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