enable SDISel sincos optimization for GNU environments

- add sincos to runtime library if target triple environment is GNU
- added canCombineSinCosLibcall() which checks that sincos is in the RTL and
  if the environment is GNU then unsafe fpmath is enabled (required to
  preserve errno)
- extended sincos-opt lit test

Reviewed by: Hal Finkel

llvm-svn: 175283

1 files changed, 16 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 6a3e03b3936..4a0176bc031 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -15,6 +15,7 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Triple.h"
 #include "llvm/CodeGen/Analysis.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineJumpTableInfo.h"
@@ -2111,6 +2112,20 @@ static bool isSinCosLibcallAvailable(SDNode *Node, const TargetLowering &TLI) {
   return TLI.getLibcallName(LC) != 0;
 }
 
+/// canCombineSinCosLibcall - Return true if sincos libcall is available and
+/// can be used to combine sin and cos.
+static bool canCombineSinCosLibcall(SDNode *Node, const TargetLowering &TLI,
+                                    const TargetMachine &TM) {
+  if (!isSinCosLibcallAvailable(Node, TLI))
+    return false;
+  // GNU sin/cos functions set errno while sincos does not. Therefore
+  // combining sin and cos is only safe if unsafe-fpmath is enabled.
+  bool isGNU = Triple(TM.getTargetTriple()).getEnvironment() == Triple::GNU;
+  if (isGNU && !TM.Options.UnsafeFPMath)
+    return false;
+  return true;
+}
+
 /// useSinCos - Only issue sincos libcall if both sin and cos are
 /// needed.
 static bool useSinCos(SDNode *Node) {
@@ -3149,7 +3164,7 @@ void SelectionDAGLegalize::ExpandNode(SDNode *Node) {
     // Turn fsin / fcos into ISD::FSINCOS node if there are a pair of fsin /
     // fcos which share the same operand and both are used.
     if ((TLI.isOperationLegalOrCustom(ISD::FSINCOS, VT) ||
-         isSinCosLibcallAvailable(Node, TLI))
+         canCombineSinCosLibcall(Node, TLI, TM))
         && useSinCos(Node)) {
       SDVTList VTs = DAG.getVTList(VT, VT);
       Tmp1 = DAG.getNode(ISD::FSINCOS, dl, VTs, Node->getOperand(0));