91 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			91 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: opt -simplifycfg -S < %s | FileCheck %s
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define void @ifconvertstore(i32* %A, i32 %B, i32 %C, i32 %D) {
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; CHECK-LABEL: @ifconvertstore(
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; CHECK:         store i32 %B, i32* %A
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; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 %D, 42
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; CHECK-NEXT:    [[C_B:%.*]] = select i1 [[CMP]], i32 %C, i32 %B, !prof !0
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; CHECK-NEXT:    store i32 [[C_B]], i32* %A
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; CHECK-NEXT:    ret void
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;
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entry:
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; First store to the location.
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  store i32 %B, i32* %A
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  %cmp = icmp sgt i32 %D, 42
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  br i1 %cmp, label %if.then, label %ret.end, !prof !0
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; Make sure we speculate stores like the following one. It is cheap compared to
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; a mispredicated branch.
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if.then:
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  store i32 %C, i32* %A
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  br label %ret.end
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ret.end:
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  ret void
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}
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; Store to a different location.
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define void @noifconvertstore1(i32* %A1, i32* %A2, i32 %B, i32 %C, i32 %D) {
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; CHECK-LABEL: @noifconvertstore1(
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; CHECK-NOT: select
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;
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entry:
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  store i32 %B, i32* %A1
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  %cmp = icmp sgt i32 %D, 42
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  br i1 %cmp, label %if.then, label %ret.end
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if.then:
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  store i32 %C, i32* %A2
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  br label %ret.end
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ret.end:
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  ret void
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}
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; This function could store to our address, so we can't repeat the first store a second time.
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declare void @unknown_fun()
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define void @noifconvertstore2(i32* %A, i32 %B, i32 %C, i32 %D) {
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; CHECK-LABEL: @noifconvertstore2(
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; CHECK-NOT: select
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;
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entry:
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; First store to the location.
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  store i32 %B, i32* %A
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  call void @unknown_fun()
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  %cmp6 = icmp sgt i32 %D, 42
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  br i1 %cmp6, label %if.then, label %ret.end
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if.then:
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  store i32 %C, i32* %A
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  br label %ret.end
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ret.end:
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  ret void
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}
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; Make sure we don't speculate volatile stores.
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define void @noifconvertstore_volatile(i32* %A, i32 %B, i32 %C, i32 %D) {
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; CHECK-LABEL: @noifconvertstore_volatile(
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; CHECK-NOT: select
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;
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entry:
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; First store to the location.
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  store i32 %B, i32* %A
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  %cmp6 = icmp sgt i32 %D, 42
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  br i1 %cmp6, label %if.then, label %ret.end
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if.then:
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  store volatile i32 %C, i32* %A
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  br label %ret.end
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ret.end:
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  ret void
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}
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; CHECK: !0 = !{!"branch_weights", i32 3, i32 5}
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!0 = !{!"branch_weights", i32 3, i32 5}
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