[FPEnv] Add fptosi and fptoui constrained intrinsics.

This implements constrained floating point intrinsics for FP to signed and
unsigned integers.

Quoting from D32319:
The purpose of the constrained intrinsics is to force the optimizer to
respect the restrictions that will be necessary to support things like the
STDC FENV_ACCESS ON pragma without interfering with optimizations when
these restrictions are not needed.

Reviewed by:	Andrew Kaylor, Craig Topper, Hal Finkel, Cameron McInally, Roman Lebedev, Kit Barton
Approved by:	Craig Topper
Differential Revision:	http://reviews.llvm.org/D63782

llvm-svn: 370228

1 files changed, 10 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
index a892fccc8a1..4b8656805f3 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
@@ -333,6 +333,8 @@ SDValue VectorLegalizer::LegalizeOp(SDValue Op) {
   case ISD::STRICT_FFLOOR:
   case ISD::STRICT_FROUND:
   case ISD::STRICT_FTRUNC:
+  case ISD::STRICT_FP_TO_SINT:
+  case ISD::STRICT_FP_TO_UINT:
   case ISD::STRICT_FP_ROUND:
   case ISD::STRICT_FP_EXTEND:
     Action = TLI.getOperationAction(Node->getOpcode(), Node->getValueType(0));
@@ -862,6 +864,8 @@ SDValue VectorLegalizer::Expand(SDValue Op) {
   case ISD::STRICT_FFLOOR:
   case ISD::STRICT_FROUND:
   case ISD::STRICT_FTRUNC:
+  case ISD::STRICT_FP_TO_SINT:
+  case ISD::STRICT_FP_TO_UINT:
     return ExpandStrictFPOp(Op);
   case ISD::VECREDUCE_ADD:
   case ISD::VECREDUCE_MUL:
@@ -1186,9 +1190,13 @@ SDValue VectorLegalizer::ExpandABS(SDValue Op) {
 
 SDValue VectorLegalizer::ExpandFP_TO_UINT(SDValue Op) {
   // Attempt to expand using TargetLowering.
-  SDValue Result;
-  if (TLI.expandFP_TO_UINT(Op.getNode(), Result, DAG))
+  SDValue Result, Chain;
+  if (TLI.expandFP_TO_UINT(Op.getNode(), Result, Chain, DAG)) {
+    if (Op.getNode()->isStrictFPOpcode())
+      // Relink the chain
+      DAG.ReplaceAllUsesOfValueWith(Op.getValue(1), Chain);
     return Result;
+  }
 
   // Otherwise go ahead and unroll.
   return DAG.UnrollVectorOp(Op.getNode());