsics. GCC is aware that mve_pred16_t is an
unsigned short, so as soon as you try to use the value on its own or
pass it as an argument or return, there is an implicit cast.
I could make this particular test-case more robust by not checking
specific registers. Though the sequence of loads-cmp-add-store will
always be the same as it's data-dependent.
