[llvm] [AMDGPU] Use `v_cvt_pk_*` instructions for i16_f32 saturated conversions (PR #202680)

[Jay Foad via llvm-commits]

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@@ -3139,3 +3139,49 @@ defm V_DOT8_U32_U4  : VOP3P_Real_gfx10_gfx11_gfx12_gfx13<0x19>;
 
 defm V_DOT4_I32_I8  : VOP3P_Real_gfx10 <0x16>;
 defm V_DOT8_I32_I4  : VOP3P_Real_gfx10 <0x18>;
+
+//===----------------------------------------------------------------------===//
+// GFX11+ Patterns
+//===----------------------------------------------------------------------===//
+
+// Packed f32 -> i16 saturated conversion.
+multiclass CvtPkF32ToI16Pat<SDPatternOperator dagOp, Instruction inst> {
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jayfoad wrote:

I don't quite understand what cases the 3 defs in this multiclass are supposed to handle. Is this strategy copied from somewhere else?

https://github.com/llvm/llvm-project/pull/202680