Hi!
The following testcase is miscompiled, because the AVX2 patterns don't
describe correctly what the insn does. E.g. vphaddd with %ymm* operands
(the second pattern) instruction as per:
https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_mm256_hadd_epi32&expand=2941
does { a0+a1, a2+a3, b0+b1, b2+b3, a4+a5, a6+a7, b4+b5, b6+b7 }
but our RTL pattern did
{ a0+a1, a2+a3, a4+a5, a6+a7, b0+b1, b2+b3, b4+b5, b6+b7 }
where the first and last 64 bits are the same and two middle 64 bits
swapped.
https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_mm256_hadd_epi16&expand=2939
similarly, insn does:
{ a0+a1, a2+a3, a4+a5, a6+a7, b0+b1, b2+b3, b4+b5, b6+b7,
a8+a9, a10+a11, a12+a13, a14+a15, b8+b9, b10+b11, b12+b13, b14+b15 }
but RTL pattern did
{ a0+a1, a2+a3, a4+a5, a6+a7, a8+a9, a10+a11, a12+a13, a14+a15,
b0+b1, b2+b3, b4+b5, b6+b7, b8+b9, b10+b11, b12+b13, b14+b15 }
again, first and last 64 bits are the same and the two middle 64 bits
swapped.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?
As a follow-up for GCC11, I have simplification for the patterns.
2020-04-03 Jakub Jelinek <ja...@redhat.com>
PR target/94460
* config/i386/sse.md (avx2_ph<plusminus_mnemonic>wv16hi3,
avx2_ph<plusminus_mnemonic>dv8si3): Fix up RTL pattern to do
second half of first lane from first lane of second operand and
first half of second lane from second lane of first operand.
* gcc.target/i386/avx2-pr94460.c: New test.
--- gcc/config/i386/sse.md.jj 2020-03-30 18:04:31.942435289 +0200
+++ gcc/config/i386/sse.md 2020-04-03 10:21:51.110564277 +0200
@@ -16060,22 +16060,6 @@ (define_insn "avx2_ph<plusminus_mnemonic
(vec_concat:V4HI
(vec_concat:V2HI
(ssse3_plusminus:HI
- (vec_select:HI (match_dup 1) (parallel [(const_int 8)]))
- (vec_select:HI (match_dup 1) (parallel [(const_int 9)])))
- (ssse3_plusminus:HI
- (vec_select:HI (match_dup 1) (parallel [(const_int 10)]))
- (vec_select:HI (match_dup 1) (parallel [(const_int 11)]))))
- (vec_concat:V2HI
- (ssse3_plusminus:HI
- (vec_select:HI (match_dup 1) (parallel [(const_int 12)]))
- (vec_select:HI (match_dup 1) (parallel [(const_int 13)])))
- (ssse3_plusminus:HI
- (vec_select:HI (match_dup 1) (parallel [(const_int 14)]))
- (vec_select:HI (match_dup 1) (parallel [(const_int 15)]))))))
- (vec_concat:V8HI
- (vec_concat:V4HI
- (vec_concat:V2HI
- (ssse3_plusminus:HI
(vec_select:HI
(match_operand:V16HI 2 "nonimmediate_operand" "xm")
(parallel [(const_int 0)]))
@@ -16089,7 +16073,23 @@ (define_insn "avx2_ph<plusminus_mnemonic
(vec_select:HI (match_dup 2) (parallel [(const_int 5)])))
(ssse3_plusminus:HI
(vec_select:HI (match_dup 2) (parallel [(const_int 6)]))
- (vec_select:HI (match_dup 2) (parallel [(const_int 7)])))))
+ (vec_select:HI (match_dup 2) (parallel [(const_int 7)]))))))
+ (vec_concat:V8HI
+ (vec_concat:V4HI
+ (vec_concat:V2HI
+ (ssse3_plusminus:HI
+ (vec_select:HI (match_dup 1) (parallel [(const_int 8)]))
+ (vec_select:HI (match_dup 1) (parallel [(const_int 9)])))
+ (ssse3_plusminus:HI
+ (vec_select:HI (match_dup 1) (parallel [(const_int 10)]))
+ (vec_select:HI (match_dup 1) (parallel [(const_int 11)]))))
+ (vec_concat:V2HI
+ (ssse3_plusminus:HI
+ (vec_select:HI (match_dup 1) (parallel [(const_int 12)]))
+ (vec_select:HI (match_dup 1) (parallel [(const_int 13)])))
+ (ssse3_plusminus:HI
+ (vec_select:HI (match_dup 1) (parallel [(const_int 14)]))
+ (vec_select:HI (match_dup 1) (parallel [(const_int 15)])))))
(vec_concat:V4HI
(vec_concat:V2HI
(ssse3_plusminus:HI
@@ -16224,21 +16224,21 @@ (define_insn "avx2_ph<plusminus_mnemonic
(vec_select:SI (match_dup 1) (parallel [(const_int 3)]))))
(vec_concat:V2SI
(plusminus:SI
- (vec_select:SI (match_dup 1) (parallel [(const_int 4)]))
- (vec_select:SI (match_dup 1) (parallel [(const_int 5)])))
- (plusminus:SI
- (vec_select:SI (match_dup 1) (parallel [(const_int 6)]))
- (vec_select:SI (match_dup 1) (parallel [(const_int 7)])))))
- (vec_concat:V4SI
- (vec_concat:V2SI
- (plusminus:SI
(vec_select:SI
(match_operand:V8SI 2 "nonimmediate_operand" "xm")
(parallel [(const_int 0)]))
(vec_select:SI (match_dup 2) (parallel [(const_int 1)])))
(plusminus:SI
(vec_select:SI (match_dup 2) (parallel [(const_int 2)]))
- (vec_select:SI (match_dup 2) (parallel [(const_int 3)]))))
+ (vec_select:SI (match_dup 2) (parallel [(const_int 3)])))))
+ (vec_concat:V4SI
+ (vec_concat:V2SI
+ (plusminus:SI
+ (vec_select:SI (match_dup 1) (parallel [(const_int 4)]))
+ (vec_select:SI (match_dup 1) (parallel [(const_int 5)])))
+ (plusminus:SI
+ (vec_select:SI (match_dup 1) (parallel [(const_int 6)]))
+ (vec_select:SI (match_dup 1) (parallel [(const_int 7)]))))
(vec_concat:V2SI
(plusminus:SI
(vec_select:SI (match_dup 2) (parallel [(const_int 4)]))
--- gcc/testsuite/gcc.target/i386/avx2-pr94460.c.jj 2020-04-03
11:21:20.932237701 +0200
+++ gcc/testsuite/gcc.target/i386/avx2-pr94460.c 2020-04-03
11:20:55.566617063 +0200
@@ -0,0 +1,31 @@
+/* PR target/94460 */
+/* { dg-do run { target { avx2 && int128 } } } */
+/* { dg-options "-O2 -mavx2" } */
+
+#include <x86intrin.h>
+#include "avx2-check.h"
+
+typedef __int128 v2ti __attribute__ ((__vector_size__ (32)));
+
+static inline v2ti
+foo (__v16hi b)
+{
+ return (v2ti) _mm256_hsub_epi16 ((__m256i) b, (__m256i) b);
+}
+
+static inline v2ti
+bar (__v8si b)
+{
+ return (v2ti) _mm256_hsub_epi32 ((__m256i) b, (__m256i) b);
+}
+
+static void
+avx2_test (void)
+{
+ v2ti x = foo ((__v16hi) { 1 });
+ if (x[0] != ((__int128)1 << 64 | 1) || x[1] != 0)
+ abort ();
+ x = bar ((__v8si) { 1 });
+ if (x[0] != ((__int128)1 << 64 | 1) || x[1] != 0)
+ abort ();
+}
Jakub
