[dev.ssa] cmd/compile: simplify repeated OCOM
Rewrite ^{n}x to be ^{n % 2}x. This will eventually resolve a fuzz
issue that breaks v1.5.
Updates #11352
Change-Id: I1b3f93872d06222f9ff5f6fd5580178ebaf4c003
Reviewed-on: https://go-review.googlesource.com/13110
Reviewed-by: Keith Randall <khr@golang.org>
diff --git a/src/cmd/compile/internal/gc/testdata/arith_ssa.go b/src/cmd/compile/internal/gc/testdata/arith_ssa.go
index e69212e..6341e9b 100644
--- a/src/cmd/compile/internal/gc/testdata/arith_ssa.go
+++ b/src/cmd/compile/internal/gc/testdata/arith_ssa.go
@@ -156,6 +156,21 @@
return a + 8207351403619448057 - b - 1779494519303207690 + c*8810076340510052032*d - 4465874067674546219 - e*4361839741470334295 - f + 8688847565426072650*g*8065564729145417479
}
+func testOcom() {
+ want1, want2 := int32(0x55555555), int32(-0x55555556)
+ if got1, got2 := testOcom_ssa(0x55555555, 0x55555555); want1 != got1 || want2 != got2 {
+ println("testSubqToNegq failed, wanted", want1, "and", want2,
+ "got", got1, "and", got2)
+ failed = true
+ }
+}
+
+func testOcom_ssa(a, b int32) (int32, int32) {
+ switch { // prevent inlining
+ }
+ return ^^^^a, ^^^^^b
+}
+
var failed = false
func main() {
@@ -165,6 +180,7 @@
testRegallocCVSpill()
testSubqToNegq()
testBitwiseLogic()
+ testOcom()
if failed {
panic("failed")
diff --git a/src/cmd/compile/internal/ssa/gen/generic.rules b/src/cmd/compile/internal/ssa/gen/generic.rules
index 9cc2f1b..cb6a200 100644
--- a/src/cmd/compile/internal/ssa/gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/gen/generic.rules
@@ -34,6 +34,11 @@
(Neq16 x x) -> (ConstBool {false})
(Neq8 x x) -> (ConstBool {false})
+(Com8 (Com8 x)) -> (Copy x)
+(Com16 (Com16 x)) -> (Copy x)
+(Com32 (Com32 x)) -> (Copy x)
+(Com64 (Com64 x)) -> (Copy x)
+
// tear apart slices
// TODO: anything that generates a slice needs to go in here.
(SlicePtr (Load ptr mem)) -> (Load ptr mem)
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index 17608d7..bccf81b 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -76,6 +76,82 @@
goto end4894dd7b58383fee5f8a92be08437c33
end4894dd7b58383fee5f8a92be08437c33:
;
+ case OpCom16:
+ // match: (Com16 (Com16 x))
+ // cond:
+ // result: (Copy x)
+ {
+ if v.Args[0].Op != OpCom16 {
+ goto end388d572e5a72fd87a07da5cab243ebdc
+ }
+ x := v.Args[0].Args[0]
+ v.Op = OpCopy
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v.AddArg(x)
+ return true
+ }
+ goto end388d572e5a72fd87a07da5cab243ebdc
+ end388d572e5a72fd87a07da5cab243ebdc:
+ ;
+ case OpCom32:
+ // match: (Com32 (Com32 x))
+ // cond:
+ // result: (Copy x)
+ {
+ if v.Args[0].Op != OpCom32 {
+ goto end5b2b3834acc7313649923604f685e7c5
+ }
+ x := v.Args[0].Args[0]
+ v.Op = OpCopy
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v.AddArg(x)
+ return true
+ }
+ goto end5b2b3834acc7313649923604f685e7c5
+ end5b2b3834acc7313649923604f685e7c5:
+ ;
+ case OpCom64:
+ // match: (Com64 (Com64 x))
+ // cond:
+ // result: (Copy x)
+ {
+ if v.Args[0].Op != OpCom64 {
+ goto end6d6312f25d06a327d92f028b1ce50566
+ }
+ x := v.Args[0].Args[0]
+ v.Op = OpCopy
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v.AddArg(x)
+ return true
+ }
+ goto end6d6312f25d06a327d92f028b1ce50566
+ end6d6312f25d06a327d92f028b1ce50566:
+ ;
+ case OpCom8:
+ // match: (Com8 (Com8 x))
+ // cond:
+ // result: (Copy x)
+ {
+ if v.Args[0].Op != OpCom8 {
+ goto end70cbd85c4b8e82c170dba7c23f8bc0f3
+ }
+ x := v.Args[0].Args[0]
+ v.Op = OpCopy
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v.AddArg(x)
+ return true
+ }
+ goto end70cbd85c4b8e82c170dba7c23f8bc0f3
+ end70cbd85c4b8e82c170dba7c23f8bc0f3:
+ ;
case OpConstString:
// match: (ConstString {s})
// cond:
