cmd/compile/internal/ssa: combine more const stores

We already combine const stores up-to MOVQstoreconst.
Combine 2 64-bit stores of const zero into 1 sse store of 128-bit zero.

Shaves significant (>1%) amount of code from go tool:
/localdisk/itocar/golang/bin/go 10334877
go_old 10388125 [53248 bytes]

global text (code) = 51041 bytes (1.343944%)
read-only data = 663 bytes (0.039617%)
Total difference 51704 bytes (0.873981%)

Change-Id: I7bc40968023c3a69f379b10fbb433cdb11364f1b
Reviewed-on: https://go-review.googlesource.com/56250
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Giovanni Bajo <rasky@develer.com>
Reviewed-by: Keith Randall <khr@golang.org>

diff --git a/src/cmd/compile/internal/gc/asm_test.go b/src/cmd/compile/internal/gc/asm_test.go
index 23b70ae41d089d8db2f28b3321e68da43d768f0f..d3e56230bbb10f4fa369e10250f7741066235d4c 100644 (file)
--- a/src/cmd/compile/internal/gc/asm_test.go
+++ b/src/cmd/compile/internal/gc/asm_test.go
@@ -362,7 +362,7 @@ var linuxAMD64Tests = []*asmTest{
                        *t = T1{}
                }
                `,
-               []string{"\tMOVQ\t\\$0, \\(.*\\)", "\tMOVQ\t\\$0, 8\\(.*\\)", "\tMOVQ\t\\$0, 16\\(.*\\)"},
+               []string{"\tXORPS\tX., X", "\tMOVUPS\tX., \\(.*\\)", "\tMOVQ\t\\$0, 16\\(.*\\)"},
        },
        // SSA-able composite literal initialization. Issue 18872.
        {
@@ -387,7 +387,7 @@ var linuxAMD64Tests = []*asmTest{
                        *t = T2{}
                }
                `,
-               []string{"\tMOVQ\t\\$0, \\(.*\\)", "\tMOVQ\t\\$0, 8\\(.*\\)", "\tMOVQ\t\\$0, 16\\(.*\\)", "\tCALL\truntime\\.writebarrierptr\\(SB\\)"},
+               []string{"\tXORPS\tX., X", "\tMOVUPS\tX., \\(.*\\)", "\tMOVQ\t\\$0, 16\\(.*\\)", "\tCALL\truntime\\.writebarrierptr\\(SB\\)"},
        },
        // Rotate tests
        {

diff --git a/src/cmd/compile/internal/ssa/gen/AMD64.rules b/src/cmd/compile/internal/ssa/gen/AMD64.rules
index 2f38a7d5cc97849979445993ce056f8f577eca03..c31c7ced0295a5f1b4cb08ad2f03558dbe3cd973 100644 (file)
--- a/src/cmd/compile/internal/ssa/gen/AMD64.rules
+++ b/src/cmd/compile/internal/ssa/gen/AMD64.rules
@@ -2204,6 +2204,13 @@
   && ValAndOff(a).Off() + 4 == ValAndOff(c).Off()
   && clobber(x)
   -> (MOVQstore [ValAndOff(a).Off()] {s} p (MOVQconst [ValAndOff(a).Val()&0xffffffff | ValAndOff(c).Val()<<32]) mem)
+(MOVQstoreconst [c] {s} p x:(MOVQstoreconst [c2] {s} p mem))
+  && x.Uses == 1
+  && ValAndOff(c2).Off() + 8 == ValAndOff(c).Off()
+  && ValAndOff(c).Val() == 0
+  && ValAndOff(c2).Val() == 0
+  && clobber(x)
+  -> (MOVOstore [ValAndOff(c2).Off()] {s} p (MOVOconst [0]) mem)
 
 (MOVBstoreconstidx1 [c] {s} p i x:(MOVBstoreconstidx1 [a] {s} p i mem))
   && x.Uses == 1

diff --git a/src/cmd/compile/internal/ssa/rewriteAMD64.go b/src/cmd/compile/internal/ssa/rewriteAMD64.go
index 437ca36064a8fdd9a16925fc13f2b23e38827c7f..4ce6415ba55f852c148f3c5b7c099b9f866b0695 100644 (file)
--- a/src/cmd/compile/internal/ssa/rewriteAMD64.go
+++ b/src/cmd/compile/internal/ssa/rewriteAMD64.go
@@ -9009,6 +9009,8 @@ func rewriteValueAMD64_OpAMD64MOVQstore_0(v *Value) bool {
        return false
 }
 func rewriteValueAMD64_OpAMD64MOVQstoreconst_0(v *Value) bool {
+       b := v.Block
+       _ = b
        // match: (MOVQstoreconst [sc] {s} (ADDQconst [off] ptr) mem)
        // cond: ValAndOff(sc).canAdd(off)
        // result: (MOVQstoreconst [ValAndOff(sc).add(off)] {s} ptr mem)
@@ -9137,6 +9139,40 @@ func rewriteValueAMD64_OpAMD64MOVQstoreconst_0(v *Value) bool {
                v.AddArg(mem)
                return true
        }
+       // match: (MOVQstoreconst [c] {s} p x:(MOVQstoreconst [c2] {s} p mem))
+       // cond: x.Uses == 1   && ValAndOff(c2).Off() + 8 == ValAndOff(c).Off()   && ValAndOff(c).Val() == 0   && ValAndOff(c2).Val() == 0   && clobber(x)
+       // result: (MOVOstore [ValAndOff(c2).Off()] {s} p (MOVOconst [0]) mem)
+       for {
+               c := v.AuxInt
+               s := v.Aux
+               _ = v.Args[1]
+               p := v.Args[0]
+               x := v.Args[1]
+               if x.Op != OpAMD64MOVQstoreconst {
+                       break
+               }
+               c2 := x.AuxInt
+               if x.Aux != s {
+                       break
+               }
+               _ = x.Args[1]
+               if p != x.Args[0] {
+                       break
+               }
+               mem := x.Args[1]
+               if !(x.Uses == 1 && ValAndOff(c2).Off()+8 == ValAndOff(c).Off() && ValAndOff(c).Val() == 0 && ValAndOff(c2).Val() == 0 && clobber(x)) {
+                       break
+               }
+               v.reset(OpAMD64MOVOstore)
+               v.AuxInt = ValAndOff(c2).Off()
+               v.Aux = s
+               v.AddArg(p)
+               v0 := b.NewValue0(v.Pos, OpAMD64MOVOconst, types.TypeInt128)
+               v0.AuxInt = 0
+               v.AddArg(v0)
+               v.AddArg(mem)
+               return true
+       }
        // match: (MOVQstoreconst [sc] {sym1} (LEAL [off] {sym2} ptr) mem)
        // cond: canMergeSym(sym1, sym2) && ValAndOff(sc).canAdd(off)
        // result: (MOVQstoreconst [ValAndOff(sc).add(off)] {mergeSym(sym1, sym2)} ptr mem)