[mips][micromips] Make getPointerRegClass() result depend on the instruction.

Summary:
Previously, it returned the GPR16MMRegClass for all instructions which was
incorrect for instructions like lwsp/lwgp and unnecesarily restricted the
permitted registers for instructions like lw32.

This fixes quite a few of the -verify-machineinstrs errors reported in PR27458.
I've only added -verify-machineinstrs to one test in this change since I
understand there is a plan to enable the verifier by default.

Reviewers: hvarga, zbuljan, zoran.jovanovic, sdardis

Subscribers: dsanders, llvm-commits, sdardis

Differential Revision: http://reviews.llvm.org/D19873

llvm-svn: 268918

1 files changed, 12 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/MipsRegisterInfo.h b/llvm/lib/Target/Mips/MipsRegisterInfo.h
index 286fe8e3255..32f835e8310 100644
--- a/llvm/lib/Target/Mips/MipsRegisterInfo.h
+++ b/llvm/lib/Target/Mips/MipsRegisterInfo.h
@@ -23,6 +23,18 @@
 namespace llvm {
 class MipsRegisterInfo : public MipsGenRegisterInfo {
 public:
+  enum class MipsPtrClass {
+    /// The default register class for integer values.
+    Default = 0,
+    /// The subset of registers permitted in certain microMIPS instructions
+    /// such as lw16.
+    GPR16MM = 1,
+    /// The stack pointer only.
+    StackPointer = 2,
+    /// The global pointer only.
+    GlobalPointer = 3,
+  };
+
   MipsRegisterInfo();
 
   /// Get PIC indirect call register