[Intrinsic] Signed Fixed Point Multiplication Intrinsic

Add an intrinsic that takes 2 signed integers with the scale of them provided
as the third argument and performs fixed point multiplication on them.

This is a part of implementing fixed point arithmetic in clang where some of
the more complex operations will be implemented as intrinsics.

Differential Revision: https://reviews.llvm.org/D54719

llvm-svn: 348912

1 files changed, 18 insertions, 0 deletions

diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 40f73c9f1a4..a31f7cddf6e 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -4541,6 +4541,24 @@ void Verifier::visitIntrinsicCallSite(Intrinsic::ID ID, CallSite CS) {
            "of ints");
     break;
   }
+  case Intrinsic::smul_fix: {
+    Value *Op1 = CS.getArgOperand(0);
+    Value *Op2 = CS.getArgOperand(1);
+    Assert(Op1->getType()->isIntOrIntVectorTy(),
+           "first operand of smul_fix must be an int type or vector "
+           "of ints");
+    Assert(Op2->getType()->isIntOrIntVectorTy(),
+           "second operand of smul_fix must be an int type or vector "
+           "of ints");
+
+    auto *Op3 = dyn_cast<ConstantInt>(CS.getArgOperand(2));
+    Assert(Op3, "third argument of smul_fix must be a constant integer");
+    Assert(Op3->getType()->getBitWidth() <= 32,
+           "third argument of smul_fix must fit within 32 bits");
+    Assert(Op3->getZExtValue() < Op1->getType()->getScalarSizeInBits(),
+           "the scale of smul_fix must be less than the width of the operands");
+    break;
+  }
   };
 }