98 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			98 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: opt < %s -correlated-propagation -S | FileCheck %s
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; CHECK-LABEL: @test0(
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define void @test0(i32 %n) {
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entry:
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  br label %for.cond
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for.cond:                                         ; preds = %for.body, %entry
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  %j.0 = phi i32 [ %n, %entry ], [ %div, %for.body ]
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  %cmp = icmp sgt i32 %j.0, 1
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  br i1 %cmp, label %for.body, label %for.end
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for.body:                                         ; preds = %for.cond
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; CHECK: %div1 = udiv i32 %j.0, 2
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  %div = sdiv i32 %j.0, 2
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  br label %for.cond
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for.end:                                          ; preds = %for.cond
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  ret void
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}
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; CHECK-LABEL: @test1(
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define void @test1(i32 %n) {
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entry:
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  br label %for.cond
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for.cond:                                         ; preds = %for.body, %entry
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  %j.0 = phi i32 [ %n, %entry ], [ %div, %for.body ]
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  %cmp = icmp sgt i32 %j.0, -2
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  br i1 %cmp, label %for.body, label %for.end
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for.body:                                         ; preds = %for.cond
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; CHECK: %div = sdiv i32 %j.0, 2
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  %div = sdiv i32 %j.0, 2
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  br label %for.cond
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for.end:                                          ; preds = %for.cond
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  ret void
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}
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; CHECK-LABEL: @test2(
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define void @test2(i32 %n) {
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entry:
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  %cmp = icmp sgt i32 %n, 1
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  br i1 %cmp, label %bb, label %exit
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bb:
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; CHECK: %div1 = udiv i32 %n, 2 
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  %div = sdiv i32 %n, 2
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  br label %exit
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exit:
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  ret void
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}
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; looping case where loop has exactly one block
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; at the point of sdiv, we know that %a is always greater than 0,
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; because of the guard before it, so we can transform it to udiv.
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declare void @llvm.experimental.guard(i1,...)
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; CHECK-LABEL: @test4
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define void @test4(i32 %n) {
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entry:
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  %cmp = icmp sgt i32 %n, 0
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  br i1 %cmp, label %loop, label %exit
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loop:
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; CHECK: udiv i32 %a, 6
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  %a = phi i32 [ %n, %entry ], [ %div, %loop ]
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  %cond = icmp sgt i32 %a, 4
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  call void(i1,...) @llvm.experimental.guard(i1 %cond) [ "deopt"() ]
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  %div = sdiv i32 %a, 6
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  br i1 %cond, label %loop, label %exit
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exit:
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  ret void
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}
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; same test as above with assume instead of guard.
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declare void @llvm.assume(i1)
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; CHECK-LABEL: @test5
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define void @test5(i32 %n) {
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entry:
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  %cmp = icmp sgt i32 %n, 0
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  br i1 %cmp, label %loop, label %exit
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loop:
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; CHECK: udiv i32 %a, 6
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  %a = phi i32 [ %n, %entry ], [ %div, %loop ]
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  %cond = icmp sgt i32 %a, 4
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  call void @llvm.assume(i1 %cond)
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  %div = sdiv i32 %a, 6
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  %loopcond = icmp sgt i32 %div, 8
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  br i1 %loopcond, label %loop, label %exit
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exit:
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  ret void
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}
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