qbe

commit 15cee065a57ed7c7f5272bb6b60f7518121ec4da
parent a7fb69fd782470e20553e90e97fcc13f9218e2ae
Author: Quentin Carbonneaux <quentin.carbonneaux@yale.edu>
Date:   Fri,  8 Apr 2016 09:40:07 -0400

simplify a buggy test

I found it by compiling -O2 and seeing the ABI code
fail.  Further investigation revealed GCC trimmed
away the last iteration of the loop because I was
accessing the third element of an array of size two.
This is undefined behavior, so GCC "proved" that the
last iteration was never run.

Diffstat:
M
sysv.c
 | 
2
+-

1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sysv.c b/sysv.c
@@ -92,7 +92,7 @@ retr(Ref reg[2], AClass *aret)
 
 	nr[0] = nr[1] = 0;
 	ca = 0;
-	for (n=0; aret->cls[n]>=0 && n<2; n++) {
+	for (n=0; (uint)n*8<aret->size; n++) {
 		k = KBASE(aret->cls[n]);
 		reg[n] = TMP(retreg[k][nr[k]++]);
 		ca += 1 << (2 * k);