The sign-extending Alpha instructions like addl are sometimes not used. I
don't know whether the SEE pass is supposed to affect this, or whether it
is something a combiner pass should do...
#include <stdlib.h>
/* gcc 4.2.0 20060506:
negq a0,v0
cmovge a0,a0,v0
sextl v0,v0
optimal:
negl a0,v0
cmovge a0,a0,v0 */
int f5(int x) {
return abs(x);
}
/* gcc 4.2.0 20060506:
s4addq a0,a0,v0
s4addq v0,v0,v0
s8addq v0,a0,v0
s8addq v0,a0,v0 #
sextl v0,v0 # can be combined to s8addl v0,a0,v0 */
int64_t f23(int16_t x) {
return 1609 * x;
}
/* gcc 4.2.0 20060506:
ldah t0,-32768
xor a0,t0,v0
addq v0,t0,v0 #
sextl v0,v0 # can be combined to addl v0,t0,v0 */
unsigned f49(unsigned val) {
return (val ^ 0x80000000) - 0x80000000;
}
--
Summary: sign-extending Alpha instructions not exploited
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: falk at debian dot org
GCC build triplet: alphaev68-unknown-linux-gnu
GCC host triplet: alphaev68-unknown-linux-gnu
GCC target triplet: alphaev68-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27468
