On Fri, Oct 02, 2015 at 02:04:48PM -0500, Peter Bergner wrote:
> PR67808 exposes a problem with the constraints in the *extenddftf2_internal
> pattern, in that it allows TFmode operands to occupy Altivec registers
> which they are not allowed to do. Reload was able to work around the
> problem, but LRA is more pedantic and it caused it to go into an infinite
> spill loop until it ICEd. The following patch from Mike changes the TFmode
> output operand to use the "d" constraint instead of "ws". It also allows
> using the "ws" constraint for the two input operands, since that is allowed
> for DFmode operands.
>
> This passed bootstraps (with reload on by default and lra on by default)
> and shows no testsuite regressions. Is this ok for trunk?
>
> The bug is also present in the FSF 5 branch (4.9 is ok), is this ok for
> that too, assuming my bootstrap/regtesting there are clean?
The following patch backports the fix to GCC 5.x. There were no regressions in
doing the bootstrap/make check on both a big endian power7 system and a little
endian power8 system. Is it ok to apply the patch to the gcc-5 branch?
2015-10-20 Michael Meissner <meiss...@linux.vnet.ibm.com>
Back port from trunk:
2015-10-05 Michael Meissner <meiss...@linux.vnet.ibm.com>
Peter Bergner <berg...@vnet.ibm.com>
PR target/67808
* config/rs6000/rs6000.md (extenddftf2): In the expander, only
allow registers, but provide insns for the combiner to create for
loads from memory. Separate VSX code from non-VSX code. For
non-VSX code, combine extenddftf2_fprs into extenddftf2 and rename
externaldftf2_internal to externaldftf2_fprs. Reorder constraints
so that registers come before memory operations. Drop support from
converting DFmode to TFmode, if the DFmode value is in a GPR
register.
(extenddftf2_fprs): Likewise.
(extenddftf2_internal): Likewise.
(extenddftf2_vsx): Likewise.
(extendsftf2): In the expander, only allow registers, but provide
insns for the combiner to create for stores and loads.
--
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meiss...@linux.vnet.ibm.com, phone: +1 (978) 899-4797
