From: Li Wei <liwei@loongson.cn>
To: gcc-patches@gcc.gnu.org
Cc: xry111@xry111.site, i@xen0n.name, xuchenghua@loongson.cn,
chenglulu@loongson.cn, Li Wei <liwei@loongson.cn>
Subject: [PATCH v1] LoongArch: Implement C[LT]Z_DEFINED_VALUE_AT_ZERO
Date: Thu, 16 Nov 2023 20:30:04 +0800 [thread overview]
Message-ID: <20231116123004.3731806-1-liwei@loongson.cn> (raw)
The LoongArch has defined ctz and clz on the backend, but if we want GCC
do CTZ transformation optimization in forwprop2 pass, GCC need to know
the value of c[lt]z at zero, which may be beneficial for some test cases
(like spec2017 deepsjeng_r).
After implementing the macro, we test dynamic instruction count on
deepsjeng_r:
- before 1688423249186
- after 1660311215745 (1.66% reduction)
---
gcc/config/loongarch/loongarch.h | 5 +++++
gcc/testsuite/gcc.dg/pr90838.c | 5 +++++
2 files changed, 10 insertions(+)
diff --git a/gcc/config/loongarch/loongarch.h b/gcc/config/loongarch/loongarch.h
index ddac8e98ea9..115222e70fd 100644
--- a/gcc/config/loongarch/loongarch.h
+++ b/gcc/config/loongarch/loongarch.h
@@ -1239,3 +1239,8 @@ struct GTY (()) machine_function
#define TARGET_EXPLICIT_RELOCS \
(la_opt_explicit_relocs == EXPLICIT_RELOCS_ALWAYS)
+
+#define CLZ_DEFINED_VALUE_AT_ZERO(MODE, VALUE) \
+ ((VALUE) = GET_MODE_UNIT_BITSIZE (MODE), 2)
+#define CTZ_DEFINED_VALUE_AT_ZERO(MODE, VALUE) \
+ ((VALUE) = GET_MODE_UNIT_BITSIZE (MODE), 2)
diff --git a/gcc/testsuite/gcc.dg/pr90838.c b/gcc/testsuite/gcc.dg/pr90838.c
index 759059683a9..40aad70499d 100644
--- a/gcc/testsuite/gcc.dg/pr90838.c
+++ b/gcc/testsuite/gcc.dg/pr90838.c
@@ -83,3 +83,8 @@ int ctz4 (unsigned long x)
/* { dg-final { scan-assembler-times "ctz\t" 3 { target { rv32 } } } } */
/* { dg-final { scan-assembler-times "andi\t" 1 { target { rv32 } } } } */
/* { dg-final { scan-assembler-times "mul\t" 1 { target { rv32 } } } } */
+
+/* { dg-final { scan-tree-dump-times {= \.CTZ} 4 "forwprop2" { target { loongarch64*-*-* } } } } */
+/* { dg-final { scan-assembler-times "ctz.d\t" 1 { target { loongarch64*-*-* } } } } */
+/* { dg-final { scan-assembler-times "ctz.w\t" 3 { target { loongarch64*-*-* } } } } */
+/* { dg-final { scan-assembler-times "andi\t" 4 { target { loongarch64*-*-* } } } } */
--
2.31.1
next reply other threads:[~2023-11-16 12:30 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-16 12:30 Li Wei [this message]
2023-11-16 12:45 ` Xi Ruoyao
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