[x86] add test for WriteZero sched class instructions; NFC

Nops should have zero latency because there is no result.
Idioms like 'xorps xmm0, xmm0' may have zero latency because 
they are handled without using an execution unit.

llvm-svn: 327435

1 files changed, 92 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/sse-schedule.ll b/llvm/test/CodeGen/X86/sse-schedule.ll
index d53db250baf..8ebea98274d 100644
--- a/llvm/test/CodeGen/X86/sse-schedule.ll
+++ b/llvm/test/CodeGen/X86/sse-schedule.ll
@@ -3763,4 +3763,96 @@ define <4 x float> @test_xorps(<4 x float> %a0, <4 x float> %a1, <4 x float> *%a
   ret <4 x float> %7
 }
 
+; 'WriteZero' class instructions.
+
+define <4 x float> @test_fnop() nounwind {
+; GENERIC-LABEL: test_fnop:
+; GENERIC:       # %bb.0:
+; GENERIC-NEXT:    #APP
+; GENERIC-NEXT:    nop # sched: [1:?]
+; GENERIC-NEXT:    #NO_APP
+; GENERIC-NEXT:    xorps %xmm0, %xmm0 # sched: [1:1.00]
+; GENERIC-NEXT:    retq # sched: [1:1.00]
+;
+; ATOM-LABEL: test_fnop:
+; ATOM:       # %bb.0:
+; ATOM-NEXT:    xorps %xmm0, %xmm0 # sched: [1:0.50]
+; ATOM-NEXT:    #APP
+; ATOM-NEXT:    nop # sched: [1:0.50]
+; ATOM-NEXT:    #NO_APP
+; ATOM-NEXT:    nop # sched: [1:0.50]
+; ATOM-NEXT:    nop # sched: [1:0.50]
+; ATOM-NEXT:    nop # sched: [1:0.50]
+; ATOM-NEXT:    nop # sched: [1:0.50]
+; ATOM-NEXT:    nop # sched: [1:0.50]
+; ATOM-NEXT:    nop # sched: [1:0.50]
+; ATOM-NEXT:    retq # sched: [79:39.50]
+;
+; SLM-LABEL: test_fnop:
+; SLM:       # %bb.0:
+; SLM-NEXT:    xorps %xmm0, %xmm0 # sched: [1:0.50]
+; SLM-NEXT:    #APP
+; SLM-NEXT:    nop # sched: [1:?]
+; SLM-NEXT:    #NO_APP
+; SLM-NEXT:    retq # sched: [4:1.00]
+;
+; SANDY-LABEL: test_fnop:
+; SANDY:       # %bb.0:
+; SANDY-NEXT:    #APP
+; SANDY-NEXT:    nop # sched: [1:?]
+; SANDY-NEXT:    #NO_APP
+; SANDY-NEXT:    vxorps %xmm0, %xmm0, %xmm0 # sched: [1:1.00]
+; SANDY-NEXT:    retq # sched: [1:1.00]
+;
+; HASWELL-LABEL: test_fnop:
+; HASWELL:       # %bb.0:
+; HASWELL-NEXT:    #APP
+; HASWELL-NEXT:    nop # sched: [1:0.25]
+; HASWELL-NEXT:    #NO_APP
+; HASWELL-NEXT:    vxorps %xmm0, %xmm0, %xmm0 # sched: [1:1.00]
+; HASWELL-NEXT:    retq # sched: [7:1.00]
+;
+; BROADWELL-LABEL: test_fnop:
+; BROADWELL:       # %bb.0:
+; BROADWELL-NEXT:    #APP
+; BROADWELL-NEXT:    nop # sched: [1:0.25]
+; BROADWELL-NEXT:    #NO_APP
+; BROADWELL-NEXT:    vxorps %xmm0, %xmm0, %xmm0 # sched: [1:1.00]
+; BROADWELL-NEXT:    retq # sched: [7:1.00]
+;
+; SKYLAKE-LABEL: test_fnop:
+; SKYLAKE:       # %bb.0:
+; SKYLAKE-NEXT:    #APP
+; SKYLAKE-NEXT:    nop # sched: [1:0.25]
+; SKYLAKE-NEXT:    #NO_APP
+; SKYLAKE-NEXT:    vxorps %xmm0, %xmm0, %xmm0 # sched: [1:0.33]
+; SKYLAKE-NEXT:    retq # sched: [7:1.00]
+;
+; SKX-LABEL: test_fnop:
+; SKX:       # %bb.0:
+; SKX-NEXT:    #APP
+; SKX-NEXT:    nop # sched: [1:0.25]
+; SKX-NEXT:    #NO_APP
+; SKX-NEXT:    vxorps %xmm0, %xmm0, %xmm0 # sched: [1:0.33]
+; SKX-NEXT:    retq # sched: [7:1.00]
+;
+; BTVER2-LABEL: test_fnop:
+; BTVER2:       # %bb.0:
+; BTVER2-NEXT:    vxorps %xmm0, %xmm0, %xmm0 # sched: [1:0.50]
+; BTVER2-NEXT:    #APP
+; BTVER2-NEXT:    nop # sched: [1:?]
+; BTVER2-NEXT:    #NO_APP
+; BTVER2-NEXT:    retq # sched: [4:1.00]
+;
+; ZNVER1-LABEL: test_fnop:
+; ZNVER1:       # %bb.0:
+; ZNVER1-NEXT:    vxorps %xmm0, %xmm0, %xmm0 # sched: [1:0.25]
+; ZNVER1-NEXT:    #APP
+; ZNVER1-NEXT:    nop # sched: [1:?]
+; ZNVER1-NEXT:    #NO_APP
+; ZNVER1-NEXT:    retq # sched: [1:0.50]
+  tail call void asm sideeffect "nop", ""() nounwind
+  ret <4 x float> zeroinitializer
+}
+
 !0 = !{i32 1}