test: make codegen tests work with both ABIs

Some codegen tests were written with the assumption that
arguments and results are in memory, and with a specific stack
layout. With the register ABI, the assumption is no longer true.
Adjust the tests to work with both cases.

- For tests expecting in memory arguments/results, change to use
  global variables or memory-assigned argument/results.

- Allow more registers. E.g. some tests expecting register names
  contain only letters (e.g. AX), but  it can also contain numbers
  (e.g. R10).

- Some instruction selection changes when operate on register vs.
  memory, e.g. ADDQ vs. LEAQ, MOVB vs. MOVL. Accept both.

TODO: mathbits.go and memops.go still need fix.
Change-Id: Ic5932b4b5dd3f5d30ed078d296476b641420c4c5
Reviewed-on: https://go-review.googlesource.com/c/go/+/309335
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/test/codegen/comparisons.go b/test/codegen/comparisons.go
index 719063cdc3..17dcd94ae1 100644
--- a/test/codegen/comparisons.go
+++ b/test/codegen/comparisons.go
@@ -90,9 +90,11 @@ func CompareArray6(a, b unsafe.Pointer) bool {
 
 // Test that LEAQ/ADDQconst are folded into SETx ops
 
-func CmpFold(x uint32) bool {
-	// amd64:`SETHI\t.*\(SP\)`
-	return x > 4
+var r bool
+
+func CmpFold(x uint32) {
+	// amd64:`SETHI\t.*\(SB\)`
+	r = x > 4
 }
 
 // Test that direct comparisons with memory are generated when