cmd/compile: use MakeResult in empty MakeSlice elimination

This gets eliminated by thoses rules above:
  // for rewriting results of some late-expanded rewrites (below)
  (SelectN [0] (MakeResult x ___)) => x
  (SelectN [1] (MakeResult x y ___)) => y
  (SelectN [2] (MakeResult x y z ___)) => z

Fixes #58161

Change-Id: I4fbfd52c72c06b6b3db906bd9910b6dbb7fe8975
Reviewed-on: https://go-review.googlesource.com/c/go/+/463846
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>

diff --git a/src/cmd/compile/internal/ssa/_gen/generic.rules b/src/cmd/compile/internal/ssa/_gen/generic.rules
index 0cbde1ee45b195eb8013ad1df2eb812db9cd560e..10da571988e5f2ce256d3b26153d5c0b2eb8881b 100644 (file)
--- a/src/cmd/compile/internal/ssa/_gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/_gen/generic.rules
@@ -2077,15 +2077,9 @@
   => (Zero {types.Types[types.TUINT8]} [int64(c)] sptr mem)
 
 // Recognise make([]T, 0) and replace it with a pointer to the zerobase
-(SelectN [0] call:(StaticLECall _ (Const(64|32) [0]) (Const(64|32) [0]) _))
-       && isSameCall(call.Aux, "runtime.makeslice")
-       && clobberIfDead(call)
-       => (Addr {ir.Syms.Zerobase} (SB))
-
-(SelectN [1] call:(StaticLECall _ (Const(64|32) [0]) (Const(64|32) [0]) mem))
-       && isSameCall(call.Aux, "runtime.makeslice")
-       && clobberIfDead(call)
-       => mem
+(StaticLECall {callAux} _ (Const(64|32) [0]) (Const(64|32) [0]) mem)
+       && isSameCall(callAux, "runtime.makeslice")
+       => (MakeResult (Addr <v.Type.FieldType(0)> {ir.Syms.Zerobase} (SB)) mem)
 
 // Evaluate constant address comparisons.
 (EqPtr  x x) => (ConstBool [true])

diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index 5917d45505ddfab895bd251d5467b1cda76503e2..b81d0931190c1cdb5e4604fe24c91bf0dfed963e 100644 (file)
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -26380,7 +26380,6 @@ func rewriteValuegeneric_OpSelectN(v *Value) bool {
        v_0 := v.Args[0]
        b := v.Block
        config := b.Func.Config
-       typ := &b.Func.Config.Types
        // match: (SelectN [0] (MakeResult x ___))
        // result: x
        for {
@@ -26467,104 +26466,6 @@ func rewriteValuegeneric_OpSelectN(v *Value) bool {
                v.AddArg2(sptr, mem)
                return true
        }
-       // match: (SelectN [0] call:(StaticLECall _ (Const64 [0]) (Const64 [0]) _))
-       // cond: isSameCall(call.Aux, "runtime.makeslice") && clobberIfDead(call)
-       // result: (Addr {ir.Syms.Zerobase} (SB))
-       for {
-               if auxIntToInt64(v.AuxInt) != 0 {
-                       break
-               }
-               call := v_0
-               if call.Op != OpStaticLECall || len(call.Args) != 4 {
-                       break
-               }
-               _ = call.Args[2]
-               call_1 := call.Args[1]
-               if call_1.Op != OpConst64 || auxIntToInt64(call_1.AuxInt) != 0 {
-                       break
-               }
-               call_2 := call.Args[2]
-               if call_2.Op != OpConst64 || auxIntToInt64(call_2.AuxInt) != 0 || !(isSameCall(call.Aux, "runtime.makeslice") && clobberIfDead(call)) {
-                       break
-               }
-               v.reset(OpAddr)
-               v.Aux = symToAux(ir.Syms.Zerobase)
-               v0 := b.NewValue0(v.Pos, OpSB, typ.Uintptr)
-               v.AddArg(v0)
-               return true
-       }
-       // match: (SelectN [0] call:(StaticLECall _ (Const32 [0]) (Const32 [0]) _))
-       // cond: isSameCall(call.Aux, "runtime.makeslice") && clobberIfDead(call)
-       // result: (Addr {ir.Syms.Zerobase} (SB))
-       for {
-               if auxIntToInt64(v.AuxInt) != 0 {
-                       break
-               }
-               call := v_0
-               if call.Op != OpStaticLECall || len(call.Args) != 4 {
-                       break
-               }
-               _ = call.Args[2]
-               call_1 := call.Args[1]
-               if call_1.Op != OpConst32 || auxIntToInt32(call_1.AuxInt) != 0 {
-                       break
-               }
-               call_2 := call.Args[2]
-               if call_2.Op != OpConst32 || auxIntToInt32(call_2.AuxInt) != 0 || !(isSameCall(call.Aux, "runtime.makeslice") && clobberIfDead(call)) {
-                       break
-               }
-               v.reset(OpAddr)
-               v.Aux = symToAux(ir.Syms.Zerobase)
-               v0 := b.NewValue0(v.Pos, OpSB, typ.Uintptr)
-               v.AddArg(v0)
-               return true
-       }
-       // match: (SelectN [1] call:(StaticLECall _ (Const64 [0]) (Const64 [0]) mem))
-       // cond: isSameCall(call.Aux, "runtime.makeslice") && clobberIfDead(call)
-       // result: mem
-       for {
-               if auxIntToInt64(v.AuxInt) != 1 {
-                       break
-               }
-               call := v_0
-               if call.Op != OpStaticLECall || len(call.Args) != 4 {
-                       break
-               }
-               mem := call.Args[3]
-               call_1 := call.Args[1]
-               if call_1.Op != OpConst64 || auxIntToInt64(call_1.AuxInt) != 0 {
-                       break
-               }
-               call_2 := call.Args[2]
-               if call_2.Op != OpConst64 || auxIntToInt64(call_2.AuxInt) != 0 || !(isSameCall(call.Aux, "runtime.makeslice") && clobberIfDead(call)) {
-                       break
-               }
-               v.copyOf(mem)
-               return true
-       }
-       // match: (SelectN [1] call:(StaticLECall _ (Const32 [0]) (Const32 [0]) mem))
-       // cond: isSameCall(call.Aux, "runtime.makeslice") && clobberIfDead(call)
-       // result: mem
-       for {
-               if auxIntToInt64(v.AuxInt) != 1 {
-                       break
-               }
-               call := v_0
-               if call.Op != OpStaticLECall || len(call.Args) != 4 {
-                       break
-               }
-               mem := call.Args[3]
-               call_1 := call.Args[1]
-               if call_1.Op != OpConst32 || auxIntToInt32(call_1.AuxInt) != 0 {
-                       break
-               }
-               call_2 := call.Args[2]
-               if call_2.Op != OpConst32 || auxIntToInt32(call_2.AuxInt) != 0 || !(isSameCall(call.Aux, "runtime.makeslice") && clobberIfDead(call)) {
-                       break
-               }
-               v.copyOf(mem)
-               return true
-       }
        // match: (SelectN [0] call:(StaticCall {sym} s1:(Store _ (Const64 [sz]) s2:(Store _ src s3:(Store {t} _ dst mem)))))
        // cond: sz >= 0 && isSameCall(sym, "runtime.memmove") && s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1 && isInlinableMemmove(dst, src, int64(sz), config) && clobber(s1, s2, s3, call)
        // result: (Move {types.Types[types.TUINT8]} [int64(sz)] dst src mem)
@@ -27463,6 +27364,56 @@ func rewriteValuegeneric_OpStaticLECall(v *Value) bool {
                v.AddArg2(v0, mem)
                return true
        }
+       // match: (StaticLECall {callAux} _ (Const64 [0]) (Const64 [0]) mem)
+       // cond: isSameCall(callAux, "runtime.makeslice")
+       // result: (MakeResult (Addr <v.Type.FieldType(0)> {ir.Syms.Zerobase} (SB)) mem)
+       for {
+               if len(v.Args) != 4 {
+                       break
+               }
+               callAux := auxToCall(v.Aux)
+               mem := v.Args[3]
+               v_1 := v.Args[1]
+               if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != 0 {
+                       break
+               }
+               v_2 := v.Args[2]
+               if v_2.Op != OpConst64 || auxIntToInt64(v_2.AuxInt) != 0 || !(isSameCall(callAux, "runtime.makeslice")) {
+                       break
+               }
+               v.reset(OpMakeResult)
+               v0 := b.NewValue0(v.Pos, OpAddr, v.Type.FieldType(0))
+               v0.Aux = symToAux(ir.Syms.Zerobase)
+               v1 := b.NewValue0(v.Pos, OpSB, typ.Uintptr)
+               v0.AddArg(v1)
+               v.AddArg2(v0, mem)
+               return true
+       }
+       // match: (StaticLECall {callAux} _ (Const32 [0]) (Const32 [0]) mem)
+       // cond: isSameCall(callAux, "runtime.makeslice")
+       // result: (MakeResult (Addr <v.Type.FieldType(0)> {ir.Syms.Zerobase} (SB)) mem)
+       for {
+               if len(v.Args) != 4 {
+                       break
+               }
+               callAux := auxToCall(v.Aux)
+               mem := v.Args[3]
+               v_1 := v.Args[1]
+               if v_1.Op != OpConst32 || auxIntToInt32(v_1.AuxInt) != 0 {
+                       break
+               }
+               v_2 := v.Args[2]
+               if v_2.Op != OpConst32 || auxIntToInt32(v_2.AuxInt) != 0 || !(isSameCall(callAux, "runtime.makeslice")) {
+                       break
+               }
+               v.reset(OpMakeResult)
+               v0 := b.NewValue0(v.Pos, OpAddr, v.Type.FieldType(0))
+               v0.Aux = symToAux(ir.Syms.Zerobase)
+               v1 := b.NewValue0(v.Pos, OpSB, typ.Uintptr)
+               v0.AddArg(v1)
+               v.AddArg2(v0, mem)
+               return true
+       }
        return false
 }
 func rewriteValuegeneric_OpStore(v *Value) bool {

diff --git a/test/fixedbugs/issue58161.go b/test/fixedbugs/issue58161.go
new file mode 100644 (file)
index 0000000..33113f6
--- /dev/null
+++ b/test/fixedbugs/issue58161.go
@@ -0,0 +1,15 @@
+// compile -d=ssa/check/seed=1
+
+// Copyright 2023 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 main
+
+func F[G int]() int {
+       return len(make([]int, copy([]G{}, []G{})))
+}
+
+func main() {
+       F[int]()
+}