qbe

commit 2bbfcf61b38edfe3c347cd270380e5117454c0cf
parent 0437e97a1bb126cfa1974dad7b5479fa4b407f46
Author: Michael Forney <mforney@mforney.org>
Date:   Tue,  6 Jul 2021 21:31:34 -0700

copy: consider identity element for more instructions

udiv %x, 1 == %x, and for each of sub, or, xor, sar, shr, and shl,
<op> %x, 0 == %x.

Diffstat:
M
copy.c
 | 
8
+++++++-

1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/copy.c b/copy.c
@@ -27,10 +27,16 @@ iscopy(Ins *i, Ref r, Fn *fn)
 	case Ocopy:
 		return 1;
 	case Omul:
-		return iscon(i->arg[1], 1, fn);
 	case Odiv:
+	case Oudiv:
 		return iscon(i->arg[1], 1, fn);
 	case Oadd:
+	case Osub:
+	case Oor:
+	case Oxor:
+	case Osar:
+	case Oshl:
+	case Oshr:
 		return iscon(i->arg[1], 0, fn);
 	default:
 		break;