52 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			52 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: llc -mtriple=x86_64-apple-macosx -mattr=+cx16 -x86-use-base-pointer=true -stackrealign -stack-alignment=32  %s -o - | FileCheck --check-prefix=CHECK --check-prefix=USE_BASE --check-prefix=USE_BASE_64 %s
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; RUN: llc -mtriple=x86_64-apple-macosx -mattr=+cx16 -x86-use-base-pointer=false -stackrealign -stack-alignment=32  %s -o - | FileCheck --check-prefix=CHECK --check-prefix=DONT_USE_BASE %s
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; RUN: llc -mtriple=x86_64-linux-gnux32 -mattr=+cx16 -x86-use-base-pointer=true -stackrealign -stack-alignment=32  %s -o - | FileCheck --check-prefix=CHECK --check-prefix=USE_BASE --check-prefix=USE_BASE_32 %s
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; RUN: llc -mtriple=x86_64-linux-gnux32 -mattr=+cx16 -x86-use-base-pointer=false -stackrealign -stack-alignment=32  %s -o - | FileCheck --check-prefix=CHECK --check-prefix=DONT_USE_BASE %s
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; This function uses dynamic allocated stack to force the use
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; of a frame pointer.
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; The inline asm clobbers a bunch of registers to make sure
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; the frame pointer will need to be used (for spilling in that case).
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;
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; Then, we check that when we use rbx as the base pointer,
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; we do not use cmpxchg, since using that instruction requires
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; to clobbers rbx to set the arguments of the instruction and when
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; rbx is used as the base pointer, RA cannot fix the code for us.
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;
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; CHECK-LABEL: cmp_and_swap16:
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; Check that we actually use rbx.
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; gnux32 use the 32bit variant of the registers.
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; USE_BASE_64: movq %rsp, %rbx
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; USE_BASE_32: movl %esp, %ebx
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;
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; Make sure the base pointer is saved before the rbx argument for
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; cmpxchg16b is set.
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;
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; Because of how the test is written, we spill SAVE_rbx.
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; However, it would have been perfectly fine to just keep it in register.
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; USE_BASE: movq %rbx, [[SAVE_rbx_SLOT:[0-9]*\(%[er]bx\)]]
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;
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; SAVE_rbx must be in register before we clobber rbx.
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; It is fine to use any register but rbx and the ones defined and use
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; by cmpxchg. Since such regex would be complicated to write, just stick
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; to the numbered registers. The bottom line is: if this test case fails
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; because of that regex, this is likely just the regex being too conservative. 
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; USE_BASE: movq [[SAVE_rbx_SLOT]], [[SAVE_rbx:%r[0-9]+]]
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;
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; USE_BASE: movq {{[^ ]+}}, %rbx
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; USE_BASE-NEXT: cmpxchg16b
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; USE_BASE-NEXT: movq [[SAVE_rbx]], %rbx
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;
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; DONT_USE_BASE-NOT: movq %rsp, %rbx
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; DONT_USE_BASE-NOT: movl %esp, %ebx
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; DONT_USE_BASE: cmpxchg
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define i1 @cmp_and_swap16(i128 %a, i128 %b, i128* %addr, i32 %n) {
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  %dummy = alloca i32, i32 %n
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tail call void asm sideeffect "nop", "~{rax},~{rcx},~{rdx},~{rsi},~{rdi},~{rbp},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15}"()
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  %cmp = cmpxchg i128* %addr, i128 %a, i128 %b seq_cst seq_cst
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  %res = extractvalue { i128, i1 } %cmp, 1
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  %idx = getelementptr i32, i32* %dummy, i32 5
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  store i32 %n, i32* %idx
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  ret i1 %res
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}
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