]> Cypherpunks repositories - gostls13.git/commitdiff
[dev.simd] cmd/compile, simd: add rewrite to convert logical expression trees into...
authorDavid Chase <drchase@google.com>
Thu, 9 Oct 2025 19:12:47 +0000 (15:12 -0400)
committerDavid Chase <drchase@google.com>
Fri, 24 Oct 2025 18:05:14 +0000 (11:05 -0700)
includes tests of both rewrite application and
rewrite correctness

Change-Id: I7983ccf87a8408af95bb6c447cb22f01beda9f61
Reviewed-on: https://go-review.googlesource.com/c/go/+/710697
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Junyang Shao <shaojunyang@google.com>
src/cmd/compile/internal/ssa/compile.go
src/cmd/compile/internal/ssa/rewritetern.go [new file with mode: 0644]
src/cmd/compile/internal/ssa/tern_helpers.go [new file with mode: 0644]
src/simd/genfiles.go
src/simd/internal/simd_test/simd_test.go
test/simd.go

index be1a6f158e677d3b685e548e3a7e375a26d58132..372d238a1ce78e6448b9211943db3f70c750ce9d 100644 (file)
@@ -486,6 +486,7 @@ var passes = [...]pass{
        {name: "insert resched checks", fn: insertLoopReschedChecks,
                disabled: !buildcfg.Experiment.PreemptibleLoops}, // insert resched checks in loops.
        {name: "cpufeatures", fn: cpufeatures, required: buildcfg.Experiment.SIMD, disabled: !buildcfg.Experiment.SIMD},
+       {name: "rewrite tern", fn: rewriteTern, required: false, disabled: !buildcfg.Experiment.SIMD},
        {name: "lower", fn: lower, required: true},
        {name: "addressing modes", fn: addressingModes, required: false},
        {name: "late lower", fn: lateLower, required: true},
diff --git a/src/cmd/compile/internal/ssa/rewritetern.go b/src/cmd/compile/internal/ssa/rewritetern.go
new file mode 100644 (file)
index 0000000..5493e5f
--- /dev/null
@@ -0,0 +1,292 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ssa
+
+import (
+       "fmt"
+       "internal/goarch"
+       "slices"
+)
+
+var truthTableValues [3]uint8 = [3]uint8{0b1111_0000, 0b1100_1100, 0b1010_1010}
+
+func (slop SIMDLogicalOP) String() string {
+       if slop == sloInterior {
+               return "leaf"
+       }
+       interior := ""
+       if slop&sloInterior != 0 {
+               interior = "+interior"
+       }
+       switch slop &^ sloInterior {
+       case sloAnd:
+               return "and" + interior
+       case sloXor:
+               return "xor" + interior
+       case sloOr:
+               return "or" + interior
+       case sloAndNot:
+               return "andNot" + interior
+       case sloNot:
+               return "not" + interior
+       }
+       return "wrong"
+}
+
+func rewriteTern(f *Func) {
+       if f.maxCPUFeatures == CPUNone {
+               return
+       }
+
+       arch := f.Config.Ctxt().Arch.Family
+       // TODO there are other SIMD architectures
+       if arch != goarch.AMD64 {
+               return
+       }
+
+       boolExprTrees := make(map[*Value]SIMDLogicalOP)
+
+       // Find logical-expr expression trees, including leaves.
+       // interior nodes will be marked sloInterior,
+       // root nodes will not be marked sloInterior,
+       // leaf nodes are only marked sloInterior.
+       for _, b := range f.Blocks {
+               for _, v := range b.Values {
+                       slo := classifyBooleanSIMD(v)
+                       switch slo {
+                       case sloOr,
+                               sloAndNot,
+                               sloXor,
+                               sloAnd:
+                               boolExprTrees[v.Args[1]] |= sloInterior
+                               fallthrough
+                       case sloNot:
+                               boolExprTrees[v.Args[0]] |= sloInterior
+                               boolExprTrees[v] |= slo
+                       }
+               }
+       }
+
+       // get a canonical sorted set of roots
+       var roots []*Value
+       for v, slo := range boolExprTrees {
+               if f.pass.debug > 1 {
+                       f.Warnl(v.Pos, "%s has SLO %v", v.LongString(), slo)
+               }
+
+               if slo&sloInterior == 0 && v.Block.CPUfeatures.hasFeature(CPUavx512) {
+                       roots = append(roots, v)
+               }
+       }
+       slices.SortFunc(roots, func(u, v *Value) int { return int(u.ID - v.ID) }) // IDs are small enough to not care about overflow.
+
+       // This rewrite works by iterating over the root set.
+       // For each boolean expression, it walks the expression
+       // bottom up accumulating sets of variables mentioned in
+       // subexpressions, lazy-greedily finding the largest subexpressions
+       // of 3 inputs that can be rewritten to use ternary-truth-table instructions.
+
+       // rewrite recursively attempts to replace v and v's subexpressions with
+       // ternary-logic truth-table operations, returning a set of not more than 3
+       // subexpressions within v that may be combined into a parent's replacement.
+       // V need not have the CPU features that allow a ternary-logic operation;
+       // in that case, v will not be rewritten.  Replacements also require
+       // exactly 3 different variable inputs to a boolean expression.
+       //
+       // Given the CPU feature and 3 inputs, v is replaced in the following
+       // cases:
+       //
+       // 1) v is a root
+       // 2) u = NOT(v) and u lacks the CPU feature
+       // 3) u = OP(v, w) and u lacks the CPU feature
+       // 4) u = OP(v, w) and u has more than 3 variable inputs.       var rewrite func(v *Value) [3]*Value
+       var rewrite func(v *Value) [3]*Value
+
+       // computeTT returns the truth table for a boolean expression
+       // over the variables in vars, where vars[0] varies slowest in
+       // the truth table and vars[2] varies fastest.
+       // e.g. computeTT( "and(x, or(y, not(z)))", {x,y,z} ) returns
+       // (bit 0 first) 0 0 0 0 1 0 1 1 = (reversed) 1101_0000 = 0xD0
+       //            x: 0 0 0 0 1 1 1 1
+       //            y: 0 0 1 1 0 0 1 1
+       //            z: 0 1 0 1 0 1 0 1
+       var computeTT func(v *Value, vars [3]*Value) uint8
+
+       // combine two sets of variables into one, returning ok/not
+       // if the two sets contained 3 or fewer elements.  Combine
+       // ensures that the sets of Values never contain duplicates.
+       // (Duplicates would create less-efficient code, not incorrect code.)
+       combine := func(a, b [3]*Value) ([3]*Value, bool) {
+               var c [3]*Value
+               i := 0
+               for _, v := range a {
+                       if v == nil {
+                               break
+                       }
+                       c[i] = v
+                       i++
+               }
+       bloop:
+               for _, v := range b {
+                       if v == nil {
+                               break
+                       }
+                       for _, u := range a {
+                               if v == u {
+                                       continue bloop
+                               }
+                       }
+                       if i == 3 {
+                               return [3]*Value{}, false
+                       }
+                       c[i] = v
+                       i++
+               }
+               return c, true
+       }
+
+       computeTT = func(v *Value, vars [3]*Value) uint8 {
+               i := 0
+               for ; i < len(vars); i++ {
+                       if vars[i] == v {
+                               return truthTableValues[i]
+                       }
+               }
+               slo := boolExprTrees[v] &^ sloInterior
+               a := computeTT(v.Args[0], vars)
+               switch slo {
+               case sloNot:
+                       return ^a
+               case sloAnd:
+                       return a & computeTT(v.Args[1], vars)
+               case sloXor:
+                       return a ^ computeTT(v.Args[1], vars)
+               case sloOr:
+                       return a | computeTT(v.Args[1], vars)
+               case sloAndNot:
+                       return a & ^computeTT(v.Args[1], vars)
+               }
+               panic("switch should have covered all cases, or unknown var in logical expression")
+       }
+
+       replace := func(a0 *Value, vars0 [3]*Value) {
+               imm := computeTT(a0, vars0)
+               op := ternOpForLogical(a0.Op)
+               if op == a0.Op {
+                       panic(fmt.Errorf("should have mapped away from input op, a0 is %s", a0.LongString()))
+               }
+               if f.pass.debug > 0 {
+                       f.Warnl(a0.Pos, "Rewriting %s into %v of 0b%b %v %v %v", a0.LongString(), op, imm,
+                               vars0[0], vars0[1], vars0[2])
+               }
+               a0.reset(op)
+               a0.SetArgs3(vars0[0], vars0[1], vars0[2])
+               a0.AuxInt = int64(int8(imm))
+       }
+
+       // addOne ensures the no-duplicates addition of a single value
+       // to a set that is not full.  It seems possible that a shared
+       // subexpression in tricky combination with blocks lacking the
+       // AVX512 feature might permit this.
+       addOne := func(vars [3]*Value, v *Value) [3]*Value {
+               if vars[2] != nil {
+                       panic("rewriteTern.addOne, vars[2] should be nil")
+               }
+               if v == vars[0] || v == vars[1] {
+                       return vars
+               }
+               if vars[1] == nil {
+                       vars[1] = v
+               } else {
+                       vars[2] = v
+               }
+               return vars
+       }
+
+       rewrite = func(v *Value) [3]*Value {
+               slo := boolExprTrees[v]
+               if slo == sloInterior { // leaf node, i.e., a "variable"
+                       return [3]*Value{v, nil, nil}
+               }
+               var vars [3]*Value
+               hasFeature := v.Block.CPUfeatures.hasFeature(CPUavx512)
+               if slo&sloNot == sloNot {
+                       vars = rewrite(v.Args[0])
+                       if !hasFeature {
+                               if vars[2] != nil {
+                                       replace(v.Args[0], vars)
+                                       return [3]*Value{v, nil, nil}
+                               }
+                               return vars
+                       }
+               } else {
+                       var ok bool
+                       a0, a1 := v.Args[0], v.Args[1]
+                       vars0 := rewrite(a0)
+                       vars1 := rewrite(a1)
+                       vars, ok = combine(vars0, vars1)
+
+                       if f.pass.debug > 1 {
+                               f.Warnl(a0.Pos, "combine(%v, %v) -> %v, %v", vars0, vars1, vars, ok)
+                       }
+
+                       if !(ok && v.Block.CPUfeatures.hasFeature(CPUavx512)) {
+                               // too many variables, or cannot rewrite current values.
+                               // rewrite one or both subtrees if possible
+                               if vars0[2] != nil && a0.Block.CPUfeatures.hasFeature(CPUavx512) {
+                                       replace(a0, vars0)
+                               }
+                               if vars1[2] != nil && a1.Block.CPUfeatures.hasFeature(CPUavx512) {
+                                       replace(a1, vars1)
+                               }
+
+                               // 3-element var arrays are either rewritten, or unable to be rewritten
+                               // because of the features in effect in their block.  Either way, they
+                               // are treated as a "new var" if 3 elements are present.
+
+                               if vars0[2] == nil {
+                                       if vars1[2] == nil {
+                                               // both subtrees are 2-element and were not rewritten.
+                                               //
+                                               // TODO a clever person would look at subtrees of inputs,
+                                               // e.g. rewrite
+                                               //        ((a AND b) XOR b) XOR (d  XOR (c AND d))
+                                               // to    (((a AND b) XOR b) XOR  d) XOR (c AND d)
+                                               // to v = TERNLOG(truthtable, a, b, d) XOR (c AND d)
+                                               // and return the variable set {v, c, d}
+                                               //
+                                               // But for now, just restart with a0 and a1.
+                                               return [3]*Value{a0, a1, nil}
+                                       } else {
+                                               // a1 (maybe) rewrote, a0 has room for another var
+                                               vars = addOne(vars0, a1)
+                                       }
+                               } else if vars1[2] == nil {
+                                       // a0 (maybe) rewrote, a1 has room for another var
+                                       vars = addOne(vars1, a0)
+                               } else if !ok {
+                                       // both (maybe) rewrote
+                                       // a0 and a1 are different because otherwise their variable
+                                       // sets would have combined "ok".
+                                       return [3]*Value{a0, a1, nil}
+                               }
+                               // continue with either the vars from "ok" or the updated set of vars.
+                       }
+               }
+               // if root and 3 vars and hasFeature, rewrite.
+               if slo&sloInterior == 0 && vars[2] != nil && hasFeature {
+                       replace(v, vars)
+                       return [3]*Value{v, nil, nil}
+               }
+               return vars
+       }
+
+       for _, v := range roots {
+               if f.pass.debug > 1 {
+                       f.Warnl(v.Pos, "SLO root %s", v.LongString())
+               }
+               rewrite(v)
+       }
+}
diff --git a/src/cmd/compile/internal/ssa/tern_helpers.go b/src/cmd/compile/internal/ssa/tern_helpers.go
new file mode 100644 (file)
index 0000000..3ffc980
--- /dev/null
@@ -0,0 +1,160 @@
+// Code generated by 'go run genfiles.go'; DO NOT EDIT.
+
+package ssa
+
+type SIMDLogicalOP uint8
+
+const (
+       // boolean simd operations, for reducing expression to VPTERNLOG* instructions
+       // sloInterior is set for non-root nodes in logical-op expression trees.
+       // the operations are even-numbered.
+       sloInterior SIMDLogicalOP = 1
+       sloNone     SIMDLogicalOP = 2 * iota
+       sloAnd
+       sloOr
+       sloAndNot
+       sloXor
+       sloNot
+)
+
+func classifyBooleanSIMD(v *Value) SIMDLogicalOP {
+       switch v.Op {
+       case OpAndInt8x16, OpAndInt16x8, OpAndInt32x4, OpAndInt64x2, OpAndInt8x32, OpAndInt16x16, OpAndInt32x8, OpAndInt64x4, OpAndInt8x64, OpAndInt16x32, OpAndInt32x16, OpAndInt64x8:
+               return sloAnd
+
+       case OpOrInt8x16, OpOrInt16x8, OpOrInt32x4, OpOrInt64x2, OpOrInt8x32, OpOrInt16x16, OpOrInt32x8, OpOrInt64x4, OpOrInt8x64, OpOrInt16x32, OpOrInt32x16, OpOrInt64x8:
+               return sloOr
+
+       case OpAndNotInt8x16, OpAndNotInt16x8, OpAndNotInt32x4, OpAndNotInt64x2, OpAndNotInt8x32, OpAndNotInt16x16, OpAndNotInt32x8, OpAndNotInt64x4, OpAndNotInt8x64, OpAndNotInt16x32, OpAndNotInt32x16, OpAndNotInt64x8:
+               return sloAndNot
+       case OpXorInt8x16:
+               if y := v.Args[1]; y.Op == OpEqualInt8x16 &&
+                       y.Args[0] == y.Args[1] {
+                       return sloNot
+               }
+               return sloXor
+       case OpXorInt16x8:
+               if y := v.Args[1]; y.Op == OpEqualInt16x8 &&
+                       y.Args[0] == y.Args[1] {
+                       return sloNot
+               }
+               return sloXor
+       case OpXorInt32x4:
+               if y := v.Args[1]; y.Op == OpEqualInt32x4 &&
+                       y.Args[0] == y.Args[1] {
+                       return sloNot
+               }
+               return sloXor
+       case OpXorInt64x2:
+               if y := v.Args[1]; y.Op == OpEqualInt64x2 &&
+                       y.Args[0] == y.Args[1] {
+                       return sloNot
+               }
+               return sloXor
+       case OpXorInt8x32:
+               if y := v.Args[1]; y.Op == OpEqualInt8x32 &&
+                       y.Args[0] == y.Args[1] {
+                       return sloNot
+               }
+               return sloXor
+       case OpXorInt16x16:
+               if y := v.Args[1]; y.Op == OpEqualInt16x16 &&
+                       y.Args[0] == y.Args[1] {
+                       return sloNot
+               }
+               return sloXor
+       case OpXorInt32x8:
+               if y := v.Args[1]; y.Op == OpEqualInt32x8 &&
+                       y.Args[0] == y.Args[1] {
+                       return sloNot
+               }
+               return sloXor
+       case OpXorInt64x4:
+               if y := v.Args[1]; y.Op == OpEqualInt64x4 &&
+                       y.Args[0] == y.Args[1] {
+                       return sloNot
+               }
+               return sloXor
+       case OpXorInt8x64:
+               if y := v.Args[1]; y.Op == OpEqualInt8x64 &&
+                       y.Args[0] == y.Args[1] {
+                       return sloNot
+               }
+               return sloXor
+       case OpXorInt16x32:
+               if y := v.Args[1]; y.Op == OpEqualInt16x32 &&
+                       y.Args[0] == y.Args[1] {
+                       return sloNot
+               }
+               return sloXor
+       case OpXorInt32x16:
+               if y := v.Args[1]; y.Op == OpEqualInt32x16 &&
+                       y.Args[0] == y.Args[1] {
+                       return sloNot
+               }
+               return sloXor
+       case OpXorInt64x8:
+               if y := v.Args[1]; y.Op == OpEqualInt64x8 &&
+                       y.Args[0] == y.Args[1] {
+                       return sloNot
+               }
+               return sloXor
+
+       }
+       return sloNone
+}
+
+func ternOpForLogical(op Op) Op {
+       switch op {
+       case OpAndInt8x16, OpOrInt8x16, OpXorInt8x16, OpAndNotInt8x16:
+               return OpternInt32x4
+       case OpAndUint8x16, OpOrUint8x16, OpXorUint8x16, OpAndNotUint8x16:
+               return OpternUint32x4
+       case OpAndInt16x8, OpOrInt16x8, OpXorInt16x8, OpAndNotInt16x8:
+               return OpternInt32x4
+       case OpAndUint16x8, OpOrUint16x8, OpXorUint16x8, OpAndNotUint16x8:
+               return OpternUint32x4
+       case OpAndInt32x4, OpOrInt32x4, OpXorInt32x4, OpAndNotInt32x4:
+               return OpternInt32x4
+       case OpAndUint32x4, OpOrUint32x4, OpXorUint32x4, OpAndNotUint32x4:
+               return OpternUint32x4
+       case OpAndInt64x2, OpOrInt64x2, OpXorInt64x2, OpAndNotInt64x2:
+               return OpternInt64x2
+       case OpAndUint64x2, OpOrUint64x2, OpXorUint64x2, OpAndNotUint64x2:
+               return OpternUint64x2
+       case OpAndInt8x32, OpOrInt8x32, OpXorInt8x32, OpAndNotInt8x32:
+               return OpternInt32x8
+       case OpAndUint8x32, OpOrUint8x32, OpXorUint8x32, OpAndNotUint8x32:
+               return OpternUint32x8
+       case OpAndInt16x16, OpOrInt16x16, OpXorInt16x16, OpAndNotInt16x16:
+               return OpternInt32x8
+       case OpAndUint16x16, OpOrUint16x16, OpXorUint16x16, OpAndNotUint16x16:
+               return OpternUint32x8
+       case OpAndInt32x8, OpOrInt32x8, OpXorInt32x8, OpAndNotInt32x8:
+               return OpternInt32x8
+       case OpAndUint32x8, OpOrUint32x8, OpXorUint32x8, OpAndNotUint32x8:
+               return OpternUint32x8
+       case OpAndInt64x4, OpOrInt64x4, OpXorInt64x4, OpAndNotInt64x4:
+               return OpternInt64x4
+       case OpAndUint64x4, OpOrUint64x4, OpXorUint64x4, OpAndNotUint64x4:
+               return OpternUint64x4
+       case OpAndInt8x64, OpOrInt8x64, OpXorInt8x64, OpAndNotInt8x64:
+               return OpternInt32x16
+       case OpAndUint8x64, OpOrUint8x64, OpXorUint8x64, OpAndNotUint8x64:
+               return OpternUint32x16
+       case OpAndInt16x32, OpOrInt16x32, OpXorInt16x32, OpAndNotInt16x32:
+               return OpternInt32x16
+       case OpAndUint16x32, OpOrUint16x32, OpXorUint16x32, OpAndNotUint16x32:
+               return OpternUint32x16
+       case OpAndInt32x16, OpOrInt32x16, OpXorInt32x16, OpAndNotInt32x16:
+               return OpternInt32x16
+       case OpAndUint32x16, OpOrUint32x16, OpXorUint32x16, OpAndNotUint32x16:
+               return OpternUint32x16
+       case OpAndInt64x8, OpOrInt64x8, OpXorInt64x8, OpAndNotInt64x8:
+               return OpternInt64x8
+       case OpAndUint64x8, OpOrUint64x8, OpXorUint64x8, OpAndNotUint64x8:
+               return OpternUint64x8
+
+       }
+       return op
+}
index 80234ac9f8a404b34911492f968e4bdd80a26a33..be23b127c89d21abf3cf4c080405960ec20e0ec7 100644 (file)
@@ -254,6 +254,15 @@ package simd
 `, s)
 }
 
+func ssaPrologue(s string, out io.Writer) {
+       fmt.Fprintf(out,
+               `// Code generated by '%s'; DO NOT EDIT.
+
+package ssa
+
+`, s)
+}
+
 func unsafePrologue(s string, out io.Writer) {
        fmt.Fprintf(out,
                `// Code generated by '%s'; DO NOT EDIT.
@@ -806,6 +815,7 @@ func (x {{.VType}}) String() string {
 `)
 
 const TD = "internal/simd_test/"
+const SSA = "../cmd/compile/internal/ssa/"
 
 func main() {
        sl := flag.String("sl", "slice_gen_amd64.go", "file name for slice operations")
@@ -867,6 +877,115 @@ func main() {
        if *cmh != "" {
                one(*cmh, curryTestPrologue("simd methods that compare two operands under a mask"), compareMaskedTemplate)
        }
+
+       nonTemplateRewrites(SSA+"tern_helpers.go", ssaPrologue, classifyBooleanSIMD, ternOpForLogical)
+
+}
+
+func ternOpForLogical(out io.Writer) {
+       fmt.Fprintf(out, `
+func ternOpForLogical(op Op) Op {
+       switch op {
+`)
+
+       intShapes.forAllShapes(func(seq int, t, upperT string, w, c int, out io.Writer) {
+               wt, ct := w, c
+               if wt < 32 {
+                       wt = 32
+                       ct = (w * c) / wt
+               }
+               fmt.Fprintf(out, "case OpAndInt%[1]dx%[2]d, OpOrInt%[1]dx%[2]d, OpXorInt%[1]dx%[2]d,OpAndNotInt%[1]dx%[2]d: return OpternInt%dx%d\n", w, c, wt, ct)
+               fmt.Fprintf(out, "case OpAndUint%[1]dx%[2]d, OpOrUint%[1]dx%[2]d, OpXorUint%[1]dx%[2]d,OpAndNotUint%[1]dx%[2]d: return OpternUint%dx%d\n", w, c, wt, ct)
+       }, out)
+
+       fmt.Fprintf(out, `
+       }
+       return op
+}
+`)
+
+}
+
+func classifyBooleanSIMD(out io.Writer) {
+       fmt.Fprintf(out, `
+type SIMDLogicalOP uint8
+const (
+       // boolean simd operations, for reducing expression to VPTERNLOG* instructions
+       // sloInterior is set for non-root nodes in logical-op expression trees.
+       sloInterior SIMDLogicalOP = 1
+       sloNone SIMDLogicalOP = 2 * iota
+       sloAnd
+       sloOr
+       sloAndNot
+       sloXor
+       sloNot
+)
+func classifyBooleanSIMD(v *Value) SIMDLogicalOP {
+       switch v.Op {
+               case `)
+       intShapes.forAllShapes(func(seq int, t, upperT string, w, c int, out io.Writer) {
+               op := "And"
+               if seq > 0 {
+                       fmt.Fprintf(out, ",Op%s%s%dx%d", op, upperT, w, c)
+               } else {
+                       fmt.Fprintf(out, "Op%s%s%dx%d", op, upperT, w, c)
+               }
+               seq++
+       }, out)
+
+       fmt.Fprintf(out, `:
+               return sloAnd
+
+               case `)
+       intShapes.forAllShapes(func(seq int, t, upperT string, w, c int, out io.Writer) {
+               op := "Or"
+               if seq > 0 {
+                       fmt.Fprintf(out, ",Op%s%s%dx%d", op, upperT, w, c)
+               } else {
+                       fmt.Fprintf(out, "Op%s%s%dx%d", op, upperT, w, c)
+               }
+               seq++
+       }, out)
+
+       fmt.Fprintf(out, `:
+               return sloOr
+
+               case `)
+       intShapes.forAllShapes(func(seq int, t, upperT string, w, c int, out io.Writer) {
+               op := "AndNot"
+               if seq > 0 {
+                       fmt.Fprintf(out, ",Op%s%s%dx%d", op, upperT, w, c)
+               } else {
+                       fmt.Fprintf(out, "Op%s%s%dx%d", op, upperT, w, c)
+               }
+               seq++
+       }, out)
+
+       fmt.Fprintf(out, `:
+               return sloAndNot
+`)
+
+       // "Not" is encoded as x.Xor(x.Equal(x).AsInt8x16())
+       // i.e. xor.Args[0] == x, xor.Args[1].Op == As...
+       // but AsInt8x16 is a pun/passthrough.
+
+       intShapes.forAllShapes(
+               func(seq int, t, upperT string, w, c int, out io.Writer) {
+                       fmt.Fprintf(out, "case OpXor%s%dx%d: ", upperT, w, c)
+                       fmt.Fprintf(out, `
+                               if y := v.Args[1]; y.Op == OpEqual%s%dx%d &&
+                                  y.Args[0] == y.Args[1] {
+                                               return sloNot
+                               }
+                               `, upperT, w, c)
+                       fmt.Fprintf(out, "return sloXor\n")
+               }, out)
+
+       fmt.Fprintf(out, `
+       }
+       return sloNone
+}
+`)
 }
 
 // numberLines takes a slice of bytes, and returns a string where each line
@@ -881,6 +1000,42 @@ func numberLines(data []byte) string {
        return buf.String()
 }
 
+func nonTemplateRewrites(filename string, prologue func(s string, out io.Writer), rewrites ...func(out io.Writer)) {
+       if filename == "" {
+               return
+       }
+
+       ofile := os.Stdout
+
+       if filename != "-" {
+               var err error
+               ofile, err = os.Create(filename)
+               if err != nil {
+                       fmt.Fprintf(os.Stderr, "Could not create the output file %s for the generated code, %v", filename, err)
+                       os.Exit(1)
+               }
+       }
+
+       out := new(bytes.Buffer)
+
+       prologue("go run genfiles.go", out)
+       for _, rewrite := range rewrites {
+               rewrite(out)
+       }
+
+       b, err := format.Source(out.Bytes())
+       if err != nil {
+               fmt.Fprintf(os.Stderr, "There was a problem formatting the generated code for %s, %v\n", filename, err)
+               fmt.Fprintf(os.Stderr, "%s\n", numberLines(out.Bytes()))
+               fmt.Fprintf(os.Stderr, "There was a problem formatting the generated code for %s, %v\n", filename, err)
+               os.Exit(1)
+       } else {
+               ofile.Write(b)
+               ofile.Close()
+       }
+
+}
+
 func one(filename string, prologue func(s string, out io.Writer), sats ...shapeAndTemplate) {
        if filename == "" {
                return
index 295f7bf9ce6d292fcc863f919db71ca75601ba74..c64ac0fcfd152eb8fbc26362574a20a293e34706 100644 (file)
@@ -1030,3 +1030,81 @@ func TestString(t *testing.T) {
        t.Logf("y=%s", y)
        t.Logf("z=%s", z)
 }
+
+// a returns an slice of 16 int32
+func a() []int32 {
+       return make([]int32, 16, 16)
+}
+
+// applyTo3 returns a 16-element slice of the results of
+// applying f to the respective elements of vectors x, y, and z.
+func applyTo3(x, y, z simd.Int32x16, f func(x, y, z int32) int32) []int32 {
+       ax, ay, az := a(), a(), a()
+       x.StoreSlice(ax)
+       y.StoreSlice(ay)
+       z.StoreSlice(az)
+
+       r := a()
+       for i := range r {
+               r[i] = f(ax[i], ay[i], az[i])
+       }
+       return r
+}
+
+// applyTo3 returns a 16-element slice of the results of
+// applying f to the respective elements of vectors x, y, z, and w.
+func applyTo4(x, y, z, w simd.Int32x16, f func(x, y, z, w int32) int32) []int32 {
+       ax, ay, az, aw := a(), a(), a(), a()
+       x.StoreSlice(ax)
+       y.StoreSlice(ay)
+       z.StoreSlice(az)
+       w.StoreSlice(aw)
+
+       r := make([]int32, len(ax), len(ax))
+       for i := range r {
+               r[i] = f(ax[i], ay[i], az[i], aw[i])
+       }
+       return r
+}
+
+func TestSelectTernOptInt32x16(t *testing.T) {
+       if !simd.HasAVX512() {
+               t.Skip("Test requires HasAVX512, not available on this hardware")
+               return
+       }
+       ax := []int32{0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1}
+       ay := []int32{0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1}
+       az := []int32{0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1}
+       aw := []int32{0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1}
+       am := []int32{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}
+
+       x := simd.LoadInt32x16Slice(ax)
+       y := simd.LoadInt32x16Slice(ay)
+       z := simd.LoadInt32x16Slice(az)
+       w := simd.LoadInt32x16Slice(aw)
+       m := simd.LoadInt32x16Slice(am)
+
+       foo := func(v simd.Int32x16, s []int32) {
+               r := make([]int32, 16, 16)
+               v.StoreSlice(r)
+               checkSlices[int32](t, r, s)
+       }
+
+       t0 := w.Xor(y).Xor(z)
+       ft0 := func(w, y, z int32) int32 {
+               return w ^ y ^ z
+       }
+       foo(t0, applyTo3(w, y, z, ft0))
+
+       t1 := m.And(w.Xor(y).Xor(z.Not()))
+       ft1 := func(m, w, y, z int32) int32 {
+               return m & (w ^ y ^ ^z)
+       }
+       foo(t1, applyTo4(m, w, y, z, ft1))
+
+       t2 := x.Xor(y).Xor(z).And(x.Xor(y).Xor(z.Not()))
+       ft2 := func(x, y, z int32) int32 {
+               return (x ^ y ^ z) & (x ^ y ^ ^z)
+       }
+       foo(t2, applyTo3(x, y, z, ft2))
+}
index b1695fa514deb05ac87ff0476f58fa4a922ee98a..32ed70d39a2c53178d4e6ef3ad21b7adc91daba8 100644 (file)
@@ -1,4 +1,4 @@
-// errorcheck -0 -d=ssa/cpufeatures/debug=1
+// errorcheck -0 -d=ssa/cpufeatures/debug=1,ssa/rewrite_tern/debug=1
 
 //go:build goexperiment.simd && amd64
 
@@ -95,3 +95,13 @@ b:
 c:
        println("c")
 }
+
+func ternRewrite(m, w, x, y, z simd.Int32x16) (t0, t1, t2 simd.Int32x16) {
+       if !simd.HasAVX512() { // ERROR "has features avx[+]avx2[+]avx512$"
+               return // ERROR "has features avx[+]avx2[+]avx512$" // all blocks have it because of the vector size
+       }
+       t0 = w.Xor(y).Xor(z)                            // ERROR "Rewriting.*ternInt"
+       t1 = m.And(w.Xor(y).Xor(z.Not()))               // ERROR "Rewriting.*ternInt"
+       t2 = x.Xor(y).Xor(z).And(x.Xor(y).Xor(z.Not())) // ERROR "Rewriting.*ternInt"
+       return                                          // ERROR "has features avx[+]avx2[+]avx512$"
+}