[llvm] [AMDGPU] Make v2f64 fneg legal on gfx1251 (PR #203427)

[Changpeng Fang via llvm-commits]

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@@ -1006,7 +1014,14 @@ AMDGPULegalizerInfo::AMDGPULegalizerInfo(const GCNSubtarget &ST_,
   auto &MinNumMaxNum = getActionDefinitionsBuilder(
       {G_FMINNUM, G_FMAXNUM, G_FMINIMUMNUM, G_FMAXIMUMNUM});
 
-  if (ST.hasVOP3PInsts()) {
+  if (ST.hasPackedFP64Ops()) {
+    MinNumMaxNum.customFor(FPTypesPK16_64)
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changpeng wrote:

G_FNEG to make it work on global-isel path? 

https://github.com/llvm/llvm-project/pull/203427