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* [gcc r14-155] aarch64: Emit single-instruction for smin (x, 0) and smax (x, 0)
@ 2023-04-21 18:07 Kyrylo Tkachov
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From: Kyrylo Tkachov @ 2023-04-21 18:07 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:88195141aea9561b26a72023c446ce9c1151340e
commit r14-155-g88195141aea9561b26a72023c446ce9c1151340e
Author: Kyrylo Tkachov <kyrylo.tkachov@arm.com>
Date: Fri Apr 21 19:06:37 2023 +0100
aarch64: Emit single-instruction for smin (x, 0) and smax (x, 0)
Motivated by https://reviews.llvm.org/D148249, we can expand to a single instruction
for the SMIN (x, 0) and SMAX (x, 0) cases using the combined AND/BIC and ASR operations.
Given that we already have well-fitting TARGET_CSSC patterns and expanders for the min/max codes
in the backend this patch does some minor refactoring to ensure we emit the right SMAX/SMIN RTL codes
for TARGET_CSSC, fall back to the generic expanders or emit a simple SMIN/SMAX with 0 RTX for !TARGET_CSSC
that is now matched by a separate pattern.
Bootstrapped and tested on aarch64-none-linux-gnu.
gcc/ChangeLog:
* config/aarch64/aarch64.md (aarch64_umax<mode>3_insn): Delete.
(umax<mode>3): Emit raw UMAX RTL instead of going through gen_ function
for umax.
(<optab><mode>3): New define_expand for MAXMIN_NOUMAX codes.
(*aarch64_<optab><mode>3_zero): Define.
(*aarch64_<optab><mode>3_cssc): Likewise.
* config/aarch64/iterators.md (maxminand): New code attribute.
gcc/testsuite/ChangeLog:
* gcc.target/aarch64/sminmax-asr_1.c: New test.
Diff:
---
gcc/config/aarch64/aarch64.md | 50 ++++++++++++++------
gcc/config/aarch64/iterators.md | 2 +
gcc/testsuite/gcc.target/aarch64/sminmax-asr_1.c | 60 ++++++++++++++++++++++++
3 files changed, 97 insertions(+), 15 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index f46d738b8c6..eaa87bf0276 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -4412,17 +4412,6 @@
[(set_attr "type" "csel")]
)
-(define_insn "aarch64_umax<mode>3_insn"
- [(set (match_operand:GPI 0 "register_operand" "=r,r")
- (umax:GPI (match_operand:GPI 1 "register_operand" "r,r")
- (match_operand:GPI 2 "aarch64_uminmax_operand" "r,Uum")))]
- "TARGET_CSSC"
- "@
- umax\\t%<w>0, %<w>1, %<w>2
- umax\\t%<w>0, %<w>1, %2"
- [(set_attr "type" "alu_sreg,alu_imm")]
-)
-
;; If X can be loaded by a single CNT[BHWD] instruction,
;;
;; A = UMAX (B, X)
@@ -4466,8 +4455,8 @@
operands[1] = force_reg (<MODE>mode, operands[1]);
if (!aarch64_uminmax_operand (operands[2], <MODE>mode))
operands[2] = force_reg (<MODE>mode, operands[2]);
- emit_insn (gen_aarch64_umax<mode>3_insn (operands[0], operands[1],
- operands[2]));
+ emit_move_insn (operands[0], gen_rtx_UMAX (<MODE>mode, operands[1],
+ operands[2]));
DONE;
}
else
@@ -6759,9 +6748,30 @@
[(set_attr "type" "ffarith<stype>")]
)
-(define_insn "<optab><mode>3"
+;; Expander for integer smin, smax, umin. Mainly used to generate
+;; straightforward RTL for TARGET_CSSC. When that is not available
+;; FAIL and let the generic expanders generate the CMP + CSEL sequences,
+;; except for the SMIN and SMAX with zero cases, for which we have a
+;; single instruction even for the base architecture.
+(define_expand "<optab><mode>3"
+ [(set (match_operand:GPI 0 "register_operand")
+ (MAXMIN_NOUMAX:GPI
+ (match_operand:GPI 1 "register_operand")
+ (match_operand:GPI 2 "aarch64_<su>minmax_operand")))]
+ ""
+ {
+ if (!TARGET_CSSC)
+ {
+ if (operands[2] != CONST0_RTX (<MODE>mode)
+ || !(<CODE> == SMAX || <CODE> == SMIN))
+ FAIL;
+ }
+ }
+)
+
+(define_insn "*aarch64_<optab><mode>3_cssc"
[(set (match_operand:GPI 0 "register_operand" "=r,r")
- (MAXMIN_NOUMAX:GPI (match_operand:GPI 1 "register_operand" "r,r")
+ (MAXMIN:GPI (match_operand:GPI 1 "register_operand" "r,r")
(match_operand:GPI 2 "aarch64_<su>minmax_operand" "r,U<su>m")))]
"TARGET_CSSC"
"@
@@ -6770,6 +6780,16 @@
[(set_attr "type" "alu_sreg,alu_imm")]
)
+(define_insn "*aarch64_<optab><mode>3_zero"
+ [(set (match_operand:GPI 0 "register_operand" "=r")
+ (FMAXMIN:GPI
+ (match_operand:GPI 1 "register_operand" "r")
+ (const_int 0)))]
+ ""
+ "<maxminand>\\t%<w>0, %<w>1, %<w>1, asr <sizem1>";
+ [(set_attr "type" "logic_shift_imm")]
+)
+
;; Given that smax/smin do not specify the result when either input is NaN,
;; we could use either FMAXNM or FMAX for smax, and either FMINNM or FMIN
;; for smin.
diff --git a/gcc/config/aarch64/iterators.md b/gcc/config/aarch64/iterators.md
index d3c43a212a1..d0184c84a0b 100644
--- a/gcc/config/aarch64/iterators.md
+++ b/gcc/config/aarch64/iterators.md
@@ -2435,6 +2435,8 @@
(umax "max")
(umin "min")])
+(define_code_attr maxminand [(smax "bic") (smin "and")])
+
;; MLA/MLS attributes.
(define_code_attr as [(ss_plus "a") (ss_minus "s")])
diff --git a/gcc/testsuite/gcc.target/aarch64/sminmax-asr_1.c b/gcc/testsuite/gcc.target/aarch64/sminmax-asr_1.c
new file mode 100644
index 00000000000..63396ecdafa
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sminmax-asr_1.c
@@ -0,0 +1,60 @@
+/* { dg-do compile } */
+/* { dg-options "-O --save-temps" } */
+/* { dg-final { check-function-bodies "**" "" "" } } */
+
+#include <stdint.h>
+
+#pragma GCC target "+nocssc"
+
+#define MAX(X, Y) ((X) > (Y) ? (X) : (Y))
+#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
+
+
+/*
+** minzero:
+** and w0, w0, w0, asr #31
+** ret
+*/
+
+int32_t
+minzero (int32_t a)
+{
+ return MIN (a, 0);
+}
+
+/*
+** maxzero:
+** bic w0, w0, w0, asr #31
+** ret
+*/
+
+int32_t
+maxzero (int32_t a)
+{
+ return MAX (a, 0);
+}
+
+/*
+** minzerol:
+** and x0, x0, x0, asr #63
+** ret
+*/
+
+int64_t
+minzerol (int64_t a)
+{
+ return MIN (a, 0);
+}
+
+/*
+** maxzerol:
+** bic x0, x0, x0, asr #63
+** ret
+*/
+
+int64_t
+maxzerol (int64_t a)
+{
+ return MAX (a, 0);
+}
+
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