https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70243
Bug ID: 70243
Summary: PowerPC V4DFmode should not use Altivec instructions
on VSX systems
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: meissner at gcc dot gnu.org
Target Milestone: ---
The traditional Altivec single precision vector floating point instructions
should not be used if the VSX instructions are available. This is due to the
fact that the Altivec instruction does not use the current rounding mode, while
the VSX instruction does.
I did a quick glance through vsx.md and altivec.md, and I believe the only
places we use the Altivec instruction by default is for 4 operand fused
multiply-add and 4 operand fused negate multiply-subtract, when the destination
operand does not overlap with the input operands.
