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cmd/compile: on PPC64, fix sign/zero extension when masking 

(ANDCCconst [y] (MOV.*reg x)) should only be merged when zero
extending. Otherwise, sign bits are lost on negative values.

(ANDCCconst [0xFF] (MOVBreg x)) should be simplified to a zero
extension of x. Likewise for the MOVHreg variant.

Fixes #61297

Change-Id: I04e4fd7dc6a826e870681f37506620d48393698b
Reviewed-on: https://go-review.googlesource.com/c/go/+/508775
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Paul Murphy <murp@ibm.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
This commit is contained in:
Paul E. Murphy 2023-07-11 09:07:43 -05:00 committed by Paul Murphy
parent af8f94e3c5
commit 5e4000ad7f
3 changed files with 37 additions and 70 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
src/cmd/compile/internal/ssa/_gen/PPC64.rules
View File

@ -588,16 +588,16 @@
// small and of zero-extend => either zero-extend or small and
(Select0 (ANDCCconst [c] y:(MOVBZreg _))) && c&0xFF == 0xFF => y
(Select0 (ANDCCconst [0xFF] y:(MOVBreg _))) => y
(Select0 (ANDCCconst [0xFF] (MOVBreg x))) => (MOVBZreg x)
(Select0 (ANDCCconst [c] y:(MOVHZreg _))) && c&0xFFFF == 0xFFFF => y
(Select0 (ANDCCconst [0xFFFF] y:(MOVHreg _))) => y
(Select0 (ANDCCconst [0xFFFF] (MOVHreg x))) => (MOVHZreg x)
(AND (MOVDconst [c]) y:(MOVWZreg _)) && c&0xFFFFFFFF == 0xFFFFFFFF => y
(AND (MOVDconst [0xFFFFFFFF]) y:(MOVWreg x)) => (MOVWZreg x)
// normal case
(Select0 (ANDCCconst [c] (MOV(B|BZ)reg x))) => (Select0 (ANDCCconst [c&0xFF] x))
(Select0 (ANDCCconst [c] (MOV(H|HZ)reg x))) => (Select0 (ANDCCconst [c&0xFFFF] x))
(Select0 (ANDCCconst [c] (MOV(W|WZ)reg x))) => (Select0 (ANDCCconst [c&0xFFFFFFFF] x))
(Select0 (ANDCCconst [c] (MOVBZreg x))) => (Select0 (ANDCCconst [c&0xFF] x))
(Select0 (ANDCCconst [c] (MOVHZreg x))) => (Select0 (ANDCCconst [c&0xFFFF] x))
(Select0 (ANDCCconst [c] (MOVWZreg x))) => (Select0 (ANDCCconst [c&0xFFFFFFFF] x))
// Eliminate unnecessary sign/zero extend following right shift
(MOV(B|H|W)Zreg (SRWconst [c] (MOVBZreg x))) => (SRWconst [c] (MOVBZreg x))

77
src/cmd/compile/internal/ssa/rewritePPC64.go
View File

@ -14410,17 +14410,19 @@ func rewriteValuePPC64_OpSelect0(v *Value) bool {
v.copyOf(y)
return true
}
// match: (Select0 (ANDCCconst [0xFF] y:(MOVBreg _)))
// result: y
// match: (Select0 (ANDCCconst [0xFF] (MOVBreg x)))
// result: (MOVBZreg x)
for {
if v_0.Op != OpPPC64ANDCCconst || auxIntToInt64(v_0.AuxInt) != 0xFF {
break
}
y := v_0.Args[0]
if y.Op != OpPPC64MOVBreg {
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpPPC64MOVBreg {
break
}
v.copyOf(y)
x := v_0_0.Args[0]
v.reset(OpPPC64MOVBZreg)
v.AddArg(x)
return true
}
// match: (Select0 (ANDCCconst [c] y:(MOVHZreg _)))
@ -14438,36 +14440,19 @@ func rewriteValuePPC64_OpSelect0(v *Value) bool {
v.copyOf(y)
return true
}
// match: (Select0 (ANDCCconst [0xFFFF] y:(MOVHreg _)))
// result: y
// match: (Select0 (ANDCCconst [0xFFFF] (MOVHreg x)))
// result: (MOVHZreg x)
for {
if v_0.Op != OpPPC64ANDCCconst || auxIntToInt64(v_0.AuxInt) != 0xFFFF {
break
}
y := v_0.Args[0]
if y.Op != OpPPC64MOVHreg {
break
}
v.copyOf(y)
return true
}
// match: (Select0 (ANDCCconst [c] (MOVBreg x)))
// result: (Select0 (ANDCCconst [c&0xFF] x))
for {
if v_0.Op != OpPPC64ANDCCconst {
break
}
c := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpPPC64MOVBreg {
if v_0_0.Op != OpPPC64MOVHreg {
break
}
x := v_0_0.Args[0]
v.reset(OpSelect0)
v0 := b.NewValue0(v.Pos, OpPPC64ANDCCconst, types.NewTuple(typ.Int, types.TypeFlags))
v0.AuxInt = int64ToAuxInt(c & 0xFF)
v0.AddArg(x)
v.AddArg(v0)
v.reset(OpPPC64MOVHZreg)
v.AddArg(x)
return true
}
// match: (Select0 (ANDCCconst [c] (MOVBZreg x)))
@ -14489,25 +14474,6 @@ func rewriteValuePPC64_OpSelect0(v *Value) bool {
v.AddArg(v0)
return true
}
// match: (Select0 (ANDCCconst [c] (MOVHreg x)))
// result: (Select0 (ANDCCconst [c&0xFFFF] x))
for {
if v_0.Op != OpPPC64ANDCCconst {
break
}
c := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpPPC64MOVHreg {
break
}
x := v_0_0.Args[0]
v.reset(OpSelect0)
v0 := b.NewValue0(v.Pos, OpPPC64ANDCCconst, types.NewTuple(typ.Int, types.TypeFlags))
v0.AuxInt = int64ToAuxInt(c & 0xFFFF)
v0.AddArg(x)
v.AddArg(v0)
return true
}
// match: (Select0 (ANDCCconst [c] (MOVHZreg x)))
// result: (Select0 (ANDCCconst [c&0xFFFF] x))
for {
@ -14527,25 +14493,6 @@ func rewriteValuePPC64_OpSelect0(v *Value) bool {
v.AddArg(v0)
return true
}
// match: (Select0 (ANDCCconst [c] (MOVWreg x)))
// result: (Select0 (ANDCCconst [c&0xFFFFFFFF] x))
for {
if v_0.Op != OpPPC64ANDCCconst {
break
}
c := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpPPC64MOVWreg {
break
}
x := v_0_0.Args[0]
v.reset(OpSelect0)
v0 := b.NewValue0(v.Pos, OpPPC64ANDCCconst, types.NewTuple(typ.Int, types.TypeFlags))
v0.AuxInt = int64ToAuxInt(c & 0xFFFFFFFF)
v0.AddArg(x)
v.AddArg(v0)
return true
}
// match: (Select0 (ANDCCconst [c] (MOVWZreg x)))
// result: (Select0 (ANDCCconst [c&0xFFFFFFFF] x))
for {

20
test/codegen/bits.go
View File

@ -374,3 +374,23 @@ func foldConstOutOfRange(a uint64) uint64 {
// arm64: "MOVD\t[$]19088744",-"ADD\t[$]19088744"
return a + 0x1234568
}
// Verify sign-extended values are not zero-extended under a bit mask (#61297)
func signextendAndMask8to64(a int8) (s, z uint64) {
// ppc64x: "MOVB", "ANDCC\t[$]1015,"
s = uint64(a) & 0x3F7
// ppc64x: -"MOVB", "ANDCC\t[$]247,"
z = uint64(uint8(a)) & 0x3F7
return
}
// Verify zero-extended values are not sign-extended under a bit mask (#61297)
func zeroextendAndMask8to64(a int8, b int16) (x, y uint64) {
// ppc64x: -"MOVB\t", -"ANDCC", "MOVBZ"
x = uint64(a) & 0xFF
// ppc64x: -"MOVH\t", -"ANDCC", "MOVHZ"
y = uint64(b) & 0xFFFF
return
}