[PPC64] Fix PR20071 (fctiduz generated for targets lacking that
instruction)
PR20071 identifies a problem in PowerPC's fast-isel implementation
for floating-point conversion to integer. The fctiduz instruction
was added in Power ISA 2.06 (i.e., Power7 and later). However, this
instruction is being generated regardless of which 64-bit PowerPC
target is selected.
The intent is for fast-isel to punt to DAG selection when this
instruction is not available. This patch implements that change.
For testing purposes, the existing fast-isel-conversion.ll test adds
a RUN line for -mcpu=970 and tests for the expected code generation.
Additionally, the existing test fast-isel-conversion-p5.ll was found
to be incorrectly expecting the unavailable instruction to be
generated. I've removed these test variants since we have adequate
coverage in fast-isel-conversion.ll.
This is needed to compile clang with debug+asserts on older powerpc64
and ppc970 targets.
Requested by: jhibbits
MFC after: 3 days
96b9c77676