[Scalarizer] Add scalarizer support for smul.fix.sat

Summary:
Handle smul.fix.sat in the scalarizer. This is done by
adding smul.fix.sat to the set of "isTriviallyVectorizable"
intrinsics.

The addition of smul.fix.sat in isTriviallyVectorizable and
hasVectorInstrinsicScalarOpd can also be seen as a preparation
to be able to use hasVectorInstrinsicScalarOpd in ConstantFolding.

Reviewers: rengolin, RKSimon, dblaikie

Reviewed By: rengolin

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63704

llvm-svn: 364177

1 files changed, 6 insertions, 4 deletions

diff --git a/llvm/lib/Analysis/VectorUtils.cpp b/llvm/lib/Analysis/VectorUtils.cpp
index 8040af12d7c..986756eb262 100644
--- a/llvm/lib/Analysis/VectorUtils.cpp
+++ b/llvm/lib/Analysis/VectorUtils.cpp
@@ -37,8 +37,9 @@ static cl::opt<unsigned> MaxInterleaveGroupFactor(
     cl::init(8));
 
 /// Return true if all of the intrinsic's arguments and return type are scalars
-/// for the scalar form of the intrinsic and vectors for the vector form of the
-/// intrinsic.
+/// for the scalar form of the intrinsic, and vectors for the vector form of the
+/// intrinsic (except operands that are marked as always being scalar by
+/// hasVectorInstrinsicScalarOpd).
 bool llvm::isTriviallyVectorizable(Intrinsic::ID ID) {
   switch (ID) {
   case Intrinsic::bswap: // Begin integer bit-manipulation.
@@ -53,6 +54,7 @@ bool llvm::isTriviallyVectorizable(Intrinsic::ID ID) {
   case Intrinsic::uadd_sat:
   case Intrinsic::usub_sat:
   case Intrinsic::smul_fix:
+  case Intrinsic::smul_fix_sat:
   case Intrinsic::umul_fix:
   case Intrinsic::sqrt: // Begin floating-point.
   case Intrinsic::sin:
@@ -85,8 +87,7 @@ bool llvm::isTriviallyVectorizable(Intrinsic::ID ID) {
   }
 }
 
-/// Identifies if the intrinsic has a scalar operand. It check for
-/// ctlz,cttz and powi special intrinsics whose argument is scalar.
+/// Identifies if the vector form of the intrinsic has a scalar operand.
 bool llvm::hasVectorInstrinsicScalarOpd(Intrinsic::ID ID,
                                         unsigned ScalarOpdIdx) {
   switch (ID) {
@@ -95,6 +96,7 @@ bool llvm::hasVectorInstrinsicScalarOpd(Intrinsic::ID ID,
   case Intrinsic::powi:
     return (ScalarOpdIdx == 1);
   case Intrinsic::smul_fix:
+  case Intrinsic::smul_fix_sat:
   case Intrinsic::umul_fix:
     return (ScalarOpdIdx == 2);
   default: