Fix a crash in the pre-alloc splitter exposed by recent codegen changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65121 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/PreAllocSplitting.cpp b/lib/CodeGen/PreAllocSplitting.cpp
index ef2cfdb9828d17803556bf8ba65168534d80036c..9e955bd69690d7b169bc56dda7af64b26d833977 100644 (file)
--- a/lib/CodeGen/PreAllocSplitting.cpp
+++ b/lib/CodeGen/PreAllocSplitting.cpp
@@ -224,6 +224,9 @@ PreAllocSplitting::findSpillPoint(MachineBasicBlock *MBB, MachineInstr *MI,
   if (RefsInMBB.empty() && !DefMI) {
     MachineBasicBlock::iterator MII = MBB->begin();
     MachineBasicBlock::iterator EndPt = MI;
+    
+    if (MII == EndPt) return Pt;
+    
     do {
       ++MII;
       unsigned Index = LIs->getInstructionIndex(MII);
@@ -303,6 +306,9 @@ PreAllocSplitting::findRestorePoint(MachineBasicBlock *MBB, MachineInstr *MI,
   if (RefsInMBB.empty() && LastIdx >= EndIdx) {
     MachineBasicBlock::iterator MII = MBB->getFirstTerminator();
     MachineBasicBlock::iterator EndPt = MI;
+    
+    if (MII == EndPt) return Pt;
+    
     --MII;
     do {
       unsigned Index = LIs->getInstructionIndex(MII);

diff --git a/test/CodeGen/X86/2009-02-20-PreAllocSplit-Crash.ll b/test/CodeGen/X86/2009-02-20-PreAllocSplit-Crash.ll
new file mode 100644 (file)
index 0000000..54fcd43
--- /dev/null
+++ b/test/CodeGen/X86/2009-02-20-PreAllocSplit-Crash.ll
@@ -0,0 +1,71 @@
+; RUN: llvm-as < %s | llc -march=x86 -mtriple=i386-apple-darwin8 -pre-alloc-split
+
+define i32 @main() nounwind {
+bb4.i.thread:
+       br label %bb5.i4
+
+bb16:          ; preds = %bb111.i
+       %phitmp = add i32 %indvar.reg2mem.4, 1          ; <i32> [#uses=2]
+       switch i32 %indvar.reg2mem.4, label %bb100.i [
+               i32 0, label %bb5.i4
+               i32 1, label %bb5.i4
+               i32 2, label %bb5.i4
+               i32 5, label %bb.i14.i
+               i32 6, label %bb.i14.i
+               i32 7, label %bb.i14.i
+       ]
+
+bb5.i4:                ; preds = %bb16, %bb16, %bb16, %bb4.i.thread
+       br i1 false, label %bb102.i, label %bb103.i
+
+bb.i14.i:              ; preds = %bb16, %bb16, %bb16
+       %0 = malloc [600 x i32]         ; <[600 x i32]*> [#uses=0]
+       %1 = icmp eq i32 %phitmp, 7             ; <i1> [#uses=1]
+       %tl.0.i = select i1 %1, float 1.000000e+02, float 1.000000e+00          ; <float> [#uses=1]
+       %2 = icmp eq i32 %phitmp, 8             ; <i1> [#uses=1]
+       %tu.0.i = select i1 %2, float 1.000000e+02, float 1.000000e+00          ; <float> [#uses=1]
+       br label %bb30.i
+
+bb30.i:                ; preds = %bb36.i, %bb.i14.i
+       %i.1173.i = phi i32 [ 0, %bb.i14.i ], [ %indvar.next240.i, %bb36.i ]            ; <i32> [#uses=3]
+       %3 = icmp eq i32 0, %i.1173.i           ; <i1> [#uses=1]
+       br i1 %3, label %bb33.i, label %bb34.i
+
+bb33.i:                ; preds = %bb30.i
+       store float %tl.0.i, float* null, align 4
+       br label %bb36.i
+
+bb34.i:                ; preds = %bb30.i
+       %4 = icmp eq i32 0, %i.1173.i           ; <i1> [#uses=1]
+       br i1 %4, label %bb35.i, label %bb36.i
+
+bb35.i:                ; preds = %bb34.i
+       store float %tu.0.i, float* null, align 4
+       br label %bb36.i
+
+bb36.i:                ; preds = %bb35.i, %bb34.i, %bb33.i
+       %indvar.next240.i = add i32 %i.1173.i, 1                ; <i32> [#uses=1]
+       br label %bb30.i
+
+bb100.i:               ; preds = %bb16
+       ret i32 0
+
+bb102.i:               ; preds = %bb5.i4
+       br label %bb103.i
+
+bb103.i:               ; preds = %bb102.i, %bb5.i4
+       %indvar.reg2mem.4 = phi i32 [ 0, %bb5.i4 ], [ 0, %bb102.i ]             ; <i32> [#uses=2]
+       %n.0.reg2mem.1.i = phi i32 [ 0, %bb102.i ], [ 0, %bb5.i4 ]              ; <i32> [#uses=1]
+       %5 = icmp eq i32 0, 0           ; <i1> [#uses=1]
+       br i1 %5, label %bb111.i, label %bb108.i
+
+bb108.i:               ; preds = %bb103.i
+       ret i32 0
+
+bb111.i:               ; preds = %bb103.i
+       %6 = icmp sgt i32 %n.0.reg2mem.1.i, 7           ; <i1> [#uses=1]
+       br i1 %6, label %bb16, label %bb112.i
+
+bb112.i:               ; preds = %bb111.i
+       unreachable
+}