Add an SSE2 algorithm for uint64->f64 conversion.

The same one Apple gcc uses, faster.  Also gets the
extreme case in gcc.c-torture/execute/ieee/rbug.c
correct which we weren't before; this is not
sufficient to get the test to pass though, there
is another bug.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57926 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 53d12b224d..96b427bd80 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -5473,6 +5473,22 @@ ExpandIntToFP(bool isSigned, MVT DestTy, SDValue Source) {
       Hi = Source;
     }
 
+    // Check to see if the target has a custom way to lower this.  If so, use it.
+    // (Note we've already expanded the operand in this case.)
+    switch (TLI.getOperationAction(ISD::UINT_TO_FP, SourceVT)) {
+    default: assert(0 && "This action not implemented for this operation!");
+    case TargetLowering::Legal:
+    case TargetLowering::Expand:
+      break;   // This case is handled below.
+    case TargetLowering::Custom: {
+      SDValue NV = TLI.LowerOperation(DAG.getNode(ISD::UINT_TO_FP, DestTy,
+                                                    Source), DAG);
+      if (NV.getNode())
+        return LegalizeOp(NV);
+      break;   // The target decided this was legal after all
+    }
+    }
+
     // If this is unsigned, and not supported, first perform the conversion to
     // signed, then adjust the result if the sign bit is set.
     SDValue SignedConv = ExpandIntToFP(true, DestTy, Source);