38 lines
		
	
	
		
			921 B
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			38 lines
		
	
	
		
			921 B
		
	
	
	
		
			LLVM
		
	
	
	
| ; RUN: opt < %s -reassociate -disable-output
 | |
| 
 | |
| ; It has been detected that dead loops like the one in this test case can be
 | |
| ; created by -jump-threading (it was detected by a csmith generated program).
 | |
| ;
 | |
| ; According to -verify this is valid input (even if it could be discussed if
 | |
| ; the dead loop really satisfies SSA form).
 | |
| ;
 | |
| ; The problem found was that the -reassociate pass ends up in an infinite loop
 | |
| ; when analysing the 'deadloop1' basic block. See "Bugzilla - Bug 30818".
 | |
| define void @deadloop1() {
 | |
|   br label %endlabel
 | |
| 
 | |
| deadloop1:
 | |
|   %1 = xor i32 %2, 7
 | |
|   %2 = xor i32 %1, 8
 | |
|   br label %deadloop1
 | |
| 
 | |
| endlabel:
 | |
|   ret void
 | |
| }
 | |
| 
 | |
| 
 | |
| ; Another example showing that dead code could result in infinite loops in
 | |
| ; reassociate pass. See "Bugzilla - Bug 30818".
 | |
| define void @deadloop2() {
 | |
|   br label %endlabel
 | |
| 
 | |
| deadloop2:
 | |
|   %1 = and i32 %2, 7
 | |
|   %2 = and i32 %3, 8
 | |
|   %3 = and i32 %1, 6
 | |
|   br label %deadloop2
 | |
| 
 | |
| endlabel:
 | |
|   ret void
 | |
| }
 |