http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56547
Bug #: 56547
Summary: [SH] missed opportunity for fmac with -ffast-math
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: target
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: olege...@gcc.gnu.org
Target: sh*-*-*
This one was mentioned in PR 55295:
float test (float a, float b)
{
return a * b + a;
}
compiled with -m4-single -O2 -ffast-math results in:
fldi1 fr0 ! 7 movsf_ie/4 [length = 2]
fadd fr5,fr0 ! 8 addsf3_i [length = 2]
rts ! 27 *return_i [length = 2]
fmul fr4,fr0 ! 9 mulsf3_i [length = 2]
At least on SH using fmac in this case would be better than transforming
'a * b + a' into '(1 + b) * a'. Not sure yet whether this is actually target
specific.
