Unallocatable registers do not have live intervals.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56287 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp
index e06eb161c089b6f21d9af8972c723af3c54a5837..0044f06d33d079a6e38af4825bee3e9e74b4e3ff 100644 (file)
--- a/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -568,7 +568,9 @@ SimpleRegisterCoalescing::UpdateRegDefsUses(unsigned SrcReg, unsigned DstReg,
     unsigned CopySrcReg, CopyDstReg;
     if (TID.getNumDefs() == 1 && TID.getNumOperands() > 2 &&
         tii_->isMoveInstr(*UseMI, CopySrcReg, CopyDstReg) &&
-        CopySrcReg != CopyDstReg) {
+        CopySrcReg != CopyDstReg &&
+        (TargetRegisterInfo::isVirtualRegister(CopyDstReg) ||
+         allocatableRegs_[CopyDstReg])) {
       LiveInterval &LI = li_->getInterval(CopyDstReg);
       unsigned DefIdx = li_->getDefIndex(li_->getInstructionIndex(UseMI));
       const LiveRange *DLR = LI.getLiveRangeContaining(DefIdx);

diff --git a/test/CodeGen/ARM/2008-09-17-CoalescerBug.ll b/test/CodeGen/ARM/2008-09-17-CoalescerBug.ll
new file mode 100644 (file)
index 0000000..b3ea6fc
--- /dev/null
+++ b/test/CodeGen/ARM/2008-09-17-CoalescerBug.ll
@@ -0,0 +1,17 @@
+; RUN: llvm-as < %s | llc -mtriple=arm-apple-darwin
+
+define void @gcov_exit() nounwind {
+entry:
+       br i1 false, label %bb24, label %bb33.thread
+
+bb24:          ; preds = %entry
+       br label %bb39
+
+bb33.thread:           ; preds = %entry
+       %0 = alloca i8, i32 0           ; <i8*> [#uses=1]
+       br label %bb39
+
+bb39:          ; preds = %bb33.thread, %bb24
+       %.reg2mem.0 = phi i8* [ %0, %bb33.thread ], [ null, %bb24 ]             ; <i8*> [#uses=0]
+       ret void
+}