[PATCH] D19337: [Tail duplication] Handle source registers with subregisters

[Quentin Colombet via llvm-commits]

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Hi Krzysztof,

This looks mostly good to me. The change on how we add register class constrains seems broken to me and the test case could benefit some check lines and a run of opt -instnamer.

Cheers,
-Quentin


================
Comment at: lib/CodeGen/TailDuplicator.cpp:366
@@ -363,1 +365,3 @@
+          if (VI->second.SubReg == 0)
+            MRI->constrainRegClass(VI->second.Reg, MRI->getRegClass(Reg));
         }
----------------
Why do you check for the subreg here?
If you believe the adding constraints will not work, you should check the result of constrainRegClass and act accordingly.

================
Comment at: lib/CodeGen/TailDuplicator.cpp:877
@@ +876,3 @@
+/// described by CopyInfos. Append resulting instructions to Copies.
+void TailDuplicator::appendCopies(MachineBasicBlock *MBB,
+      SmallVectorImpl<std::pair<unsigned,RegSubRegPair>> &CopyInfos,
----------------
Use \p in front of variable names.

================
Comment at: test/CodeGen/Hexagon/tail-dup-subreg-map.ll:1
@@ +1,2 @@
+; RUN: llc -march=hexagon < %s
+; REQUIRES: asserts
----------------
FileCheck?


Repository:
  rL LLVM

http://reviews.llvm.org/D19337