Avoid redundant reload of PL_op in the runloop.

hvds · nwc10 · commit 339aac22c276 · 2010-04-15T13:05:38.000+01:00
(gcc, at least, generates suboptimal code without this dirty great hint)
diff --git a/run.c b/run.c
@@ -37,7 +37,8 @@ int
 Perl_runops_standard(pTHX)
 {
     dVAR;
-    while ((PL_op = CALL_FPTR(PL_op->op_ppaddr)(aTHX))) {
+    register OP *op = PL_op;
+    while ((PL_op = op = CALL_FPTR(op->op_ppaddr)(aTHX))) {
     }
 
     TAINT_NOT;

Original file line number	Diff line number	Diff line change
`@@ -37,7 +37,8 @@ int`
`37`	`37`	`Perl_runops_standard(pTHX)`
`38`	`38`	`{`
`39`	`39`	`dVAR;`
`40`		`- while ((PL_op = CALL_FPTR(PL_op->op_ppaddr)(aTHX))) {`
	`40`	`+ register OP *op = PL_op;`
	`41`	`+ while ((PL_op = op = CALL_FPTR(op->op_ppaddr)(aTHX))) {`
`41`	`42`	`}`
`42`	`43`
`43`	`44`	`TAINT_NOT;`