Tweak unnamed label syntax in textual IR for easier matching in tests.

[eugenis]

Summary

Change the unnamed label comments like

; <label>:8  ; preds = %1

to

; <label>:8:  ; preds = %1

This way lit tests can match [[LABEL]]: in both asserts and no-asserts builds.

[pcc]

LGTM

We should eventually make it so that numeric labels need to appear explicitly in the textual IR (as a non-comment) rather than being implied by a terminator. But this is definitely an improvement on the status quo.

[eugenis]

Thanks, committed as r258993.

lib/IR/AsmWriter.cpp

void AssemblyWriter::printBasicBlock(const BasicBlock *BB) {
   if (BB->hasName()) {              // Print out the label if it exists...
     Out << "\n";
     PrintLLVMName(Out, BB->getName(), LabelPrefix);
     Out << ':';
   } else if (!BB->use_empty()) {      // Don't print block # of no uses...
     Out << "\n; <label>:";
     int Slot = Machine.getLocalSlot(BB);
     if (Slot != -1)
-      Out << Slot;
+      Out << Slot << ":";
     else
       Out << "<badref>";
   }
 
   if (!BB->getParent()) {
     Out.PadToColumn(50);
     Out << "; Error: Block without parent!";
   } else if (BB != &BB->getParent()->getEntryBlock()) {  // Not the entry block?

test/Transforms/SimplifyCFG/merge-cond-stores-2.ll

 ; CHECK: select
 ; CHECK: select
 ; CHECK: select
 ; CHECK: select
 ; CHECK: select
 ; CHECK: select
 ; CHECK-NOT: select
 ; CHECK: br i1 {{.*}}, label %[[L:.*]], label %[[R:.*]]
-; CHECK: [[L]] ; preds = 
+; CHECK: [[L]]: ; preds =
 ; CHECK-NEXT: store
 ; CHECK-NEXT: br label %[[R]]
-; CHECK: [[R]] ; preds = 
+; CHECK: [[R]]: ; preds =
 ; CHECK-NEXT: ret i32 0
 
 define i32 @f(i32* %b) {
 entry:
   %0 = load i32, i32* %b, align 4
   %and = and i32 %0, 1
   %tobool = icmp eq i32 %and, 0
   br i1 %tobool, label %if.end, label %if.then