[llvm-commits] [llvm] r94946 - in /llvm/trunk: lib/Target/X86/X86ISelLowering.cpp test/CodeGen/X86/tailcall2.ll
Evan Cheng
evan.cheng at apple.com
Sat Jan 30 22:44:50 PST 2010
Author: evancheng
Date: Sun Jan 31 00:44:49 2010
New Revision: 94946
URL: http://llvm.org/viewvc/llvm-project?rev=94946&view=rev
Log:
Avoid recursive sibcall's.
Modified:
llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
llvm/trunk/test/CodeGen/X86/tailcall2.ll
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=94946&r1=94945&r2=94946&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Sun Jan 31 00:44:49 2010
@@ -2252,10 +2252,26 @@
// If -tailcallopt is specified, make fastcc functions tail-callable.
const Function *CallerF = DAG.getMachineFunction().getFunction();
- if (PerformTailCallOpt &&
- CalleeCC == CallingConv::Fast &&
- CallerF->getCallingConv() == CalleeCC)
- return true;
+ if (PerformTailCallOpt) {
+ if (CalleeCC == CallingConv::Fast &&
+ CallerF->getCallingConv() == CalleeCC)
+ return true;
+ return false;
+ }
+
+ // Do not tail call optimize vararg calls for now.
+ if (isVarArg)
+ return false;
+
+ // Don't tail call optimize recursive call.
+ GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee);
+ const Function *CalleeF = G ? cast<Function>(G->getGlobal()) : 0;
+ if (CallerF == CalleeF)
+ return false;
+ // If it's an indirect call, conversatively return false if the caller's
+ // address is taken.
+ if (!isa<ExternalSymbolSDNode>(Callee) && CallerF->hasAddressTaken())
+ return false;
// Look for obvious safe cases to perform tail call optimization.
// If the callee takes no arguments then go on to check the results of the
@@ -2279,9 +2295,7 @@
return true;
// If the return types match, then it's safe.
- GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee);
if (!G) return false; // FIXME: common external symbols?
- Function *CalleeF = cast<Function>(G->getGlobal());
const Type *CalleeRetTy = CalleeF->getReturnType();
return CallerRetTy == CalleeRetTy;
}
Modified: llvm/trunk/test/CodeGen/X86/tailcall2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/tailcall2.ll?rev=94946&r1=94945&r2=94946&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/tailcall2.ll (original)
+++ llvm/trunk/test/CodeGen/X86/tailcall2.ll Sun Jan 31 00:44:49 2010
@@ -65,3 +65,27 @@
tail call void %x() nounwind
ret void
}
+
+define i32 @t6(i32 %x) nounwind ssp {
+entry:
+; 32: t6:
+; 32: call {{_?}}t6
+; 32: call {{_?}}bar
+
+; 64: t6:
+; 64: callq {{_?}}t6
+; 64: jmp {{_?}}bar
+ %0 = icmp slt i32 %x, 10
+ br i1 %0, label %bb, label %bb1
+
+bb:
+ %1 = add nsw i32 %x, -1
+ %2 = tail call i32 @t6(i32 %1) nounwind ssp
+ ret i32 %2
+
+bb1:
+ %3 = tail call i32 @bar(i32 %x) nounwind
+ ret i32 %3
+}
+
+declare i32 @bar(i32)
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