cmd/compile: distribute 8 and 16-bit multiplication

Expand the existing rule to cover 8 and 16 bit variants.

compilecmp linux/amd64:

time
time.parseStrictRFC3339.func1 80 -> 70  (-12.50%)
time.Time.appendStrictRFC3339.func1 80 -> 70  (-12.50%)
time.Time.appendStrictRFC3339 439 -> 428  (-2.51%)

time [cmd/compile]
time.parseStrictRFC3339.func1 80 -> 70  (-12.50%)
time.Time.appendStrictRFC3339.func1 80 -> 70  (-12.50%)
time.Time.appendStrictRFC3339 439 -> 428  (-2.51%)

linux/arm64:

time
time.parseStrictRFC3339.func1 changed
time.Time.appendStrictRFC3339.func1 changed
time.Time.appendStrictRFC3339 416 -> 400  (-3.85%)

time [cmd/compile]
time.Time.appendStrictRFC3339 416 -> 400  (-3.85%)
time.parseStrictRFC3339.func1 changed
time.Time.appendStrictRFC3339.func1 changed

Change-Id: I0ad3b2363a9fe8c322dd05fbc13bf151a146d8cb
Reviewed-on: https://go-review.googlesource.com/c/go/+/641756
Auto-Submit: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@golang.org>

diff --git a/src/cmd/compile/internal/ssa/_gen/generic.rules b/src/cmd/compile/internal/ssa/_gen/generic.rules
index 9e2e8772c154ab4c6e25fd1fe0eb0ce0ff59994c..8ad246830e386f6d5a52d7db3063ce3a6bfdd5ed 100644 (file)
--- a/src/cmd/compile/internal/ssa/_gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/_gen/generic.rules
@@ -353,6 +353,10 @@
   (Add64 (Const64 <t> [c*d]) (Mul64 <t> (Const64 <t> [c]) x))
 (Mul32 (Const32 <t> [c]) (Add32 <t> (Const32 <t> [d]) x)) =>
   (Add32 (Const32 <t> [c*d]) (Mul32 <t> (Const32 <t> [c]) x))
+(Mul16 (Const16 <t> [c]) (Add16 <t> (Const16 <t> [d]) x)) =>
+  (Add16 (Const16 <t> [c*d]) (Mul16 <t> (Const16 <t> [c]) x))
+(Mul8 (Const8 <t> [c]) (Add8 <t> (Const8 <t> [d]) x)) =>
+  (Add8 (Const8 <t> [c*d]) (Mul8 <t> (Const8 <t> [c]) x))
 
 // Rewrite x*y ± x*z  to  x*(y±z)
 (Add(64|32|16|8) <t> (Mul(64|32|16|8) x y) (Mul(64|32|16|8) x z))

diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index 4cb287c9b7a0edd696bd96a6e3116973c76fb709..fa771bf27ddea040f9647d21f9b1ff95d776710f 100644 (file)
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -18194,6 +18194,40 @@ func rewriteValuegeneric_OpMul16(v *Value) bool {
                }
                break
        }
+       // match: (Mul16 (Const16 <t> [c]) (Add16 <t> (Const16 <t> [d]) x))
+       // result: (Add16 (Const16 <t> [c*d]) (Mul16 <t> (Const16 <t> [c]) x))
+       for {
+               for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+                       if v_0.Op != OpConst16 {
+                               continue
+                       }
+                       t := v_0.Type
+                       c := auxIntToInt16(v_0.AuxInt)
+                       if v_1.Op != OpAdd16 || v_1.Type != t {
+                               continue
+                       }
+                       _ = v_1.Args[1]
+                       v_1_0 := v_1.Args[0]
+                       v_1_1 := v_1.Args[1]
+                       for _i1 := 0; _i1 <= 1; _i1, v_1_0, v_1_1 = _i1+1, v_1_1, v_1_0 {
+                               if v_1_0.Op != OpConst16 || v_1_0.Type != t {
+                                       continue
+                               }
+                               d := auxIntToInt16(v_1_0.AuxInt)
+                               x := v_1_1
+                               v.reset(OpAdd16)
+                               v0 := b.NewValue0(v.Pos, OpConst16, t)
+                               v0.AuxInt = int16ToAuxInt(c * d)
+                               v1 := b.NewValue0(v.Pos, OpMul16, t)
+                               v2 := b.NewValue0(v.Pos, OpConst16, t)
+                               v2.AuxInt = int16ToAuxInt(c)
+                               v1.AddArg2(v2, x)
+                               v.AddArg2(v0, v1)
+                               return true
+                       }
+               }
+               break
+       }
        // match: (Mul16 (Const16 [0]) _)
        // result: (Const16 [0])
        for {
@@ -18917,6 +18951,40 @@ func rewriteValuegeneric_OpMul8(v *Value) bool {
                }
                break
        }
+       // match: (Mul8 (Const8 <t> [c]) (Add8 <t> (Const8 <t> [d]) x))
+       // result: (Add8 (Const8 <t> [c*d]) (Mul8 <t> (Const8 <t> [c]) x))
+       for {
+               for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+                       if v_0.Op != OpConst8 {
+                               continue
+                       }
+                       t := v_0.Type
+                       c := auxIntToInt8(v_0.AuxInt)
+                       if v_1.Op != OpAdd8 || v_1.Type != t {
+                               continue
+                       }
+                       _ = v_1.Args[1]
+                       v_1_0 := v_1.Args[0]
+                       v_1_1 := v_1.Args[1]
+                       for _i1 := 0; _i1 <= 1; _i1, v_1_0, v_1_1 = _i1+1, v_1_1, v_1_0 {
+                               if v_1_0.Op != OpConst8 || v_1_0.Type != t {
+                                       continue
+                               }
+                               d := auxIntToInt8(v_1_0.AuxInt)
+                               x := v_1_1
+                               v.reset(OpAdd8)
+                               v0 := b.NewValue0(v.Pos, OpConst8, t)
+                               v0.AuxInt = int8ToAuxInt(c * d)
+                               v1 := b.NewValue0(v.Pos, OpMul8, t)
+                               v2 := b.NewValue0(v.Pos, OpConst8, t)
+                               v2.AuxInt = int8ToAuxInt(c)
+                               v1.AddArg2(v2, x)
+                               v.AddArg2(v0, v1)
+                               return true
+                       }
+               }
+               break
+       }
        // match: (Mul8 (Const8 [0]) _)
        // result: (Const8 [0])
        for {