88 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			88 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: llc -mtriple=x86_64 -o - %s | FileCheck %s
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define i1 @try_cmpxchg(i32* %addr, i32 %desired, i32 %new) {
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; CHECK-LABEL: try_cmpxchg:
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; CHECK: cmpxchgl
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; CHECK-NOT: cmp
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; CHECK: sete %al
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; CHECK: retq
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  %pair = cmpxchg i32* %addr, i32 %desired, i32 %new seq_cst seq_cst
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  %success = extractvalue { i32, i1 } %pair, 1
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  ret i1 %success
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}
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define void @cmpxchg_flow(i64* %addr, i64 %desired, i64 %new) {
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; CHECK-LABEL: cmpxchg_flow:
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; CHECK: cmpxchgq
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; CHECK-NOT: cmp
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; CHECK-NOT: set
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; CHECK: {{jne|jeq}}
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  %pair = cmpxchg i64* %addr, i64 %desired, i64 %new seq_cst seq_cst
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  %success = extractvalue { i64, i1 } %pair, 1
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  br i1 %success, label %true, label %false
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true:
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  call void @foo()
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  ret void
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false:
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  call void @bar()
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  ret void
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}
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define i64 @cmpxchg_sext(i32* %addr, i32 %desired, i32 %new) {
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; CHECK-LABEL: cmpxchg_sext:
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; CHECK-DAG: cmpxchgl
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; CHECK-NOT: cmpl
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; CHECK: sete %cl
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; CHECK: retq
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  %pair = cmpxchg i32* %addr, i32 %desired, i32 %new seq_cst seq_cst
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  %success = extractvalue { i32, i1 } %pair, 1
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  %mask = sext i1 %success to i64
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  ret i64 %mask
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}
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define i32 @cmpxchg_zext(i32* %addr, i32 %desired, i32 %new) {
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; CHECK-LABEL: cmpxchg_zext:
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; CHECK: xorl %e[[R:[a-z]]]x
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; CHECK: cmpxchgl
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; CHECK-NOT: cmp
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; CHECK: sete %[[R]]l
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  %pair = cmpxchg i32* %addr, i32 %desired, i32 %new seq_cst seq_cst
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  %success = extractvalue { i32, i1 } %pair, 1
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  %mask = zext i1 %success to i32
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  ret i32 %mask
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}
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define i32 @cmpxchg_use_eflags_and_val(i32* %addr, i32 %offset) {
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; CHECK-LABEL: cmpxchg_use_eflags_and_val:
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; CHECK: movl (%rdi), %e[[OLDVAL:[a-z0-9]+]]
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; CHECK: [[LOOPBB:.?LBB[0-9]+_[0-9]+]]:
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; CHECK: leal (%r[[OLDVAL]],%rsi), [[NEW:%[a-z0-9]+]]
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; CHECK: cmpxchgl [[NEW]], (%rdi)
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; CHECK-NOT: cmpl
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; CHECK: jne [[LOOPBB]]
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  ; Result already in %eax
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; CHECK: retq
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entry:
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  %init = load atomic i32, i32* %addr seq_cst, align 4
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  br label %loop
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loop:
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  %old = phi i32 [%init, %entry], [%oldval, %loop]
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  %new = add i32 %old, %offset
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  %pair = cmpxchg i32* %addr, i32 %old, i32 %new seq_cst seq_cst
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  %oldval = extractvalue { i32, i1 } %pair, 0
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  %success = extractvalue { i32, i1 } %pair, 1
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  br i1 %success, label %done, label %loop
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done:
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  ret i32 %oldval
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}
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declare void @foo()
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declare void @bar()
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