Make the fast-isel code for literal 0.0 a bit shorter/faster, since 0.0 is common. rdar://problem/9303592 .

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130338 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 2 deletions

diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp
index 72c67d596e..211c76b2f3 100644
--- a/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -164,8 +164,12 @@ unsigned FastISel::materializeRegForValue(const Value *V, MVT VT) {
     Reg =
       getRegForValue(Constant::getNullValue(TD.getIntPtrType(V->getContext())));
   } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
-    // Try to emit the constant directly.
-    Reg = FastEmit_f(VT, VT, ISD::ConstantFP, CF);
+    if (CF->isZero()) {
+      Reg = TargetMaterializeFloatZero(CF);
+    } else {
+      // Try to emit the constant directly.
+      Reg = FastEmit_f(VT, VT, ISD::ConstantFP, CF);
+    }
 
     if (!Reg) {
       // Try to emit the constant by using an integer constant with a cast.