[PATCH] D69339: [SelectionDAG] Add support for FP_ROUND in WidenVectorOperand.

[Jay Foad via Phabricator via llvm-commits]

foad marked an inline comment as done.
foad added inline comments.


================
Comment at: llvm/test/CodeGen/AMDGPU/fptrunc.ll:34
+; FUNC-LABEL: {{^}}fptrunc_v3f64_to_v3f32:
+; GCN: v_cvt_f32_f64_e32
+; GCN: v_cvt_f32_f64_e32
----------------
arsenm wrote:
> foad wrote:
> > craig.topper wrote:
> > > Is this hitting the unrolling path rather than any of the code that creates a wider node?
> > The test definitely fails without the fix above, but I haven't looked in detail at how it is handled.
> I would expect this to hit the unroll path. v3f64 isn't legal
If I'm reading the legalize-types debug output correctly it is being widened to v4 and then split to v2:
```
Legalizing node: t33: v3f32 = fp_round t30, TargetConstant:i64<0>
Analyzing result type: v3f32
Legal result type
Analyzing operand: t30: v3f64 = extract_subvector t37, Constant:i32<0>
Widen node operand 0: t33: v3f32 = fp_round t30, TargetConstant:i64<0>

Legalizing node: t49: v4f32 = fp_round t37, TargetConstant:i64<0>
Analyzing result type: v4f32
Legal result type
Analyzing operand: t37: v4f64 = bitcast t36
Split node operand: t49: v4f32 = fp_round t37, TargetConstant:i64<0>
```
Is that a problem? Is my patch still OK?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D69339/new/

https://reviews.llvm.org/D69339