Use RegisterInfo::regsOverlaps instead of checking aliases

This is both less code and faster since it doesn't have to expand all
the sub & superreg sets. NFCI.

1 files changed, 3 insertions, 9 deletions

diff --git a/llvm/lib/CodeGen/CallingConvLower.cpp b/llvm/lib/CodeGen/CallingConvLower.cpp
index c9246f6e8754..d51b3547565d 100644
--- a/llvm/lib/CodeGen/CallingConvLower.cpp
+++ b/llvm/lib/CodeGen/CallingConvLower.cpp
@@ -72,15 +72,9 @@ bool CCState::IsShadowAllocatedReg(MCRegister Reg) const {
   if (!isAllocated(Reg))
     return false;
 
-  for (auto const &ValAssign : Locs) {
-    if (ValAssign.isRegLoc()) {
-      for (MCRegAliasIterator AI(ValAssign.getLocReg(), &TRI, true);
-           AI.isValid(); ++AI) {
-        if (*AI == Reg)
-          return false;
-      }
-    }
-  }
+  for (auto const &ValAssign : Locs)
+    if (ValAssign.isRegLoc() && TRI.regsOverlap(ValAssign.getLocReg(), Reg))
+      return false;
   return true;
 }