commit e75afc9acf9b6de511c0c90b8e8a06364de46e3e
author Matt Arsenault <Matthew.Arsenault@amd.com> Tue Jul 28 10:15:42 2020 -0400
committer Matt Arsenault <Matthew.Arsenault@amd.com> Thu Sep 24 15:19:51 2020 -0400
tree 4b35dc1600a0de35263a8fb0b09e7579235a562b
parent 55bb1ba0fdd3c97d163f8115f818eafe11814623

GlobalISel: Use unmerge when copying wide vectors to result registers

Avoid using G_EXTRACT and move towards a more consistent vector
legalization strategy.

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 0004223..33596af 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -387,7 +387,14 @@
   }
 
   if (LCMTy.isVector()) {
-    MIRBuilder.buildExtract(DstReg, Remerge, 0);
+    unsigned NumDefs = LCMTy.getSizeInBits() / DstTy.getSizeInBits();
+    SmallVector<Register, 8> UnmergeDefs(NumDefs);
+    UnmergeDefs[0] = DstReg;
+    for (unsigned I = 1; I != NumDefs; ++I)
+      UnmergeDefs[I] = MRI.createGenericVirtualRegister(DstTy);
+
+    MIRBuilder.buildUnmerge(UnmergeDefs,
+                            MIRBuilder.buildMerge(LCMTy, RemergeRegs));
     return;
   }