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// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssa
import (
"cmd/compile/internal/types"
"cmd/internal/src"
"testing"
)
func TestLoopConditionS390X(t *testing.T) {
// Test that a simple loop condition does not generate a conditional
// move (issue #19227).
//
// MOVDLT is generated when Less64 is lowered but should be
// optimized into an LT branch.
//
// For example, compiling the following loop:
//
// for i := 0; i < N; i++ {
// sum += 3
// }
//
// should generate assembly similar to:
// loop:
// CMP R0, R1
// BGE done
// ADD $3, R4
// ADD $1, R1
// BR loop
// done:
//
// rather than:
// loop:
// MOVD $0, R2
// MOVD $1, R3
// CMP R0, R1
// MOVDLT R2, R3
// CMPW R2, $0
// BNE done
// ADD $3, R4
// ADD $1, R1
// BR loop
// done:
//
c := testConfigS390X(t)
fun := c.Fun("entry",
Bloc("entry",
Valu("mem", OpInitMem, types.TypeMem, 0, nil),
Valu("SP", OpSP, c.config.Types.Uintptr, 0, nil),
Valu("ret", OpLocalAddr, c.config.Types.Int64.PtrTo(), 0, nil, "SP", "mem"),
Valu("N", OpArg, c.config.Types.Int64, 0, c.Frontend().Auto(src.NoXPos, c.config.Types.Int64)),
Valu("starti", OpConst64, c.config.Types.Int64, 0, nil),
Valu("startsum", OpConst64, c.config.Types.Int64, 0, nil),
Goto("b1")),
Bloc("b1",
Valu("phii", OpPhi, c.config.Types.Int64, 0, nil, "starti", "i"),
Valu("phisum", OpPhi, c.config.Types.Int64, 0, nil, "startsum", "sum"),
Valu("cmp1", OpLess64, c.config.Types.Bool, 0, nil, "phii", "N"),
If("cmp1", "b2", "b3")),
Bloc("b2",
Valu("c1", OpConst64, c.config.Types.Int64, 1, nil),
Valu("i", OpAdd64, c.config.Types.Int64, 0, nil, "phii", "c1"),
Valu("c3", OpConst64, c.config.Types.Int64, 3, nil),
Valu("sum", OpAdd64, c.config.Types.Int64, 0, nil, "phisum", "c3"),
Goto("b1")),
Bloc("b3",
Valu("retdef", OpVarDef, types.TypeMem, 0, nil, "mem"),
Valu("store", OpStore, types.TypeMem, 0, c.config.Types.Int64, "ret", "phisum", "retdef"),
Exit("store")))
CheckFunc(fun.f)
Compile(fun.f)
CheckFunc(fun.f)
checkOpcodeCounts(t, fun.f, map[Op]int{
OpS390XMOVDLT: 0,
OpS390XMOVDGT: 0,
OpS390XMOVDLE: 0,
OpS390XMOVDGE: 0,
OpS390XMOVDEQ: 0,
OpS390XMOVDNE: 0,
OpS390XCMP: 1,
OpS390XCMPWconst: 0,
})
}