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comparison test/CodeGen/X86/vec_fneg.ll @ 77:54457678186b LLVM3.6

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LLVM 3.6
author Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
date Mon, 08 Sep 2014 22:06:00 +0900
parents 95c75e76d11b
children 60c9769439b8
comparison
equal deleted inserted replaced
34:e874dbf0ad9d 77:54457678186b
1 ; RUN: llc < %s -march=x86 -mattr=+sse2 1 ; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mcpu=corei7 | FileCheck %s
2 2
3 ; FNEG is defined as subtraction from -0.0.
4
5 ; This test verifies that we use an xor with a constant to flip the sign bits; no subtraction needed.
3 define <4 x float> @t1(<4 x float> %Q) { 6 define <4 x float> @t1(<4 x float> %Q) {
4 %tmp15 = fsub <4 x float> < float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00 >, %Q 7 ; CHECK-LABEL: t1:
5 ret <4 x float> %tmp15 8 ; CHECK: xorps {{.*}}LCPI0_0{{.*}}, %xmm0
9 ; CHECK-NEXT: retq
10 %tmp = fsub <4 x float> < float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00 >, %Q
11 ret <4 x float> %tmp
6 } 12 }
7 13
14 ; This test verifies that we generate an FP subtraction because "0.0 - x" is not an fneg.
8 define <4 x float> @t2(<4 x float> %Q) { 15 define <4 x float> @t2(<4 x float> %Q) {
9 %tmp15 = fsub <4 x float> zeroinitializer, %Q 16 ; CHECK-LABEL: t2:
10 ret <4 x float> %tmp15 17 ; CHECK: xorps %[[X:xmm[0-9]+]], %[[X]]
18 ; CHECK-NEXT: subps %xmm0, %[[X]]
19 ; CHECK-NEXT: movaps %[[X]], %xmm0
20 ; CHECK-NEXT: retq
21 %tmp = fsub <4 x float> zeroinitializer, %Q
22 ret <4 x float> %tmp
11 } 23 }
24
25 ; If we're bitcasting an integer to an FP vector, we should avoid the FPU/vector unit entirely.
26 ; Make sure that we're flipping the sign bit and only the sign bit of each float.
27 ; So instead of something like this:
28 ; movd %rdi, %xmm0
29 ; xorps .LCPI2_0(%rip), %xmm0
30 ;
31 ; We should generate:
32 ; movabsq (put sign bit mask in integer register))
33 ; xorq (flip sign bits)
34 ; movd (move to xmm return register)
35
36 define <2 x float> @fneg_bitcast(i64 %i) {
37 ; CHECK-LABEL: fneg_bitcast:
38 ; CHECK: movabsq $-9223372034707292160, %rax # imm = 0x8000000080000000
39 ; CHECK-NEXT: xorq %rdi, %rax
40 ; CHECK-NEXT: movd %rax, %xmm0
41 ; CHECK-NEXT: retq
42 %bitcast = bitcast i64 %i to <2 x float>
43 %fneg = fsub <2 x float> <float -0.0, float -0.0>, %bitcast
44 ret <2 x float> %fneg
45 }