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Diffstat (limited to 'src/cmd/compile/internal/ssa/gen/RISCV64.rules')
-rw-r--r--src/cmd/compile/internal/ssa/gen/RISCV64.rules14
1 files changed, 14 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/gen/RISCV64.rules b/src/cmd/compile/internal/ssa/gen/RISCV64.rules
index 3bc2e8498a..325cbeb825 100644
--- a/src/cmd/compile/internal/ssa/gen/RISCV64.rules
+++ b/src/cmd/compile/internal/ssa/gen/RISCV64.rules
@@ -360,6 +360,13 @@
(Zero [4] ptr mem) => (MOVWstore ptr (MOVWconst) mem)
(Zero [8] ptr mem) => (MOVDstore ptr (MOVDconst) mem)
+// Medium zeroing uses a Duff's device
+// 8 and 128 are magic constants, see runtime/mkduff.go
+(Zero [s] {t} ptr mem)
+ && s%8 == 0 && s >= 16 && s <= 8*128
+ && t.Alignment()%8 == 0 && !config.noDuffDevice =>
+ (DUFFZERO [8 * (128 - s/8)] ptr mem)
+
// Generic zeroing uses a loop
(Zero [s] {t} ptr mem) =>
(LoweredZero [t.Alignment()]
@@ -395,6 +402,13 @@
(Move [4] dst src mem) => (MOVWstore dst (MOVWload src mem) mem)
(Move [8] dst src mem) => (MOVDstore dst (MOVDload src mem) mem)
+// Medium move uses a Duff's device
+// 16 and 128 are magic constants, see runtime/mkduff.go
+(Move [s] {t} dst src mem)
+ && s%8 == 0 && s >= 16 && s <= 8*128 && t.Alignment()%8 == 0
+ && !config.noDuffDevice && logLargeCopy(v, s) =>
+ (DUFFCOPY [16 * (128 - s/8)] dst src mem)
+
// Generic move uses a loop
(Move [s] {t} dst src mem) && (s <= 16 || logLargeCopy(v, s)) =>
(LoweredMove [t.Alignment()]