[SDAG] Support vector UMULO/SMULO

Second part of https://bugs.llvm.org/show_bug.cgi?id=40442.

This adds an extra UnrollVectorOverflowOp() method to SDAG, because
the general UnrollOverflowOp() method can't deal with multiple results.

Additionally we need to expand UMULO/SMULO during vector op
legalization, as it may result in unrolling, which may need additional
type legalization.

Differential Revision: https://reviews.llvm.org/D57997

llvm-svn: 354513

2 files changed, 9 insertions, 3 deletions

diff --git a/llvm/include/llvm/CodeGen/SelectionDAG.h b/llvm/include/llvm/CodeGen/SelectionDAG.h
index c4755995526..b76f7315013 100644
--- a/llvm/include/llvm/CodeGen/SelectionDAG.h
+++ b/llvm/include/llvm/CodeGen/SelectionDAG.h
@@ -1535,6 +1535,11 @@ public:
   /// vector op and fill the end of the resulting vector with UNDEFS.
   SDValue UnrollVectorOp(SDNode *N, unsigned ResNE = 0);
 
+  /// Like UnrollVectorOp(), but for the [US](ADD|SUB|MUL)O family of opcodes.
+  /// This is a separate function because those opcodes have two results.
+  std::pair<SDValue, SDValue> UnrollVectorOverflowOp(SDNode *N,
+                                                     unsigned ResNE = 0);
+
   /// Return true if loads are next to each other and can be
   /// merged. Check that both are nonvolatile and if LD is loading
   /// 'Bytes' bytes from a location that is 'Dist' units away from the
diff --git a/llvm/include/llvm/CodeGen/TargetLowering.h b/llvm/include/llvm/CodeGen/TargetLowering.h
index 5e633fbb589..ed3b204d9cc 100644
--- a/llvm/include/llvm/CodeGen/TargetLowering.h
+++ b/llvm/include/llvm/CodeGen/TargetLowering.h
@@ -3888,9 +3888,10 @@ public:
   /// integers as its arguments.
   SDValue expandFixedPointMul(SDNode *Node, SelectionDAG &DAG) const;
 
-  /// Method for building the DAG expansion of ISD::[US]MULO, returning the two
-  /// result values as a pair.
-  std::pair<SDValue, SDValue> expandMULO(SDNode *Node, SelectionDAG &DAG) const;
+  /// Method for building the DAG expansion of ISD::[US]MULO. Returns whether
+  /// expansion was successful and populates the Result and Overflow arguments.
+  bool expandMULO(SDNode *Node, SDValue &Result, SDValue &Overflow,
+                  SelectionDAG &DAG) const;
 
   //===--------------------------------------------------------------------===//
   // Instruction Emitting Hooks