commit 12d5bec8c79b9841f1b25fa87ffb69b9d3cbec3b
author Matt Arsenault <Matthew.Arsenault@amd.com> Sat Jun 06 21:24:02 2020 -0400
committer Matt Arsenault <Matthew.Arsenault@amd.com> Mon Jul 20 20:53:35 2020 -0400
tree f01af65fa172a0878265e7e37b1de57f77504ced
parent 107c954c1383956cc4d98d0015d4d380fb5604d9

GlobalISel: Handle more cases in getGCDType

Try harder to find a canonical unmerge type when trying to cover the
desired target type. Handle finding a compatible unmerge type for two
vectors with different element types. This will return the largest
multiple of the source vector element that will evenly divide the
target vector type.

Also make the handling mixing scalars and vectors, and prefer the
source element type as the unmerge target type.

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 3ec04d9..4efb50c 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -252,7 +252,7 @@
                                     LLT NarrowTy, Register SrcReg) {
   LLT SrcTy = MRI.getType(SrcReg);
 
-  LLT GCDTy = getGCDType(DstTy, getGCDType(SrcTy, NarrowTy));
+  LLT GCDTy = getGCDType(getGCDType(SrcTy, NarrowTy), DstTy);
   if (SrcTy == GCDTy) {
     // If the source already evenly divides the result type, we don't need to do
     // anything.