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	Summary: The current code in LoopUnswtich::processCurrentLoop() mixes trivial loop unswitch and non-trivial loop unswitch together. It goes over all basic blocks in the loop and checks if a condition is trivial or non-trivial unswitch condition. However, trivial unswitch condition can only occur in the loop header basic block (where it controls whether or not the loop does something at all). This refactoring separate trivial loop unswitch and non-trivial loop unswitch. Before going over all basic blocks in the loop, it checks if the loop header contains a trivial unswitch condition. If so, unswitch it. Otherwise, go over all blocks like before but don't check trivial condition any more since they are not possible to be in the other blocks. This code has no functionality change. Reviewers: meheff, reames, broune Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D11276 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242873 91177308-0d34-0410-b5e6-96231b3b80d8
		
			
				
	
	
		
			28 lines
		
	
	
		
			811 B
		
	
	
	
		
			LLVM
		
	
	
	
	
	
			
		
		
	
	
			28 lines
		
	
	
		
			811 B
		
	
	
	
		
			LLVM
		
	
	
	
	
	
; RUN: opt < %s -loop-unswitch -loop-unswitch-threshold=0 -S 2>&1 | FileCheck %s
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; This is to test trivial loop unswitch only happens when trivial condition
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; itself is an LIV loop condition (not partial LIV which could occur in and/or).
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define i32 @test(i1 %cond1, i32 %var1) {
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entry:
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  br label %loop_begin
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loop_begin:
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  %var3 = phi i32 [%var1, %entry], [%var2, %do_something]
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  %cond2 = icmp eq i32 %var3, 10
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  %cond.and = and i1 %cond1, %cond2
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; %cond.and only has %cond1 as LIV so no unswitch should happen.
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; CHECK: br i1 %cond.and, label %do_something, label %loop_exit
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  br i1 %cond.and, label %do_something, label %loop_exit 
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do_something:
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  %var2 = add i32 %var3, 1
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  call void @some_func() noreturn nounwind
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  br label %loop_begin
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loop_exit:
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  ret i32 0
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}
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declare void @some_func() noreturn  |