cmd/compile/internal, runtime: use NOOP for hardware NOPs on loong64

The canonical LoongArch NOP instruction form is "andi r0, r0, 0", as described in the LoongArch Reference Manual Volume 1, Section 2.2.1.10. We currently use NOR instead, which may or may not change anything (e.g. performance on less capable micro-architectures) but is deviation from upstream standards nevertheless. Fix them to use the explicit hardware NOP which happens to be supported as `NOOP`. Change-Id: I0a799a1da959e9c3b582feb88202df2bab0ab23a Reviewed-on: https://go-review.googlesource.com/c/go/+/475615 Reviewed-by: abner chenc <[email protected]> TryBot-Result: Gopher Robot <[email protected]> Run-TryBot: Wayne Zuo <[email protected]> Reviewed-by: Ian Lance Taylor <[email protected]> Reviewed-by: Cherry Mui <[email protected]>
Evalle777 · Mar 15, 2023 · 7789966 · 7789966
1 parent b5c8ae9
commit 7789966
Show file tree

Hide file tree

Showing 2 changed files with 3 additions and 7 deletions.
diff --git a/src/cmd/compile/internal/loong64/ggen.go b/src/cmd/compile/internal/loong64/ggen.go
@@ -50,10 +50,6 @@ func zerorange(pp *objw.Progs, p *obj.Prog, off, cnt int64, _ *uint32) *obj.Prog
 }
 
 func ginsnop(pp *objw.Progs) *obj.Prog {
-	p := pp.Prog(loong64.ANOR)
-	p.From.Type = obj.TYPE_REG
-	p.From.Reg = loong64.REG_R0
-	p.To.Type = obj.TYPE_REG
-	p.To.Reg = loong64.REG_R0
+	p := pp.Prog(loong64.ANOOP)
 	return p
 }
diff --git a/src/runtime/asm_loong64.s b/src/runtime/asm_loong64.s
@@ -618,10 +618,10 @@ TEXT _cgo_topofstack(SB),NOSPLIT,$16
 // The top-most function running on a goroutine
 // returns to goexit+PCQuantum.
 TEXT runtime·goexit(SB),NOSPLIT|NOFRAME|TOPFRAME,$0-0
-	NOR	R0, R0	// NOP
+	NOOP
 	JAL	runtime·goexit1(SB)	// does not return
 	// traceback from goexit1 must hit code range of goexit
-	NOR	R0, R0	// NOP
+	NOOP
 
 TEXT ·checkASM(SB),NOSPLIT,$0-1
 	MOVW	$1, R19