Local register allocator shouldn't assume only the entry and landing pad basic blocks have live-ins.

llvm-svn: 63323

llvm/lib/CodeGen/RegAllocLocal.cpp

@@ -710,9 +710,7 @@ void RALocal::AllocateBasicBlock(MachineBasicBlock &MBB) {
   DEBUG(const BasicBlock *LBB = MBB.getBasicBlock();
         if (LBB) DOUT << "\nStarting RegAlloc of BB: " << LBB->getName());
 
-  // If this is the first basic block in the machine function, add live-in
+  // Add live-in registers as active.
-  // registers as active.
-  if (&MBB == &*MF->begin() || MBB.isLandingPad()) {
   for (MachineBasicBlock::livein_iterator I = MBB.livein_begin(),
          E = MBB.livein_end(); I != E; ++I) {
     unsigned Reg = *I;
@@ -728,7 +726,6 @@ void RALocal::AllocateBasicBlock(MachineBasicBlock &MBB) {
       }
     }
   }
-  }
   
   ComputeLocalLiveness(MBB);
   

llvm/test/CodeGen/X86/2009-01-29-LocalRegAllocBug.ll

@@ -0,0 +1,38 @@
+; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin9.6 -regalloc=local -disable-fp-elim
+; rdar://6538384
+
+	%struct.FILE = type { i8*, i32, i32, i16, i16, %struct.__sbuf, i32, i8*, i32 (i8*)*, i32 (i8*, i8*, i32)*, i64 (i8*, i64, i32)*, i32 (i8*, i8*, i32)*, %struct.__sbuf, %struct.__sFILEX*, i32, [3 x i8], [1 x i8], %struct.__sbuf, i32, i64 }
+	%struct.Lit = type { i32 }
+	%struct.StreamBuffer = type { %struct.FILE*, [1048576 x i8], i32, i32 }
+	%struct.__sFILEX = type opaque
+	%struct.__sbuf = type { i8*, i32 }
+
+declare fastcc i32 @_Z8parseIntI12StreamBufferEiRT_(%struct.StreamBuffer*)
+
+declare i8* @llvm.eh.exception() nounwind
+
+define i32 @main(i32 %argc, i8** nocapture %argv) noreturn {
+entry:
+	%0 = invoke fastcc i32 @_Z8parseIntI12StreamBufferEiRT_(%struct.StreamBuffer* null)
+			to label %bb1.i16.i.i unwind label %lpad.i.i		; <i32> [#uses=0]
+
+bb1.i16.i.i:		; preds = %entry
+	br i1 false, label %bb.i.i.i.i, label %_ZN3vecI3LitE4pushERKS0_.exit.i.i.i
+
+bb.i.i.i.i:		; preds = %bb1.i16.i.i
+	br label %_ZN3vecI3LitE4pushERKS0_.exit.i.i.i
+
+_ZN3vecI3LitE4pushERKS0_.exit.i.i.i:		; preds = %bb.i.i.i.i, %bb1.i16.i.i
+	%lits.i.i.0.0 = phi %struct.Lit* [ null, %bb1.i16.i.i ], [ null, %bb.i.i.i.i ]		; <%struct.Lit*> [#uses=1]
+	%1 = invoke fastcc i32 @_Z8parseIntI12StreamBufferEiRT_(%struct.StreamBuffer* null)
+			to label %.noexc21.i.i unwind label %lpad.i.i		; <i32> [#uses=0]
+
+.noexc21.i.i:		; preds = %_ZN3vecI3LitE4pushERKS0_.exit.i.i.i
+	unreachable
+
+lpad.i.i:		; preds = %_ZN3vecI3LitE4pushERKS0_.exit.i.i.i, %entry
+	%lits.i.i.0.3 = phi %struct.Lit* [ %lits.i.i.0.0, %_ZN3vecI3LitE4pushERKS0_.exit.i.i.i ], [ null, %entry ]		; <%struct.Lit*> [#uses=1]
+	%eh_ptr.i.i = call i8* @llvm.eh.exception()		; <i8*> [#uses=0]
+	free %struct.Lit* %lits.i.i.0.3
+	unreachable
+}