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			46 lines
		
	
	
		
			1.6 KiB
		
	
	
	
		
			LLVM
		
	
	
	
	
	
			
		
		
	
	
			46 lines
		
	
	
		
			1.6 KiB
		
	
	
	
		
			LLVM
		
	
	
	
	
	
| ; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=sse | FileCheck %s
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| 
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| ; FNEG is defined as subtraction from -0.0.
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| 
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| ; This test verifies that we use an xor with a constant to flip the sign bits; no subtraction needed.
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| define <4 x float> @t1(<4 x float> %Q) {
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| ; CHECK-LABEL: t1:
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| ; CHECK: xorps	{{.*}}LCPI0_0{{.*}}, %xmm0
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| ; CHECK-NEXT: retq
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|         %tmp = fsub <4 x float> < float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00 >, %Q
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| 	ret <4 x float> %tmp
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| }
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| 
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| ; This test verifies that we generate an FP subtraction because "0.0 - x" is not an fneg.
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| define <4 x float> @t2(<4 x float> %Q) {
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| ; CHECK-LABEL: t2:
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| ; CHECK: xorps	%[[X:xmm[0-9]+]], %[[X]]
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| ; CHECK-NEXT: subps	%xmm0, %[[X]]
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| ; CHECK-NEXT: movaps	%[[X]], %xmm0
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| ; CHECK-NEXT: retq
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|         %tmp = fsub <4 x float> zeroinitializer, %Q
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| 	ret <4 x float> %tmp
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| }
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| 
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| ; If we're bitcasting an integer to an FP vector, we should avoid the FPU/vector unit entirely.
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| ; Make sure that we're flipping the sign bit and only the sign bit of each float.
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| ; So instead of something like this:
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| ;    movd	%rdi, %xmm0
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| ;    xorps	.LCPI2_0(%rip), %xmm0
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| ;
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| ; We should generate:
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| ;    movabsq     (put sign bit mask in integer register))
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| ;    xorq        (flip sign bits)
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| ;    movd        (move to xmm return register) 
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| 
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| define <2 x float> @fneg_bitcast(i64 %i) {
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| ; CHECK-LABEL: fneg_bitcast:
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| ; CHECK:	movabsq	$-9223372034707292160, %rax # imm = 0x8000000080000000
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| ; CHECK-NEXT:	xorq	%rdi, %rax
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| ; CHECK-NEXT:	movd	%rax, %xmm0
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| ; CHECK-NEXT:	retq
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|   %bitcast = bitcast i64 %i to <2 x float>
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|   %fneg = fsub <2 x float> <float -0.0, float -0.0>, %bitcast
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|   ret <2 x float> %fneg
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| }
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