commit 2cbbc6e87c4b565a54c9bb85e34d464acb608f16
author Matt Arsenault <Matthew.Arsenault@amd.com> Tue Jan 05 23:25:18 2021 -0500
committer Matt Arsenault <Matthew.Arsenault@amd.com> Thu Jan 07 17:40:34 2021 -0500
tree f8fd03213bfc951b00a9dbd048a1d011ba0abfe9
parent c01202a7efdd73fed280755184762b0ef8a5b78a

GlobalISel: Fail legalization on narrowing extload below memory size

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 7b346a1..61b2611 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -962,10 +962,15 @@
 
     Register TmpReg = MRI.createGenericVirtualRegister(NarrowTy);
     auto &MMO = **MI.memoperands_begin();
-    if (MMO.getSizeInBits() == NarrowSize) {
+    unsigned MemSize = MMO.getSizeInBits();
+
+    if (MemSize == NarrowSize) {
       MIRBuilder.buildLoad(TmpReg, PtrReg, MMO);
-    } else {
+    } else if (MemSize < NarrowSize) {
       MIRBuilder.buildLoadInstr(MI.getOpcode(), TmpReg, PtrReg, MMO);
+    } else if (MemSize > NarrowSize) {
+      // FIXME: Need to split the load.
+      return UnableToLegalize;
     }
 
     if (ZExt)