cmd/asm: on PPC64, allow ISEL to accept a CR bit arg

Using the CR bit register arguments makes it more easy to
understand which condition and CR field is being tested when
using ISEL.

Likewise, cleanup optab setup for ISEL. ISEL should only
accept a 5 bit unsigned constant (C_U5CON), and C_ZCON
arguments are accepted by a C_U5CON optab arg.

Change-Id: I2495dbe3595dd3f16c510b3492a88133af9f7e1a
Reviewed-on: https://go-review.googlesource.com/c/go/+/402375
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Run-TryBot: Paul Murphy <murp@ibm.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

diff --git a/src/cmd/asm/internal/asm/testdata/ppc64.s b/src/cmd/asm/internal/asm/testdata/ppc64.s
index 5452668791d205522e35d9e45def10612331bbf9..8663963c64aa8ea7fc422c37a8f3819888475b57 100644 (file)
--- a/src/cmd/asm/internal/asm/testdata/ppc64.s
+++ b/src/cmd/asm/internal/asm/testdata/ppc64.s
@@ -351,11 +351,18 @@ TEXT asmtest(SB),DUPOK|NOSPLIT,$0
        CRORN CR0GT, CR0EQ, CR0SO       // 4c620b42
        CRXOR CR0GT, CR0EQ, CR0SO       // 4c620982
 
-       ISEL $1, R3, R4, R5             // 7ca3205e
        ISEL $0, R3, R4, R5             // 7ca3201e
+       ISEL $1, R3, R4, R5             // 7ca3205e
        ISEL $2, R3, R4, R5             // 7ca3209e
        ISEL $3, R3, R4, R5             // 7ca320de
        ISEL $4, R3, R4, R5             // 7ca3211e
+       ISEL $31, R3, R4, R5            // 7ca327de
+       ISEL CR0LT, R3, R4, R5          // 7ca3201e
+       ISEL CR0GT, R3, R4, R5          // 7ca3205e
+       ISEL CR0EQ, R3, R4, R5          // 7ca3209e
+       ISEL CR0SO, R3, R4, R5          // 7ca320de
+       ISEL CR1LT, R3, R4, R5          // 7ca3211e
+       ISEL CR7SO, R3, R4, R5          // 7ca327de
        POPCNTB R3, R4                  // 7c6400f4
        POPCNTW R3, R4                  // 7c6402f4
        POPCNTD R3, R4                  // 7c6403f4

diff --git a/src/cmd/internal/obj/ppc64/asm9.go b/src/cmd/internal/obj/ppc64/asm9.go
index 9ee469c6f226e2a1bd3835b7284dd6f5d1b59fd0..399e17ebabb5165ec4e2b4afb3b8e3c066d76535 100644 (file)
--- a/src/cmd/internal/obj/ppc64/asm9.go
+++ b/src/cmd/internal/obj/ppc64/asm9.go
@@ -313,8 +313,8 @@ var optab = []Optab{
        {as: AADDME, a1: C_REG, a6: C_REG, type_: 47, size: 4},
        {as: AEXTSB, a1: C_REG, a6: C_REG, type_: 48, size: 4},
        {as: AEXTSB, a6: C_REG, type_: 48, size: 4},
-       {as: AISEL, a1: C_LCON, a2: C_REG, a3: C_REG, a6: C_REG, type_: 84, size: 4},
-       {as: AISEL, a1: C_ZCON, a2: C_REG, a3: C_REG, a6: C_REG, type_: 84, size: 4},
+       {as: AISEL, a1: C_U5CON, a2: C_REG, a3: C_REG, a6: C_REG, type_: 84, size: 4},
+       {as: AISEL, a1: C_CRBIT, a2: C_REG, a3: C_REG, a6: C_REG, type_: 84, size: 4},
        {as: ANEG, a1: C_REG, a6: C_REG, type_: 47, size: 4},
        {as: ANEG, a6: C_REG, type_: 47, size: 4},
        {as: AREM, a1: C_REG, a6: C_REG, type_: 50, size: 12},
@@ -1876,9 +1876,6 @@ func buildop(ctxt *obj.Link) {
                case AFCMPO:
                        opset(AFCMPU, r0)
 
-               case AISEL:
-                       opset(AISEL, r0)
-
                case AMTFSB0:
                        opset(AMTFSB0CC, r0)
                        opset(AMTFSB1, r0)
@@ -2042,6 +2039,7 @@ func buildop(ctxt *obj.Link) {
                        ACLRLSLWI,
                        AMTVSRDD,
                        APNOP,
+                       AISEL,
                        obj.ANOP,
                        obj.ATEXT,
                        obj.AUNDEF,
@@ -3610,6 +3608,10 @@ func (c *ctxt9) asmout(p *obj.Prog, o *Optab, out []uint32) {
 
        case 84: // ISEL BC,RA,RB,RT -> isel rt,ra,rb,bc
                bc := c.vregoff(&p.From)
+               if o.a1 == C_CRBIT {
+                       // CR bit is encoded as a register, not a constant.
+                       bc = int64(p.From.Reg)
+               }
 
                // rt = To.Reg, ra = p.Reg, rb = p.From3.Reg
                o1 = AOP_ISEL(OP_ISEL, uint32(p.To.Reg), uint32(p.Reg), uint32(p.GetFrom3().Reg), uint32(bc))