From: Kyrylo Tkachov <kyrylo.tkachov@arm.com>
Date: Thu, 7 Jan 2021 14:02:02 +0000 (+0000)
Subject: aarch64: Fix RTL patterns for UABA/SABA
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c9d25aa7489fd478098e0ef098438e797d597d3b;p=gcc.git

aarch64: Fix RTL patterns for UABA/SABA

Sometime ago we changed the RTL representation of the (SU)ABD
instructions in RTL to a (MINUS (MAX) (MIN)) rather than a (MINUS (ABS) (ABS))
as it is more correctly models the semantics.
We should do the same for the accumulation forms of these instructions:
UABA/SABA.

This patch does that and allows the new pattern to generate the unsigned
UABA form as well.
The new form also allows it to more easily be re-used to implement the
relevant arm_neon.h intrinsics in the future.

The testcase takes an -fno-tree-reassoc to work around a side-effect of
PR98581.

gcc/
	* config/aarch64/aarch64-simd.md (aba<mode>_3): Rename to...
	(aarch64_<su>aba<mode>): ... This.  Handle uaba as well.
	Change RTL pattern to match.

gcc/testsuite/
	* gcc.target/aarch64/usaba_1.c: New test.
---

diff --git a/gcc/config/aarch64/aarch64-simd.md b/gcc/config/aarch64/aarch64-simd.md
index 85770c84f0a..d23398eac34 100644
--- a/gcc/config/aarch64/aarch64-simd.md
+++ b/gcc/config/aarch64/aarch64-simd.md
@@ -859,14 +859,18 @@
   }
 )
 
-(define_insn "aba<mode>_3"
+(define_insn "aarch64_<su>aba<mode>"
   [(set (match_operand:VDQ_BHSI 0 "register_operand" "=w")
-	(plus:VDQ_BHSI (abs:VDQ_BHSI (minus:VDQ_BHSI
-			 (match_operand:VDQ_BHSI 1 "register_operand" "w")
-			 (match_operand:VDQ_BHSI 2 "register_operand" "w")))
-		       (match_operand:VDQ_BHSI 3 "register_operand" "0")))]
-  "TARGET_SIMD"
-  "saba\t%0.<Vtype>, %1.<Vtype>, %2.<Vtype>"
+	(plus:VDQ_BHSI (minus:VDQ_BHSI
+			 (USMAX:VDQ_BHSI
+			   (match_operand:VDQ_BHSI 2 "register_operand" "w")
+			   (match_operand:VDQ_BHSI 3 "register_operand" "w"))
+			 (<max_opp>:VDQ_BHSI
+			   (match_dup 2)
+			   (match_dup 3)))
+		       (match_operand:VDQ_BHSI 1 "register_operand" "0")))]
+  "TARGET_SIMD"
+  "<su>aba\t%0.<Vtype>, %2.<Vtype>, %3.<Vtype>"
   [(set_attr "type" "neon_arith_acc<q>")]
 )
 
diff --git a/gcc/testsuite/gcc.target/aarch64/usaba_1.c b/gcc/testsuite/gcc.target/aarch64/usaba_1.c
new file mode 100644
index 00000000000..58b5bebdc94
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/usaba_1.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fno-tree-reassoc" } */
+
+#pragma GCC target "+nosve"
+
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+#define FUNC(T, N, S)	\
+void saba_##S (T * __restrict__ a, T * __restrict__ b, T * __restrict__ c)	\
+{	\
+  int i;	\
+  for (i = 0; i < N; i++)	\
+    c[i] += (MAX (a[i], b[i]) - MIN (a[i], b[i]));	\
+}
+
+FUNC (signed char, 16, qi)
+/* { dg-final { scan-assembler-times {saba\tv[0-9]+\.16b, v[0-9]+\.16b, v[0-9]+\.16b} 1 } } */
+FUNC (short, 8, hi)
+/* { dg-final { scan-assembler-times {saba\tv[0-9]+\.8h, v[0-9]+\.8h, v[0-9]+\.8h} 1 } } */
+FUNC (int, 4, si)
+/* { dg-final { scan-assembler-times {saba\tv[0-9]+\.4s, v[0-9]+\.4s, v[0-9]+\.4s} 1 } } */
+FUNC (unsigned char, 16, uqi)
+/* { dg-final { scan-assembler-times {uaba\tv[0-9]+\.16b, v[0-9]+\.16b, v[0-9]+.16b} 1 } } */
+FUNC (unsigned short, 8, uhi)
+/* { dg-final { scan-assembler-times {uaba\tv[0-9]+\.8h, v[0-9]+\.8h, v[0-9]+\.8h} 1 } } */
+FUNC (unsigned int, 4, usi)
+/* { dg-final { scan-assembler-times {uaba\tv[0-9]+\.4s, v[0-9]+\.4s, v[0-9]+\.4s} 1 } } */
+