http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56339
Bug #: 56339
Summary: [4.8 Regression]: Suboptimal register allocation
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Keywords: ra
Severity: normal
Priority: P3
Component: rtl-optimization
AssignedTo: [email protected]
ReportedBy: [email protected]
CC: [email protected]
Split out from PR55941.
The testcase from referred PR
--cut here--
typedef struct A { double a, b; } A;
double f(A x,double y){return x.a+y;}
--cut here--
compiles to (-O2):
f:
addsd %xmm0, %xmm2
movapd %xmm2, %xmm0
ret
gcc-4.7 generates:
f:
addsd %xmm2, %xmm0
ret
LRA does not take into account commutative operands here.
