Subzero, MIPS32: Intrinsic call Ctlz for i32

src/IceTargetLoweringMIPS32.cpp

Index: src/IceTargetLoweringMIPS32.cpp
diff --git a/src/IceTargetLoweringMIPS32.cpp b/src/IceTargetLoweringMIPS32.cpp
index 32656ce4ee9ba008bee7b1f7482b627942c6a49c..37ebd8e7b304c9eabc2da14da696339963d60569 100644
--- a/src/IceTargetLoweringMIPS32.cpp
+++ b/src/IceTargetLoweringMIPS32.cpp
@@ -2846,8 +2846,25 @@ void TargetMIPS32::lowerIntrinsicCall(const InstIntrinsicCall *Instr) {
     return;
   }
   case Intrinsics::Ctlz: {
-    UnimplementedLoweringError(this, Instr);
-    return;
+    auto *Src = Instr->getArg(0);
+    const Type SrcTy = Src->getType();

[Jim Stichnoth, 2016/09/22 18:18:24]

This gives an error in a MINIMAL build (make -f Makefile.standalone MINIMAL=1)
because SrcTy is only used inside an assert.

That said, I think the assert should just be removed because it is handled more
strongly in the "default:" case below.

[obucinac, 2016/09/22 18:58:16]

Maybe this would do...

+    assert(SrcTy == IceType_i32 || SrcTy == IceType_i64);
+    switch (Src->getType()) {
+    case IceType_i32: {
+      auto *T = I32Reg();
+      auto *SrcR = legalizeToReg(Src);
+      _clz(T, SrcR);
+      _mov(Dest, T);
+      break;
+    }
+    case IceType_i64: {
+      UnimplementedLoweringError(this, Instr);
+      break;
+    }
+    default:
+      llvm::report_fatal_error("Control flow should never have reached here.");
+    }
+    break;
   }
   case Intrinsics::Cttz: {
     UnimplementedLoweringError(this, Instr);