Revert "Revert r339977: [GISel]: Add Opcodes for a few LLVM Intrinsics"

This reverts commit 7debc334e6421bb5251ef8f18e97166dfc7dd787.

I missed updating legalizer-info-validation.mir as I had assertions
turned off in my build and that specific test requires asserts. Fixed it
now.

llvm-svn: 340197
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 81bebdf..c58b2ef 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -861,6 +861,16 @@
         .addDef(getOrCreateVReg(CI))
         .addUse(getOrCreateVReg(*CI.getArgOperand(0)));
     return true;
+  case Intrinsic::trunc:
+    MIRBuilder.buildInstr(TargetOpcode::G_INTRINSIC_TRUNC)
+        .addDef(getOrCreateVReg(CI))
+        .addUse(getOrCreateVReg(*CI.getArgOperand(0)));
+    return true;
+  case Intrinsic::round:
+    MIRBuilder.buildInstr(TargetOpcode::G_INTRINSIC_ROUND)
+        .addDef(getOrCreateVReg(CI))
+        .addUse(getOrCreateVReg(*CI.getArgOperand(0)));
+    return true;
   case Intrinsic::fma:
     MIRBuilder.buildInstr(TargetOpcode::G_FMA)
         .addDef(getOrCreateVReg(CI))