cmd/compile: update to rules on PPC64 folding bit reversal to load

In the Power10 rule to fold bit reversal into load, the MOVWZreg or
MOVHZreg (Zeroing out the upper bits of a  word or halfword) becomes
redundant since byte reverse (BR) load clears the upper bits. Hence
removing for Power10. Similarly for < Power10  cases in the rule used to
fold bit reversal into load (Bswap), the above redundant operation is removed.

Change-Id: Idb027e8b6e79b6acfb81d48a9a6cc06f8e9cd2db
Reviewed-on: https://go-review.googlesource.com/c/go/+/531377
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Jayanth Krishnamurthy <jayanth.krishnamurthy@ibm.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

diff --git a/src/cmd/compile/internal/ssa/_gen/PPC64.rules b/src/cmd/compile/internal/ssa/_gen/PPC64.rules
index 77eb553aedfc16dd1957f88972d4882a02df2077..5780260c24936f2c908fdee6afee2733edbe902c 100644 (file)
--- a/src/cmd/compile/internal/ssa/_gen/PPC64.rules
+++ b/src/cmd/compile/internal/ssa/_gen/PPC64.rules
@@ -999,7 +999,7 @@
 
 // Fold bit reversal into loads.
 (BR(W|H) x:(MOV(W|H)Zload [off] {sym} ptr mem)) && x.Uses == 1 => @x.Block (MOV(W|H)BRload (MOVDaddr <ptr.Type> [off] {sym} ptr) mem)
-(BR(W|H) x:(MOV(W|H)Zloadidx ptr idx      mem)) && x.Uses == 1 => @x.Block (MOV(W|H)Zreg (MOV(W|H)BRloadidx ptr idx mem))
+(BR(W|H) x:(MOV(W|H)Zloadidx ptr idx      mem)) && x.Uses == 1 => @x.Block (MOV(W|H)BRloadidx ptr idx mem)
 (BRD x:(MOVDload [off] {sym} ptr mem)) && x.Uses == 1 => @x.Block (MOVDBRload (MOVDaddr <ptr.Type> [off] {sym} ptr) mem)
 (BRD x:(MOVDloadidx ptr idx      mem)) && x.Uses == 1 => @x.Block (MOVDBRloadidx ptr idx mem)
 
@@ -1010,7 +1010,7 @@
 // GOPPC64<10 rules.
 // These Bswap operations should only be introduced by the memcombine pass in places where they can be folded into loads or stores.
 (Bswap(32|16) x:(MOV(W|H)Zload [off] {sym} ptr mem)) => @x.Block (MOV(W|H)BRload (MOVDaddr <ptr.Type> [off] {sym} ptr) mem)
-(Bswap(32|16) x:(MOV(W|H)Zloadidx ptr idx      mem)) => @x.Block (MOV(W|H)Zreg (MOV(W|H)BRloadidx ptr idx mem))
+(Bswap(32|16) x:(MOV(W|H)Zloadidx ptr idx      mem)) => @x.Block (MOV(W|H)BRloadidx ptr idx mem)
 (Bswap64 x:(MOVDload [off] {sym} ptr mem)) => @x.Block (MOVDBRload (MOVDaddr <ptr.Type> [off] {sym} ptr) mem)
 (Bswap64 x:(MOVDloadidx ptr idx      mem)) => @x.Block (MOVDBRloadidx ptr idx mem)
 (MOV(D|W|H)store [off] {sym} ptr (Bswap(64|32|16) val) mem) => (MOV(D|W|H)BRstore (MOVDaddr <ptr.Type> [off] {sym} ptr) val mem)

diff --git a/src/cmd/compile/internal/ssa/rewritePPC64.go b/src/cmd/compile/internal/ssa/rewritePPC64.go
index 1809b0a77bb79224a5fa41bd39d13828a3bd1255..7ec6bb4e4629d987f20a5bef8fbaeee72ffa540f 100644 (file)
--- a/src/cmd/compile/internal/ssa/rewritePPC64.go
+++ b/src/cmd/compile/internal/ssa/rewritePPC64.go
@@ -1178,7 +1178,7 @@ func rewriteValuePPC64_OpBswap16(v *Value) bool {
                return true
        }
        // match: (Bswap16 x:(MOVHZloadidx ptr idx mem))
-       // result: @x.Block (MOVHZreg (MOVHBRloadidx ptr idx mem))
+       // result: @x.Block (MOVHBRloadidx ptr idx mem)
        for {
                x := v_0
                if x.Op != OpPPC64MOVHZloadidx {
@@ -1188,11 +1188,9 @@ func rewriteValuePPC64_OpBswap16(v *Value) bool {
                ptr := x.Args[0]
                idx := x.Args[1]
                b = x.Block
-               v0 := b.NewValue0(v.Pos, OpPPC64MOVHZreg, typ.Int64)
+               v0 := b.NewValue0(v.Pos, OpPPC64MOVHBRloadidx, typ.Int16)
                v.copyOf(v0)
-               v1 := b.NewValue0(v.Pos, OpPPC64MOVHBRloadidx, typ.Int16)
-               v1.AddArg3(ptr, idx, mem)
-               v0.AddArg(v1)
+               v0.AddArg3(ptr, idx, mem)
                return true
        }
        return false
@@ -1235,7 +1233,7 @@ func rewriteValuePPC64_OpBswap32(v *Value) bool {
                return true
        }
        // match: (Bswap32 x:(MOVWZloadidx ptr idx mem))
-       // result: @x.Block (MOVWZreg (MOVWBRloadidx ptr idx mem))
+       // result: @x.Block (MOVWBRloadidx ptr idx mem)
        for {
                x := v_0
                if x.Op != OpPPC64MOVWZloadidx {
@@ -1245,11 +1243,9 @@ func rewriteValuePPC64_OpBswap32(v *Value) bool {
                ptr := x.Args[0]
                idx := x.Args[1]
                b = x.Block
-               v0 := b.NewValue0(v.Pos, OpPPC64MOVWZreg, typ.Int64)
+               v0 := b.NewValue0(v.Pos, OpPPC64MOVWBRloadidx, typ.Int32)
                v.copyOf(v0)
-               v1 := b.NewValue0(v.Pos, OpPPC64MOVWBRloadidx, typ.Int32)
-               v1.AddArg3(ptr, idx, mem)
-               v0.AddArg(v1)
+               v0.AddArg3(ptr, idx, mem)
                return true
        }
        return false
@@ -4446,7 +4442,7 @@ func rewriteValuePPC64_OpPPC64BRH(v *Value) bool {
        }
        // match: (BRH x:(MOVHZloadidx ptr idx mem))
        // cond: x.Uses == 1
-       // result: @x.Block (MOVHZreg (MOVHBRloadidx ptr idx mem))
+       // result: @x.Block (MOVHBRloadidx ptr idx mem)
        for {
                x := v_0
                if x.Op != OpPPC64MOVHZloadidx {
@@ -4459,11 +4455,9 @@ func rewriteValuePPC64_OpPPC64BRH(v *Value) bool {
                        break
                }
                b = x.Block
-               v0 := b.NewValue0(v.Pos, OpPPC64MOVHZreg, typ.Int64)
+               v0 := b.NewValue0(v.Pos, OpPPC64MOVHBRloadidx, typ.Int16)
                v.copyOf(v0)
-               v1 := b.NewValue0(v.Pos, OpPPC64MOVHBRloadidx, typ.Int16)
-               v1.AddArg3(ptr, idx, mem)
-               v0.AddArg(v1)
+               v0.AddArg3(ptr, idx, mem)
                return true
        }
        return false
@@ -4499,7 +4493,7 @@ func rewriteValuePPC64_OpPPC64BRW(v *Value) bool {
        }
        // match: (BRW x:(MOVWZloadidx ptr idx mem))
        // cond: x.Uses == 1
-       // result: @x.Block (MOVWZreg (MOVWBRloadidx ptr idx mem))
+       // result: @x.Block (MOVWBRloadidx ptr idx mem)
        for {
                x := v_0
                if x.Op != OpPPC64MOVWZloadidx {
@@ -4512,11 +4506,9 @@ func rewriteValuePPC64_OpPPC64BRW(v *Value) bool {
                        break
                }
                b = x.Block
-               v0 := b.NewValue0(v.Pos, OpPPC64MOVWZreg, typ.Int64)
+               v0 := b.NewValue0(v.Pos, OpPPC64MOVWBRloadidx, typ.Int32)
                v.copyOf(v0)
-               v1 := b.NewValue0(v.Pos, OpPPC64MOVWBRloadidx, typ.Int32)
-               v1.AddArg3(ptr, idx, mem)
-               v0.AddArg(v1)
+               v0.AddArg3(ptr, idx, mem)
                return true
        }
        return false