[PATCH] D104410: GlobalISel/Utils: Refactor constant splat match functions

[Petar Avramovic via Phabricator via llvm-commits]

Petar.Avramovic added inline comments.


================
Comment at: llvm/lib/CodeGen/GlobalISel/Utils.cpp:987
+                                                 bool AllowUndef) {
+  // Match as any constant and get APFloat from Reg. Allows nan splat matching.
+  if (auto SplatValAndReg = getAnyConstantSplat(VReg, MRI, AllowUndef))
----------------
foad wrote:
> What does "Allows nan splat matching" mean?
Splat of NaN value, if we get value as APFloat all comparisons with it are false and we cant check for splat. We check for splat using APInt and check if constant is g_fconstant with getFConstantVRegValWithLookThrough and get APFloat.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D104410/new/

https://reviews.llvm.org/D104410