Skip to content

G
go
Commit fbfbf03b authored by Michael Munday's avatar Michael Munday
Browse files
Options

cmd/compile: fix Zero-to-Load forwarding rules 

Avoid using values that do not dominate the block the Zero op is in.
Should fix the SSA check builder.

The additional OffPtr ops inserted by these rules should always be
optimized away when the Load is replaced with a const zero.

Fixes #25288.

Change-Id: I4163b58e60364f77c8a206ba084073a58ca6320a
Reviewed-on: https://go-review.googlesource.com/112136
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarKeith Randall <khr@golang.org>
parent 8af0c77d
Hide whitespace changes
Inline Side-by-side
Showing with 38 additions and 20 deletions
src/cmd/compile/internal/ssa/gen/generic.rules
View file @ fbfbf03b
......@@ -575,26 +575,29 @@
(Store {t2} p2 _
mem:(Zero [n] p3 _)))
&& o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p3)
&& fe.CanSSA(t1)
&& disjoint(op, t1.Size(), p2, sizeof(t2))
-> @mem.Block (Load <t1> op mem)
-> @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p3) mem)
(Load <t1> op:(OffPtr [o1] p1)
(Store {t2} p2 _
(Store {t3} p3 _
mem:(Zero [n] p4 _))))
&& o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p4)
&& fe.CanSSA(t1)
&& disjoint(op, t1.Size(), p2, sizeof(t2))
&& disjoint(op, t1.Size(), p3, sizeof(t3))
-> @mem.Block (Load <t1> op mem)
-> @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p4) mem)
(Load <t1> op:(OffPtr [o1] p1)
(Store {t2} p2 _
(Store {t3} p3 _
(Store {t4} p4 _
mem:(Zero [n] p5 _)))))
&& o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p5)
&& fe.CanSSA(t1)
&& disjoint(op, t1.Size(), p2, sizeof(t2))
&& disjoint(op, t1.Size(), p3, sizeof(t3))
&& disjoint(op, t1.Size(), p4, sizeof(t4))
-> @mem.Block (Load <t1> op mem)
-> @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p5) mem)
(Load <t1> op:(OffPtr [o1] p1)
(Store {t2} p2 _
(Store {t3} p3 _
......@@ -602,11 +605,12 @@
(Store {t5} p5 _
mem:(Zero [n] p6 _))))))
&& o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p6)
&& fe.CanSSA(t1)
&& disjoint(op, t1.Size(), p2, sizeof(t2))
&& disjoint(op, t1.Size(), p3, sizeof(t3))
&& disjoint(op, t1.Size(), p4, sizeof(t4))
&& disjoint(op, t1.Size(), p5, sizeof(t5))
-> @mem.Block (Load <t1> op mem)
-> @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p6) mem)
// Zero to Load forwarding.
(Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
......
src/cmd/compile/internal/ssa/rewritegeneric.go
View file @ fbfbf03b
......@@ -13133,6 +13133,8 @@ func rewriteValuegeneric_OpLess8U_0(v *Value) bool {
func rewriteValuegeneric_OpLoad_0(v *Value) bool {
b := v.Block
_ = b
fe := b.Func.fe
_ = fe
// match: (Load <t1> p1 (Store {t2} p2 x _))
// cond: isSamePtr(p1, p2) && t1.Compare(x.Type) == types.CMPeq && t1.Size() == sizeof(t2)
// result: x
......@@ -13372,8 +13374,8 @@ func rewriteValuegeneric_OpLoad_0(v *Value) bool {
return true
}
// match: (Load <t1> op:(OffPtr [o1] p1) (Store {t2} p2 _ mem:(Zero [n] p3 _)))
// cond: o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p3) && disjoint(op, t1.Size(), p2, sizeof(t2))
// result: @mem.Block (Load <t1> op mem)
// cond: o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p3) && fe.CanSSA(t1) && disjoint(op, t1.Size(), p2, sizeof(t2))
// result: @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p3) mem)
for {
t1 := v.Type
_ = v.Args[1]
......@@ -13397,20 +13399,23 @@ func rewriteValuegeneric_OpLoad_0(v *Value) bool {
n := mem.AuxInt
_ = mem.Args[1]
p3 := mem.Args[0]
if !(o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p3) && disjoint(op, t1.Size(), p2, sizeof(t2))) {
if !(o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p3) && fe.CanSSA(t1) && disjoint(op, t1.Size(), p2, sizeof(t2))) {
break
}
b = mem.Block
v0 := b.NewValue0(v.Pos, OpLoad, t1)
v.reset(OpCopy)
v.AddArg(v0)
v0.AddArg(op)
v1 := b.NewValue0(v.Pos, OpOffPtr, op.Type)
v1.AuxInt = o1
v1.AddArg(p3)
v0.AddArg(v1)
v0.AddArg(mem)
return true
}
// match: (Load <t1> op:(OffPtr [o1] p1) (Store {t2} p2 _ (Store {t3} p3 _ mem:(Zero [n] p4 _))))
// cond: o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p4) && disjoint(op, t1.Size(), p2, sizeof(t2)) && disjoint(op, t1.Size(), p3, sizeof(t3))
// result: @mem.Block (Load <t1> op mem)
// cond: o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p4) && fe.CanSSA(t1) && disjoint(op, t1.Size(), p2, sizeof(t2)) && disjoint(op, t1.Size(), p3, sizeof(t3))
// result: @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p4) mem)
for {
t1 := v.Type
_ = v.Args[1]
......@@ -13441,14 +13446,17 @@ func rewriteValuegeneric_OpLoad_0(v *Value) bool {
n := mem.AuxInt
_ = mem.Args[1]
p4 := mem.Args[0]
if !(o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p4) && disjoint(op, t1.Size(), p2, sizeof(t2)) && disjoint(op, t1.Size(), p3, sizeof(t3))) {
if !(o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p4) && fe.CanSSA(t1) && disjoint(op, t1.Size(), p2, sizeof(t2)) && disjoint(op, t1.Size(), p3, sizeof(t3))) {
break
}
b = mem.Block
v0 := b.NewValue0(v.Pos, OpLoad, t1)
v.reset(OpCopy)
v.AddArg(v0)
v0.AddArg(op)
v1 := b.NewValue0(v.Pos, OpOffPtr, op.Type)
v1.AuxInt = o1
v1.AddArg(p4)
v0.AddArg(v1)
v0.AddArg(mem)
return true
}
......@@ -13460,8 +13468,8 @@ func rewriteValuegeneric_OpLoad_10(v *Value) bool {
fe := b.Func.fe
_ = fe
// match: (Load <t1> op:(OffPtr [o1] p1) (Store {t2} p2 _ (Store {t3} p3 _ (Store {t4} p4 _ mem:(Zero [n] p5 _)))))
// cond: o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p5) && disjoint(op, t1.Size(), p2, sizeof(t2)) && disjoint(op, t1.Size(), p3, sizeof(t3)) && disjoint(op, t1.Size(), p4, sizeof(t4))
// result: @mem.Block (Load <t1> op mem)
// cond: o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p5) && fe.CanSSA(t1) && disjoint(op, t1.Size(), p2, sizeof(t2)) && disjoint(op, t1.Size(), p3, sizeof(t3)) && disjoint(op, t1.Size(), p4, sizeof(t4))
// result: @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p5) mem)
for {
t1 := v.Type
_ = v.Args[1]
......@@ -13499,20 +13507,23 @@ func rewriteValuegeneric_OpLoad_10(v *Value) bool {
n := mem.AuxInt
_ = mem.Args[1]
p5 := mem.Args[0]
if !(o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p5) && disjoint(op, t1.Size(), p2, sizeof(t2)) && disjoint(op, t1.Size(), p3, sizeof(t3)) && disjoint(op, t1.Size(), p4, sizeof(t4))) {
if !(o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p5) && fe.CanSSA(t1) && disjoint(op, t1.Size(), p2, sizeof(t2)) && disjoint(op, t1.Size(), p3, sizeof(t3)) && disjoint(op, t1.Size(), p4, sizeof(t4))) {
break
}
b = mem.Block
v0 := b.NewValue0(v.Pos, OpLoad, t1)
v.reset(OpCopy)
v.AddArg(v0)
v0.AddArg(op)
v1 := b.NewValue0(v.Pos, OpOffPtr, op.Type)
v1.AuxInt = o1
v1.AddArg(p5)
v0.AddArg(v1)
v0.AddArg(mem)
return true
}
// match: (Load <t1> op:(OffPtr [o1] p1) (Store {t2} p2 _ (Store {t3} p3 _ (Store {t4} p4 _ (Store {t5} p5 _ mem:(Zero [n] p6 _))))))
// cond: o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p6) && disjoint(op, t1.Size(), p2, sizeof(t2)) && disjoint(op, t1.Size(), p3, sizeof(t3)) && disjoint(op, t1.Size(), p4, sizeof(t4)) && disjoint(op, t1.Size(), p5, sizeof(t5))
// result: @mem.Block (Load <t1> op mem)
// cond: o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p6) && fe.CanSSA(t1) && disjoint(op, t1.Size(), p2, sizeof(t2)) && disjoint(op, t1.Size(), p3, sizeof(t3)) && disjoint(op, t1.Size(), p4, sizeof(t4)) && disjoint(op, t1.Size(), p5, sizeof(t5))
// result: @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p6) mem)
for {
t1 := v.Type
_ = v.Args[1]
......@@ -13557,14 +13568,17 @@ func rewriteValuegeneric_OpLoad_10(v *Value) bool {
n := mem.AuxInt
_ = mem.Args[1]
p6 := mem.Args[0]
if !(o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p6) && disjoint(op, t1.Size(), p2, sizeof(t2)) && disjoint(op, t1.Size(), p3, sizeof(t3)) && disjoint(op, t1.Size(), p4, sizeof(t4)) && disjoint(op, t1.Size(), p5, sizeof(t5))) {
if !(o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p6) && fe.CanSSA(t1) && disjoint(op, t1.Size(), p2, sizeof(t2)) && disjoint(op, t1.Size(), p3, sizeof(t3)) && disjoint(op, t1.Size(), p4, sizeof(t4)) && disjoint(op, t1.Size(), p5, sizeof(t5))) {
break
}
b = mem.Block
v0 := b.NewValue0(v.Pos, OpLoad, t1)
v.reset(OpCopy)
v.AddArg(v0)
v0.AddArg(op)
v1 := b.NewValue0(v.Pos, OpOffPtr, op.Type)
v1.AuxInt = o1
v1.AddArg(p6)
v0.AddArg(v1)
v0.AddArg(mem)
return true
}
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7