qbe

commit 7ce4d334e54433f7e67d91baa9edb25adb26975b
parent d37db3970f06e46d1ea9b55084e065e799b09576
Author: Quentin Carbonneaux <quentin.carbonneaux@yale.edu>
Date:   Tue, 11 Aug 2015 19:49:52 -0400

add a small size optimization to emit

Diffstat:
M
lisc/emit.c
 | 
9
+++++++++

1 file changed, 9 insertions(+), 0 deletions(-)
diff --git a/lisc/emit.c b/lisc/emit.c
@@ -141,6 +141,7 @@ eins(Ins i, Fn *fn, FILE *f)
 		[OStoreb - OStorel] = "b",
 	};
 	int r;
+	int64_t val;
 
 	switch (i.op) {
 	case OAdd:
@@ -159,6 +160,14 @@ eins(Ins i, Fn *fn, FILE *f)
 		eop(otoa[i.op], i.arg[1], i.to, fn, f);
 		break;
 	case OCopy:
+		if (i.to.val < EAX && rtype(i.arg[0]) == RCon) {
+			val = fn->con[i.arg[0].val].val;
+			if (0 <= val && val <= UINT32_MAX) {
+				fprintf(f, "\tmov $%"PRId64", %%%s\n",
+					val, rsub[i.to.val][SWord]);
+				break;
+			}
+		}
 		if (!req(i.arg[0], i.to))
 			eop("mov", i.arg[0], i.to, fn, f);
 		break;