Revert "cmd/compile: improve stp merging for non-sequent cases"

This reverts commit 4c63d798cb947a3cdd5a5b68f254a73d83eb288f.

Reason for revert: Causes miscompilations. See issue 75365.

Change-Id: Icd1fcfeb23d2ec524b16eb556030f43875e1c90d
Reviewed-on: https://go-review.googlesource.com/c/go/+/702455
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Mark Freeman <markfreeman@google.com>

1 files changed, 2 insertions, 19 deletions

diff --git a/test/codegen/memcombine.go b/test/codegen/memcombine.go
index 9457d15f6a..fa0e902ac2 100644
--- a/test/codegen/memcombine.go
+++ b/test/codegen/memcombine.go
@@ -1053,34 +1053,17 @@ func dwstoreF32(p *struct{ a, b float32 }, x, y float32) {
 }
 
 func dwstoreBig(p *struct{ a, b, c, d, e, f int64 }, a, b, c, d, e, f int64) {
-	// arm64:`STP\s\(R[0-9]+, R[0-9]+\), 16\(R[0-9]+\)`
+	// This is not perfect. We merge b+a, then d+e, then c and f have no pair.
 	p.c = c
-	// arm64:`STP\s\(R[0-9]+, R[0-9]+\), 32\(R[0-9]+\)`
 	p.f = f
 	// arm64:`STP\s\(R[0-9]+, R[0-9]+\), \(R[0-9]+\)`
 	p.a = a
+	// arm64:`STP\s\(R[0-9]+, R[0-9]+\), 24\(R[0-9]+\)`
 	p.e = e
 	p.d = d
 	p.b = b
 }
 
-func dwstoreUnorderedArray(p *struct{ a, b, c, d int }, a, b, c, d int) {
-	// arm64:`STP\s\(R[0-9]+, R[0-9]+\), 16\(R[0-9]+\)`
-	p.c = c
-	p.d = d
-	// arm64:`STP\s\(R[0-9]+, R[0-9]+\), \(R[0-9]+\)`
-	p.a = a
-	p.b = b
-}
-
-func dwstoreBigNil(p *struct{ i, j struct{ a, b, c int } }) {
-	// arm64:`STP\s\(ZR, ZR\), 32\(R[0-9]+\)`
-	// arm64:`STP\s\(ZR, ZR\), 16\(R[0-9]+\)`
-	p.j = struct{ a, b, c int }{}
-	// arm64:`STP\s\(ZR, ZR\), \(R[0-9]+\)`
-	p.i = struct{ a, b, c int }{}
-}
-
 func dwstoreRet() [2]int {
 	// arm64:"STP\t"
 	return [2]int{5, 6}