[SubZero] Handle relocatable constants for MIPS

src/IceTargetLoweringMIPS32.cpp

Index: src/IceTargetLoweringMIPS32.cpp
diff --git a/src/IceTargetLoweringMIPS32.cpp b/src/IceTargetLoweringMIPS32.cpp
index 331f1ed4c99b6a82b3c3682f1a40810004cf6baa..798813dd92ca7aa68186ab8aab49d0cc6db0d530 100644
--- a/src/IceTargetLoweringMIPS32.cpp
+++ b/src/IceTargetLoweringMIPS32.cpp
@@ -4847,10 +4847,11 @@ Operand *TargetMIPS32::legalize(Operand *From, LegalMask Allowed,
         return From;
     }
     if (auto *C = llvm::dyn_cast<ConstantRelocatable>(From)) {
-      (void)C;
-      // TODO(reed kotler): complete this case for proper implementation
+      // TODO(jaydeep.patil): Handle ST_Nonsfi case.

[Jim Stichnoth, 2016/10/16 14:44:43]

See my comment in
https://codereview.chromium.org/2085303002/diff/1/Makefile.standalone#newcode413
.

In short, nonsfi doesn't need support in MIPS.  It was added experimentally in
x86 to support another group here, but that group has moved on from Subzero, so
MIPS really only needs the native and sandboxed models.

[jaydeep.patil, 2016/10/17 04:05:02]

Done.

       Variable *Reg = makeReg(Ty, RegNum);
-      Context.insert<InstFakeDef>(Reg);
+      Variable *TReg = makeReg(Ty, RegNum);
+      _lui(TReg, C, RO_Hi);
+      _addiu(Reg, TReg, C, RO_Lo);
       return Reg;
     } else if (auto *C32 = llvm::dyn_cast<ConstantInteger32>(From)) {
       const uint32_t Value = C32->getValue();