From c8caad423cafcca7c39dbaf64b428aaf0e8ac80c Mon Sep 17 00:00:00 2001
From: "Paul E. Murphy" <murp@ibm.com>
Date: Mon, 18 Sep 2023 11:29:20 -0500
Subject: cmd/compile/internal/ssa: optimize (AND (MOVDconst [-1] x)) on PPC64

This sequence can show up in the lowering pass on PPC64. If it
makes it to the latelower pass, it will cause an error because
it looks like it can be turned into RLDICL, but -1 isn't an
accepted mask.

Also, print more debug info if panic is called from
encodePPC64RotateMask.

Fixes #62698

Change-Id: I0f3322e2205357abe7fc28f96e05e3f7ad65567c
Reviewed-on: https://go-review.googlesource.com/c/go/+/529195
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Run-TryBot: Paul Murphy <murp@ibm.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
---
 test/codegen/copy.go | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'test/codegen')

diff --git a/test/codegen/copy.go b/test/codegen/copy.go
index 4c4c857460..17ee8bc807 100644
--- a/test/codegen/copy.go
+++ b/test/codegen/copy.go
@@ -151,3 +151,9 @@ func ptrBothOffset() {
 	// s390x:-"BEQ",-"BNE"
 	copy(x[1:], x[2:])
 }
+
+// Verify #62698 on PPC64.
+func noMaskOnCopy(a []int, s string, x int) int {
+	// ppc64x:-"MOVD\t$-1", -"AND"
+	return a[x&^copy([]byte{}, s)]
+}
-- 
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