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go/test/codegen/logic.go
Stefan 95c4f320d5 cmd/compile: add De Morgan's rewrite rule
Adds rules that rewrites statements such as ~P&~Q as ~(P|Q) and ~P|~Q as ~(P&Q), removing an extraneous instruction.

Change-Id: Icedb97df741680ddf9799df79df78657173aa500
GitHub-Last-Rev: f22e2350c9
GitHub-Pull-Request: golang/go#60018
Reviewed-on: https://go-review.googlesource.com/c/go/+/493175
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Stefan M <st3f4nm4d4@gmail.com>
Reviewed-by: Keith Randall <khr@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
2023-05-10 16:32:25 +00:00

42 lines
1.1 KiB
Go

// asmcheck
// Copyright 2018 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 codegen
// Test to make sure that (CMPQ (ANDQ x y) [0]) does not get rewritten to
// (TESTQ x y) if the ANDQ has other uses. If that rewrite happens, then one
// of the args of the ANDQ needs to be saved so it can be used as the arg to TESTQ.
func andWithUse(x, y int) int {
z := x & y
// amd64:`TESTQ\s(AX, AX|BX, BX|CX, CX|DX, DX|SI, SI|DI, DI|R8, R8|R9, R9|R10, R10|R11, R11|R12, R12|R13, R13|R15, R15)`
if z == 0 {
return 77
}
// use z by returning it
return z
}
// Verify (OR x (NOT y)) rewrites to (ORN x y) where supported
func ornot(x, y int) int {
// ppc64x:"ORN"
z := x | ^y
return z
}
// Verify that (OR (NOT x) (NOT y)) rewrites to (NOT (AND x y))
func orDemorgans(x, y int) int {
// amd64:"AND",-"OR"
z := ^x | ^y
return z
}
// Verify that (AND (NOT x) (NOT y)) rewrites to (NOT (OR x y))
func andDemorgans(x, y int) int {
// amd64:"OR",-"AND"
z := ^x & ^y
return z
}