cmd/compile: avoid extending when already sufficiently masked on riscv64

Removes more than 2000 instructions from the Go binary on linux/risv64.

Change-Id: I6db3e3b1c93f29f00869adcba7c6192bfb90b25c
Reviewed-on: https://go-review.googlesource.com/c/go/+/426259
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-by: Wayne Zuo <wdvxdr@golangcn.org>
Reviewed-by: Meng Zhuo <mzh@golangcn.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>

diff --git a/src/cmd/compile/internal/ssa/gen/RISCV64.rules b/src/cmd/compile/internal/ssa/gen/RISCV64.rules
index 9ba0d9c1af358c5b0f4fab5cf9e5980189045b70..ee82c15f95df278f8aae620e87c0474aeb4686af 100644 (file)
--- a/src/cmd/compile/internal/ssa/gen/RISCV64.rules
+++ b/src/cmd/compile/internal/ssa/gen/RISCV64.rules
@@ -633,6 +633,14 @@
 (MOVBUreg x:((SEQZ|SNEZ) _)) => x
 (MOVBUreg x:((SLT|SLTU) _ _)) => x
 
+// Avoid extending when already sufficiently masked.
+(MOVBreg  x:(ANDI [c] y)) && c >= 0 && int64(int8(c)) == c => x
+(MOVHreg  x:(ANDI [c] y)) && c >= 0 && int64(int16(c)) == c => x
+(MOVWreg  x:(ANDI [c] y)) && c >= 0 && int64(int32(c)) == c => x
+(MOVBUreg x:(ANDI [c] y)) && c >= 0 && int64(uint8(c)) == c => x
+(MOVHUreg x:(ANDI [c] y)) && c >= 0 && int64(uint16(c)) == c => x
+(MOVWUreg x:(ANDI [c] y)) && c >= 0 && int64(uint32(c)) == c => x
+
 // Avoid sign/zero extension for consts.
 (MOVBreg  (MOVDconst [c])) => (MOVDconst [int64(int8(c))])
 (MOVHreg  (MOVDconst [c])) => (MOVDconst [int64(int16(c))])

diff --git a/src/cmd/compile/internal/ssa/rewriteRISCV64.go b/src/cmd/compile/internal/ssa/rewriteRISCV64.go
index 8e7bdc0a2a9fb9d871a17277cfecdee984431579..0aba7e70dbc20f404bcc02dc2cf7e2c8622e948e 100644 (file)
--- a/src/cmd/compile/internal/ssa/rewriteRISCV64.go
+++ b/src/cmd/compile/internal/ssa/rewriteRISCV64.go
@@ -3200,6 +3200,21 @@ func rewriteValueRISCV64_OpRISCV64MOVBUreg(v *Value) bool {
                v.copyOf(x)
                return true
        }
+       // match: (MOVBUreg x:(ANDI [c] y))
+       // cond: c >= 0 && int64(uint8(c)) == c
+       // result: x
+       for {
+               x := v_0
+               if x.Op != OpRISCV64ANDI {
+                       break
+               }
+               c := auxIntToInt64(x.AuxInt)
+               if !(c >= 0 && int64(uint8(c)) == c) {
+                       break
+               }
+               v.copyOf(x)
+               return true
+       }
        // match: (MOVBUreg (MOVDconst [c]))
        // result: (MOVDconst [int64(uint8(c))])
        for {
@@ -3310,6 +3325,21 @@ func rewriteValueRISCV64_OpRISCV64MOVBload(v *Value) bool {
 func rewriteValueRISCV64_OpRISCV64MOVBreg(v *Value) bool {
        v_0 := v.Args[0]
        b := v.Block
+       // match: (MOVBreg x:(ANDI [c] y))
+       // cond: c >= 0 && int64(int8(c)) == c
+       // result: x
+       for {
+               x := v_0
+               if x.Op != OpRISCV64ANDI {
+                       break
+               }
+               c := auxIntToInt64(x.AuxInt)
+               if !(c >= 0 && int64(int8(c)) == c) {
+                       break
+               }
+               v.copyOf(x)
+               return true
+       }
        // match: (MOVBreg (MOVDconst [c]))
        // result: (MOVDconst [int64(int8(c))])
        for {
@@ -3831,6 +3861,21 @@ func rewriteValueRISCV64_OpRISCV64MOVHUload(v *Value) bool {
 func rewriteValueRISCV64_OpRISCV64MOVHUreg(v *Value) bool {
        v_0 := v.Args[0]
        b := v.Block
+       // match: (MOVHUreg x:(ANDI [c] y))
+       // cond: c >= 0 && int64(uint16(c)) == c
+       // result: x
+       for {
+               x := v_0
+               if x.Op != OpRISCV64ANDI {
+                       break
+               }
+               c := auxIntToInt64(x.AuxInt)
+               if !(c >= 0 && int64(uint16(c)) == c) {
+                       break
+               }
+               v.copyOf(x)
+               return true
+       }
        // match: (MOVHUreg (MOVDconst [c]))
        // result: (MOVDconst [int64(uint16(c))])
        for {
@@ -3963,6 +4008,21 @@ func rewriteValueRISCV64_OpRISCV64MOVHload(v *Value) bool {
 func rewriteValueRISCV64_OpRISCV64MOVHreg(v *Value) bool {
        v_0 := v.Args[0]
        b := v.Block
+       // match: (MOVHreg x:(ANDI [c] y))
+       // cond: c >= 0 && int64(int16(c)) == c
+       // result: x
+       for {
+               x := v_0
+               if x.Op != OpRISCV64ANDI {
+                       break
+               }
+               c := auxIntToInt64(x.AuxInt)
+               if !(c >= 0 && int64(int16(c)) == c) {
+                       break
+               }
+               v.copyOf(x)
+               return true
+       }
        // match: (MOVHreg (MOVDconst [c]))
        // result: (MOVDconst [int64(int16(c))])
        for {
@@ -4300,6 +4360,21 @@ func rewriteValueRISCV64_OpRISCV64MOVWUload(v *Value) bool {
 func rewriteValueRISCV64_OpRISCV64MOVWUreg(v *Value) bool {
        v_0 := v.Args[0]
        b := v.Block
+       // match: (MOVWUreg x:(ANDI [c] y))
+       // cond: c >= 0 && int64(uint32(c)) == c
+       // result: x
+       for {
+               x := v_0
+               if x.Op != OpRISCV64ANDI {
+                       break
+               }
+               c := auxIntToInt64(x.AuxInt)
+               if !(c >= 0 && int64(uint32(c)) == c) {
+                       break
+               }
+               v.copyOf(x)
+               return true
+       }
        // match: (MOVWUreg (MOVDconst [c]))
        // result: (MOVDconst [int64(uint32(c))])
        for {
@@ -4454,6 +4529,21 @@ func rewriteValueRISCV64_OpRISCV64MOVWload(v *Value) bool {
 func rewriteValueRISCV64_OpRISCV64MOVWreg(v *Value) bool {
        v_0 := v.Args[0]
        b := v.Block
+       // match: (MOVWreg x:(ANDI [c] y))
+       // cond: c >= 0 && int64(int32(c)) == c
+       // result: x
+       for {
+               x := v_0
+               if x.Op != OpRISCV64ANDI {
+                       break
+               }
+               c := auxIntToInt64(x.AuxInt)
+               if !(c >= 0 && int64(int32(c)) == c) {
+                       break
+               }
+               v.copyOf(x)
+               return true
+       }
        // match: (MOVWreg (MOVDconst [c]))
        // result: (MOVDconst [int64(int32(c))])
        for {