[Bug target/65240] [5 Regression] ICE (insn does not satisfy its constraints) on powerpc64le-linux-gnu

[meissner at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65240

--- Comment #12 from Michael Meissner <meissner at gcc dot gnu.org> ---
Created attachment 34952
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34952&action=edit
Initial patch to paper over the problem

This patch papers over the problem.  As I mentioned before this is an
interaction between -ffast-math and -mupper-regs-df.  I was able to replicate
it for both power7 and power8 targets, and turning off either -ffast-math or
-mupper-regs-df allowed the problem to compile.

I suspect that the logic in easy_fp_constant to keep the CONST_DOUBLE around to
reload time is no longer needed, and that reciprocal approximation does not
need the constant in the RTL, but uses the register notes.