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cmd/compile/internal/ssa: fix PPC64 shift codegen regression

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CL 621357 introduced new generic lowering rules which caused
several shift related codegen test failures.

Add new rules to fix the test regressions, and cleanup tests
which are changed but not regressed. Some CLRLSLDI tests are
removed as they are no test CLRLSLDI rules.

Fixes #70003

Change-Id: I1ecc5a7e63ab709a4a0cebf11fa078d5cf164034
Reviewed-on: https://go-review.googlesource.com/c/go/+/622236
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This commit is contained in:
Paul E. Murphy 2024-10-24 09:08:47 -05:00 committed by Paul Murphy
parent 2a98a1849f
commit 1846dd5a31
4 changed files with 120 additions and 7 deletions
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5
src/cmd/compile/internal/ssa/_gen/PPC64.rules
View File

@ -150,14 +150,19 @@
(ANDconst [m] (SRWconst x [s])) && mergePPC64RShiftMask(m,s,32) == 0 => (MOVDconst [0])
(ANDconst [m] (SRWconst x [s])) && mergePPC64AndSrwi(m,s) != 0 => (RLWINM [mergePPC64AndSrwi(m,s)] x)
(ANDconst [m] (SRDconst x [s])) && mergePPC64AndSrdi(m,s) != 0 => (RLWINM [mergePPC64AndSrdi(m,s)] x)
(AND (MOVDconst [m]) (SRWconst x [s])) && mergePPC64RShiftMask(m,s,32) == 0 => (MOVDconst [0])
(AND (MOVDconst [m]) (SRWconst x [s])) && mergePPC64AndSrwi(m,s) != 0 => (RLWINM [mergePPC64AndSrwi(m,s)] x)
(AND (MOVDconst [m]) (SRDconst x [s])) && mergePPC64AndSrdi(m,s) != 0 => (RLWINM [mergePPC64AndSrdi(m,s)] x)
(SRWconst (ANDconst [m] x) [s]) && mergePPC64RShiftMask(m>>uint(s),s,32) == 0 => (MOVDconst [0])
(SRWconst (ANDconst [m] x) [s]) && mergePPC64AndSrwi(m>>uint(s),s) != 0 => (RLWINM [mergePPC64AndSrwi(m>>uint(s),s)] x)
(SRWconst (AND (MOVDconst [m]) x) [s]) && mergePPC64RShiftMask(m>>uint(s),s,32) == 0 => (MOVDconst [0])
(SRWconst (AND (MOVDconst [m]) x) [s]) && mergePPC64AndSrwi(m>>uint(s),s) != 0 => (RLWINM [mergePPC64AndSrwi(m>>uint(s),s)] x)
(ANDconst [m] (SLDconst x [s])) && mergePPC64AndSldi(m,s) != 0 => (RLWINM [mergePPC64AndSldi(m,s)] x)
(AND (MOVDconst [m]) (SLDconst x [s])) && mergePPC64AndSldi(m,s) != 0 => (RLWINM [mergePPC64AndSldi(m,s)] x)
// Merge shift right + shift left and clear left (e.g for a table lookup)
(CLRLSLDI [c] (SRWconst [s] x)) && mergePPC64ClrlsldiSrw(int64(c),s) != 0 => (RLWINM [mergePPC64ClrlsldiSrw(int64(c),s)] x)
(CLRLSLDI [c] (SRDconst [s] x)) && mergePPC64ClrlsldiSrd(int64(c),s) != 0 => (RLWINM [mergePPC64ClrlsldiSrd(int64(c),s)] x)

30
src/cmd/compile/internal/ssa/rewrite.go
View File

@ -1580,6 +1580,36 @@ func mergePPC64AndSrwi(m, s int64) int64 {
return encodePPC64RotateMask((32-s)&31, mask, 32)
}
// Combine (ANDconst [m] (SRDconst [s])) into (RLWINM [y]) or return 0
func mergePPC64AndSrdi(m, s int64) int64 {
mask := mergePPC64RShiftMask(m, s, 64)
// Verify the rotate and mask result only uses the lower 32 bits.
rv := bits.RotateLeft64(0xFFFFFFFF00000000, -int(s))
if rv&uint64(mask) != 0 {
return 0
}
if !isPPC64WordRotateMask(mask) {
return 0
}
return encodePPC64RotateMask((32-s)&31, mask, 32)
}
// Combine (ANDconst [m] (SLDconst [s])) into (RLWINM [y]) or return 0
func mergePPC64AndSldi(m, s int64) int64 {
mask := -1 << s & m
// Verify the rotate and mask result only uses the lower 32 bits.
rv := bits.RotateLeft64(0xFFFFFFFF00000000, int(s))
if rv&uint64(mask) != 0 {
return 0
}
if !isPPC64WordRotateMask(mask) {
return 0
}
return encodePPC64RotateMask(s&31, mask, 32)
}
// Test if a word shift right feeding into a CLRLSLDI can be merged into RLWINM.
// Return the encoded RLWINM constant, or 0 if they cannot be merged.
func mergePPC64ClrlsldiSrw(sld, srw int64) int64 {

84
src/cmd/compile/internal/ssa/rewritePPC64.go
View File

@ -4292,6 +4292,54 @@ func rewriteValuePPC64_OpPPC64AND(v *Value) bool {
}
break
}
// match: (AND (MOVDconst [m]) (SRDconst x [s]))
// cond: mergePPC64AndSrdi(m,s) != 0
// result: (RLWINM [mergePPC64AndSrdi(m,s)] x)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpPPC64MOVDconst {
continue
}
m := auxIntToInt64(v_0.AuxInt)
if v_1.Op != OpPPC64SRDconst {
continue
}
s := auxIntToInt64(v_1.AuxInt)
x := v_1.Args[0]
if !(mergePPC64AndSrdi(m, s) != 0) {
continue
}
v.reset(OpPPC64RLWINM)
v.AuxInt = int64ToAuxInt(mergePPC64AndSrdi(m, s))
v.AddArg(x)
return true
}
break
}
// match: (AND (MOVDconst [m]) (SLDconst x [s]))
// cond: mergePPC64AndSldi(m,s) != 0
// result: (RLWINM [mergePPC64AndSldi(m,s)] x)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpPPC64MOVDconst {
continue
}
m := auxIntToInt64(v_0.AuxInt)
if v_1.Op != OpPPC64SLDconst {
continue
}
s := auxIntToInt64(v_1.AuxInt)
x := v_1.Args[0]
if !(mergePPC64AndSldi(m, s) != 0) {
continue
}
v.reset(OpPPC64RLWINM)
v.AuxInt = int64ToAuxInt(mergePPC64AndSldi(m, s))
v.AddArg(x)
return true
}
break
}
// match: (AND x (NOR y y))
// result: (ANDN x y)
for {
@ -4510,6 +4558,42 @@ func rewriteValuePPC64_OpPPC64ANDconst(v *Value) bool {
v.AddArg(x)
return true
}
// match: (ANDconst [m] (SRDconst x [s]))
// cond: mergePPC64AndSrdi(m,s) != 0
// result: (RLWINM [mergePPC64AndSrdi(m,s)] x)
for {
m := auxIntToInt64(v.AuxInt)
if v_0.Op != OpPPC64SRDconst {
break
}
s := auxIntToInt64(v_0.AuxInt)
x := v_0.Args[0]
if !(mergePPC64AndSrdi(m, s) != 0) {
break
}
v.reset(OpPPC64RLWINM)
v.AuxInt = int64ToAuxInt(mergePPC64AndSrdi(m, s))
v.AddArg(x)
return true
}
// match: (ANDconst [m] (SLDconst x [s]))
// cond: mergePPC64AndSldi(m,s) != 0
// result: (RLWINM [mergePPC64AndSldi(m,s)] x)
for {
m := auxIntToInt64(v.AuxInt)
if v_0.Op != OpPPC64SLDconst {
break
}
s := auxIntToInt64(v_0.AuxInt)
x := v_0.Args[0]
if !(mergePPC64AndSldi(m, s) != 0) {
break
}
v.reset(OpPPC64RLWINM)
v.AuxInt = int64ToAuxInt(mergePPC64AndSldi(m, s))
v.AddArg(x)
return true
}
// match: (ANDconst [c] (ANDconst [d] x))
// result: (ANDconst [c&d] x)
for {

8
test/codegen/shift.go
View File

@ -462,12 +462,6 @@ func checkMergedShifts64(a [256]uint32, b [256]uint64, c [256]byte, v uint64) {
a[2] = a[v>>25&0x7F]
// ppc64x: -"CLRLSLDI", "RLWNM\t[$]3, R[0-9]+, [$]29, [$]29, R[0-9]+"
a[3] = a[(v>>31)&0x01]
// ppc64x: "SRD", "CLRLSLDI", -"RLWNM"
a[4] = a[(v>>30)&0x07]
// ppc64x: "SRD", "CLRLSLDI", -"RLWNM"
a[5] = a[(v>>32)&0x01]
// ppc64x: "SRD", "CLRLSLDI", -"RLWNM"
a[6] = a[(v>>34)&0x03]
// ppc64x: -"CLRLSLDI", "RLWNM\t[$]12, R[0-9]+, [$]21, [$]28, R[0-9]+"
b[0] = b[uint8(v>>23)]
// ppc64x: -"CLRLSLDI", "RLWNM\t[$]15, R[0-9]+, [$]21, [$]28, R[0-9]+"
@ -476,7 +470,7 @@ func checkMergedShifts64(a [256]uint32, b [256]uint64, c [256]byte, v uint64) {
b[2] = b[((uint64((uint32(v) >> 21)) & 0x3f) << 4)]
// ppc64x: "RLWNM\t[$]11, R[0-9]+, [$]10, [$]15"
c[0] = c[((v>>5)&0x3F)<<16]
// ppc64x: "RLWNM\t[$]0, R[0-9]+, [$]19, [$]24"
// ppc64x: "ANDCC\t[$]8064,"
c[1] = c[((v>>7)&0x3F)<<7]
}