[llvm-commits] [llvm] r102683 - in /llvm/trunk: lib/Target/X86/X86ISelLowering.cpp test/CodeGen/X86/sibcall.ll

[Evan Cheng]

Author: evancheng
Date: Thu Apr 29 20:12:32 2010
New Revision: 102683

URL: http://llvm.org/viewvc/llvm-project?rev=102683&view=rev
Log:
Another sibcall bug. If caller and callee calling conventions differ, then it's only safe to do a tail call if the results are returned in the same way.

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
    llvm/trunk/test/CodeGen/X86/sibcall.ll

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=102683&r1=102682&r2=102683&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Thu Apr 29 20:12:32 2010
@@ -2326,9 +2326,11 @@
   // If -tailcallopt is specified, make fastcc functions tail-callable.
   const MachineFunction &MF = DAG.getMachineFunction();
   const Function *CallerF = DAG.getMachineFunction().getFunction();
+  CallingConv::ID CallerCC = CallerF->getCallingConv();
+  bool CCMatch = CallerCC == CalleeCC;
+
   if (GuaranteedTailCallOpt) {
-    if (IsTailCallConvention(CalleeCC) &&
-        CallerF->getCallingConv() == CalleeCC)
+    if (IsTailCallConvention(CalleeCC) && CCMatch)
       return true;
     return false;
   }
@@ -2366,13 +2368,43 @@
     CCState CCInfo(CalleeCC, false, getTargetMachine(),
                    RVLocs, *DAG.getContext());
     CCInfo.AnalyzeCallResult(Ins, RetCC_X86);
-    for (unsigned i = 0; i != RVLocs.size(); ++i) {
+    for (unsigned i = 0, e = RVLocs.size(); i != e; ++i) {
       CCValAssign &VA = RVLocs[i];
       if (VA.getLocReg() == X86::ST0 || VA.getLocReg() == X86::ST1)
         return false;
     }
   }
 
+  // If the calling conventions do not match, then we'd better make sure the
+  // results are returned in the same way as what the caller expects.
+  if (!CCMatch) {
+    SmallVector<CCValAssign, 16> RVLocs1;
+    CCState CCInfo1(CalleeCC, false, getTargetMachine(),
+                    RVLocs1, *DAG.getContext());
+    CCInfo1.AnalyzeCallResult(Ins, RetCC_X86);
+
+    SmallVector<CCValAssign, 16> RVLocs2;
+    CCState CCInfo2(CallerCC, false, getTargetMachine(),
+                    RVLocs2, *DAG.getContext());
+    CCInfo2.AnalyzeCallResult(Ins, RetCC_X86);
+
+    if (RVLocs1.size() != RVLocs2.size())
+      return false;
+    for (unsigned i = 0, e = RVLocs1.size(); i != e; ++i) {
+      if (RVLocs1[i].isRegLoc() != RVLocs2[i].isRegLoc())
+        return false;
+      if (RVLocs1[i].getLocInfo() != RVLocs2[i].getLocInfo())
+        return false;
+      if (RVLocs1[i].isRegLoc()) {
+        if (RVLocs1[i].getLocReg() != RVLocs2[i].getLocReg())
+          return false;
+      } else {
+        if (RVLocs1[i].getLocMemOffset() != RVLocs2[i].getLocMemOffset())
+          return false;
+      }
+    }
+  }
+
   // If the callee takes no arguments then go on to check the results of the
   // call.
   if (!Outs.empty()) {

Modified: llvm/trunk/test/CodeGen/X86/sibcall.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/sibcall.ll?rev=102683&r1=102682&r2=102683&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/sibcall.ll (original)
+++ llvm/trunk/test/CodeGen/X86/sibcall.ll Thu Apr 29 20:12:32 2010
@@ -313,3 +313,21 @@
 }
 
 declare void @foo()
+
+; If caller / callee calling convention mismatch then check if the return
+; values are returned in the same registers.
+; rdar://7874780
+
+define double @t20(double %x) nounwind {
+entry:
+; 32: t20:
+; 32: call {{_?}}foo20
+; 32: fldl (%esp)
+
+; 64: t20:
+; 64: jmp {{_?}}foo20
+  %0 = tail call fastcc double @foo20(double %x) nounwind
+  ret double %0
+}
+
+declare fastcc double @foo20(double) nounwind