[PATCH] D50324: AMDGPU: Match isfinite pattern to class instructions

[Matt Arsenault via Phabricator via llvm-commits]

arsenm created this revision.
arsenm added a reviewer: b-sumner.
Herald added subscribers: t-tye, tpr, dstuttard, yaxunl, nhaehnle, wdng, kzhuravl.

https://reviews.llvm.org/D50324

Files:
  lib/Target/AMDGPU/SIISelLowering.cpp
  test/CodeGen/AMDGPU/fp-classify.ll


Index: test/CodeGen/AMDGPU/fp-classify.ll
===================================================================
--- test/CodeGen/AMDGPU/fp-classify.ll
+++ test/CodeGen/AMDGPU/fp-classify.ll
@@ -55,6 +55,20 @@
   ret void
 }
 
+; SI-LABEL: {{^}}test_isfinite_pattern_1:
+; SI-NOT: v_cmp
+; SI: v_mov_b32_e32 [[MASK:v[0-9]+]], 0x1f8{{$}}
+; SI: v_cmp_class_f32_e32 vcc, s{{[0-9]+}}, [[MASK]]
+; SI-NOT: v_cmp
+; SI: s_endpgm
+define amdgpu_kernel void @test_isfinite_pattern_1(i32 addrspace(1)* nocapture %out, float %x) #0 {
+  %x.fabs = tail call float @llvm.fabs.f32(float %x) #3
+  %cmpinf = fcmp one float %x.fabs, 0x7FF0000000000000
+  %ext = zext i1 %cmpinf to i32
+  store i32 %ext, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
 ; Use negative infinity
 ; GCN-LABEL: {{^}}test_isfinite_not_pattern_0:
 ; GCN-NOT: v_cmp_class_f32
@@ -111,10 +125,14 @@
 }
 
 ; Wrong unordered compare
-; GCN-LABEL: {{^}}test_isfinite_not_pattern_4:
-; GCN-NOT: v_cmp_class_f32
-; GCN: s_endpgm
-define amdgpu_kernel void @test_isfinite_not_pattern_4(i32 addrspace(1)* nocapture %out, float %x) #0 {
+; GCN-LABEL: {{^}}test_isfinite_pattern_4:
+; GCN-DAG: s_load_dword [[X:s[0-9]+]]
+; GCN-DAG: v_mov_b32_e32 [[K:v[0-9]+]], 0x1f8
+; GCN-DAG: v_cmp_o_f32_e64 [[ORD:s\[[0-9]+:[0-9]+\]]], [[X]], [[X]]
+; GCN-DAG: v_cmp_class_f32_e32 vcc, [[X]], [[K]]
+; GCN: s_and_b64 [[AND:s\[[0-9]+:[0-9]+\]]], [[ORD]], vcc
+; GCN: v_cndmask_b32_e64 v{{[0-9]+}}, 0, 1, [[AND]]
+define amdgpu_kernel void @test_isfinite_pattern_4(i32 addrspace(1)* nocapture %out, float %x) #0 {
   %ord = fcmp ord float %x, 0.000000e+00
   %x.fabs = tail call float @llvm.fabs.f32(float %x) #1
   %ninf = fcmp one float %x.fabs, 0x7FF0000000000000
Index: lib/Target/AMDGPU/SIISelLowering.cpp
===================================================================
--- lib/Target/AMDGPU/SIISelLowering.cpp
+++ lib/Target/AMDGPU/SIISelLowering.cpp
@@ -7804,16 +7804,26 @@
                                            VT != MVT::f16))
     return SDValue();
 
-  // Match isinf pattern
+  // Match isinf/isfinite pattern
   // (fcmp oeq (fabs x), inf) -> (fp_class x, (p_infinity | n_infinity))
-  if (CC == ISD::SETOEQ && LHS.getOpcode() == ISD::FABS) {
+  // (fcmp one (fabs x), inf) -> (fp_class x,
+  // (p_normal | n_normal | p_subnormal | n_subnormal | p_zero | n_zero)
+  if ((CC == ISD::SETOEQ || CC == ISD::SETONE) && LHS.getOpcode() == ISD::FABS) {
     const ConstantFPSDNode *CRHS = dyn_cast<ConstantFPSDNode>(RHS);
     if (!CRHS)
       return SDValue();
 
     const APFloat &APF = CRHS->getValueAPF();
     if (APF.isInfinity() && !APF.isNegative()) {
-      unsigned Mask = SIInstrFlags::P_INFINITY | SIInstrFlags::N_INFINITY;
+      const unsigned IsInfMask = SIInstrFlags::P_INFINITY |
+                                 SIInstrFlags::N_INFINITY;
+      const unsigned IsFiniteMask = SIInstrFlags::N_ZERO |
+                                    SIInstrFlags::P_ZERO |
+                                    SIInstrFlags::N_NORMAL |
+                                    SIInstrFlags::P_NORMAL |
+                                    SIInstrFlags::N_SUBNORMAL |
+                                    SIInstrFlags::P_SUBNORMAL;
+      unsigned Mask = CC == ISD::SETOEQ ? IsInfMask : IsFiniteMask;
       return DAG.getNode(AMDGPUISD::FP_CLASS, SL, MVT::i1, LHS.getOperand(0),
                          DAG.getConstant(Mask, SL, MVT::i32));
     }


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