Optimize local func calls to not emit nop for TOC restoration.

Patch by Adhemerval Zanella.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164138 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 59 insertions, 2 deletions

diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index f1a673c3cc..6b93d945f8 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -2808,6 +2808,14 @@ unsigned PrepareCall(SelectionDAG &DAG, SDValue &Callee, SDValue &InFlag,
   return CallOpc;
 }
 
+static
+bool isLocalCall(const SDValue &Callee)
+{
+  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
+    return !G->getGlobal()->isDeclaration();
+  return false;
+}
+
 SDValue
 PPCTargetLowering::LowerCallResult(SDValue Chain, SDValue InFlag,
                                    CallingConv::ID CallConv, bool isVarArg,
@@ -2916,8 +2924,8 @@ PPCTargetLowering::FinishCall(CallingConv::ID CallConv, DebugLoc dl,
       // from allocating it), resulting in an additional register being
       // allocated and an unnecessary move instruction being generated.
       needsTOCRestore = true;
-    } else if (CallOpc == PPCISD::CALL_SVR4) {
-      // Otherwise insert NOP.
+    } else if ((CallOpc == PPCISD::CALL_SVR4) && !isLocalCall(Callee)) {
+      // Otherwise insert NOP for non-local calls.
       CallOpc = PPCISD::CALL_NOP_SVR4;
     }
   }
diff --git a/test/CodeGen/PowerPC/ppc64-calls.ll b/test/CodeGen/PowerPC/ppc64-calls.ll
new file mode 100644
index 0000000000..1193fd2d8d
--- /dev/null
+++ b/test/CodeGen/PowerPC/ppc64-calls.ll
@@ -0,0 +1,49 @@
+; RUN: llc < %s -march=ppc64 | FileCheck %s
+target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v128:128:128-n32:64"
+target triple = "powerpc64-unknown-linux-gnu"
+
+define void @foo() nounwind readnone noinline {
+  ret void
+}
+
+; Calls to local function does not require the TOC restore 'nop'
+define void @test_direct() nounwind readnone {
+; CHECK: test_direct:
+  tail call void @foo() nounwind
+; CHECK: bl foo
+; CHECK-NOT: nop
+  ret void
+}
+
+; Indirect calls requires a full stub creation
+define void @test_indirect(void ()* nocapture %fp) nounwind {
+; CHECK: test_indirect:
+  tail call void %fp() nounwind
+; CHECK: ld [[FP:[0-9]+]], 0(3)
+; CHECK: ld 11, 16(3)
+; CHECK: ld 2, 8(3)
+; CHECK-NEXT: mtctr [[FP]]
+; CHECK-NEXT: bctrl
+; CHECK-NEXT: ld 2, 40(1)
+  ret void
+}
+
+; Absolute vales should be have the TOC restore 'nop'
+define void @test_abs() nounwind {
+; CHECK: test_abs:
+  tail call void inttoptr (i64 1024 to void ()*)() nounwind
+; CHECK: bla 1024
+; CHECK-NEXT: nop
+  ret void
+}
+
+declare double @sin(double) nounwind
+
+; External functions call should also have a 'nop'
+define double @test_external(double %x) nounwind {
+; CHECK: test_external:
+  %call = tail call double @sin(double %x) nounwind
+; CHECK: bl sin
+; CHECK-NEXT: nop
+  ret double %call
+}