[PATCH] D113802: [PowerPC] Fix 32bit vector insert instructions for ISA3.1

[Lei Huang via Phabricator via llvm-commits]

lei added inline comments.


================
Comment at: llvm/lib/Target/PowerPC/PPCInstrPrefix.td:2835
+// Immediate vector insert element
+let AddedComplexity = 400, Predicates = [IsISA3_1, HasVSX, IsLittleEndian] in {
+  foreach Idx = [0, 1, 2, 3] in {
----------------
nemanjai wrote:
> lei wrote:
> > nemanjai wrote:
> > > Why did you pull this out of the block above? The `Predicates` seem to be exactly the same.
> > It's because of the complexity. For vector insert double, the original pattern generated:
> > ```
> > lfd f0, 0(r5)
> > xxmrghd v2, v2, vs0
> > ```
> > seem to be better then forcing it to use VINSDRX
> > ```
> > ld r3, 0(r5)
> > li r4, 0
> > vinsdrx v2, r4, r3
> > ```
> I realize that we want to add the `AddedComplexity` but that should be orthogonal to `Predicates`
> 
> i.e.
> ```
> let Predicates = [IsISA3_1, HasVSX, IsLittleEndian] in {
>   // defs
>   let AddedComplexity = 400 in {
>     // defs with the same predicates plus added complexity
>   }
> }
> ```
You are right, I don't know why I thought it needed to be separate!  Will update that before commit!


Repository:
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  https://reviews.llvm.org/D113802/new/

https://reviews.llvm.org/D113802