R600/SI: Fix using mad with multiplies by 2

These turn into fadds, so combine them into the target
mad node.

fadd (fadd (a, a), b) -> mad 2.0, a, b

llvm-svn: 218608

2 files changed, 187 insertions, 6 deletions

diff --git a/llvm/lib/Target/R600/SIISelLowering.cpp b/llvm/lib/Target/R600/SIISelLowering.cpp
index 417356d800f..10e6c17f6cc 100644
--- a/llvm/lib/Target/R600/SIISelLowering.cpp
+++ b/llvm/lib/Target/R600/SIISelLowering.cpp
@@ -226,6 +226,7 @@ SITargetLowering::SITargetLowering(TargetMachine &TM) :
 
   setOperationAction(ISD::FDIV, MVT::f32, Custom);
 
+  setTargetDAGCombine(ISD::FADD);
   setTargetDAGCombine(ISD::FSUB);
   setTargetDAGCombine(ISD::SELECT_CC);
   setTargetDAGCombine(ISD::SETCC);
@@ -1418,6 +1419,40 @@ SDValue SITargetLowering::PerformDAGCombine(SDNode *N,
   case ISD::UINT_TO_FP: {
     return performUCharToFloatCombine(N, DCI);
 
+  case ISD::FADD: {
+    if (DCI.getDAGCombineLevel() < AfterLegalizeDAG)
+      break;
+
+    EVT VT = N->getValueType(0);
+    if (VT != MVT::f32)
+      break;
+
+    SDValue LHS = N->getOperand(0);
+    SDValue RHS = N->getOperand(1);
+
+    // These should really be instruction patterns, but writing patterns with
+    // source modiifiers is a pain.
+
+    // fadd (fadd (a, a), b) -> mad 2.0, a, b
+    if (LHS.getOpcode() == ISD::FADD) {
+      SDValue A = LHS.getOperand(0);
+      if (A == LHS.getOperand(1)) {
+        const SDValue Two = DAG.getTargetConstantFP(2.0, MVT::f32);
+        return DAG.getNode(AMDGPUISD::MAD, DL, VT, Two, A, RHS);
+      }
+    }
+
+    // fadd (b, fadd (a, a)) -> mad 2.0, a, b
+    if (RHS.getOpcode() == ISD::FADD) {
+      SDValue A = RHS.getOperand(0);
+      if (A == RHS.getOperand(1)) {
+        const SDValue Two = DAG.getTargetConstantFP(2.0, MVT::f32);
+        return DAG.getNode(AMDGPUISD::MAD, DL, VT, Two, A, LHS);
+      }
+    }
+
+    break;
+  }
   case ISD::FSUB: {
     if (DCI.getDAGCombineLevel() < AfterLegalizeDAG)
       break;
diff --git a/llvm/test/CodeGen/R600/fmuladd.ll b/llvm/test/CodeGen/R600/fmuladd.ll
index 48944f62948..6f581f21d9b 100644
--- a/llvm/test/CodeGen/R600/fmuladd.ll
+++ b/llvm/test/CodeGen/R600/fmuladd.ll
@@ -1,6 +1,11 @@
-; RUN: llc < %s -march=r600 -mcpu=SI -verify-machineinstrs | FileCheck %s
+; RUN: llc -march=r600 -mcpu=SI -verify-machineinstrs < %s | FileCheck %s
 
-; CHECK: @fmuladd_f32
+declare float @llvm.fmuladd.f32(float, float, float)
+declare double @llvm.fmuladd.f64(double, double, double)
+declare i32 @llvm.r600.read.tidig.x() nounwind readnone
+declare float @llvm.fabs.f32(float) nounwind readnone
+
+; CHECK-LABEL: @fmuladd_f32
 ; CHECK: V_MAD_F32 {{v[0-9]+, v[0-9]+, v[0-9]+, v[0-9]+}}
 
 define void @fmuladd_f32(float addrspace(1)* %out, float addrspace(1)* %in1,
@@ -13,9 +18,7 @@ define void @fmuladd_f32(float addrspace(1)* %out, float addrspace(1)* %in1,
    ret void
 }
 
-declare float @llvm.fmuladd.f32(float, float, float)
-
-; CHECK: @fmuladd_f64
+; CHECK-LABEL: @fmuladd_f64
 ; CHECK: V_FMA_F64 {{v\[[0-9]+:[0-9]+\], v\[[0-9]+:[0-9]+\], v\[[0-9]+:[0-9]+\], v\[[0-9]+:[0-9]+\]}}
 
 define void @fmuladd_f64(double addrspace(1)* %out, double addrspace(1)* %in1,
@@ -28,4 +31,147 @@ define void @fmuladd_f64(double addrspace(1)* %out, double addrspace(1)* %in1,
    ret void
 }
 
-declare double @llvm.fmuladd.f64(double, double, double)
+; CHECK-LABEL: @fmuladd_2.0_a_b_f32
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R1:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64{{$}}
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R2:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:0x4
+; CHECK: V_MAD_F32 [[RESULT:v[0-9]+]], 2.0, [[R1]], [[R2]]
+; CHECK: BUFFER_STORE_DWORD [[RESULT]]
+define void @fmuladd_2.0_a_b_f32(float addrspace(1)* %out, float addrspace(1)* %in) {
+  %tid = call i32 @llvm.r600.read.tidig.x() nounwind readnone
+  %gep.0 = getelementptr float addrspace(1)* %out, i32 %tid
+  %gep.1 = getelementptr float addrspace(1)* %gep.0, i32 1
+  %gep.out = getelementptr float addrspace(1)* %out, i32 %tid
+
+  %r1 = load float addrspace(1)* %gep.0
+  %r2 = load float addrspace(1)* %gep.1
+
+  %r3 = tail call float @llvm.fmuladd.f32(float 2.0, float %r1, float %r2)
+  store float %r3, float addrspace(1)* %gep.out
+  ret void
+}
+
+; CHECK-LABEL: @fmuladd_a_2.0_b_f32
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R1:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64{{$}}
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R2:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:0x4
+; CHECK: V_MAD_F32 [[RESULT:v[0-9]+]], 2.0, [[R1]], [[R2]]
+; CHECK: BUFFER_STORE_DWORD [[RESULT]]
+define void @fmuladd_a_2.0_b_f32(float addrspace(1)* %out, float addrspace(1)* %in) {
+  %tid = call i32 @llvm.r600.read.tidig.x() nounwind readnone
+  %gep.0 = getelementptr float addrspace(1)* %out, i32 %tid
+  %gep.1 = getelementptr float addrspace(1)* %gep.0, i32 1
+  %gep.out = getelementptr float addrspace(1)* %out, i32 %tid
+
+  %r1 = load float addrspace(1)* %gep.0
+  %r2 = load float addrspace(1)* %gep.1
+
+  %r3 = tail call float @llvm.fmuladd.f32(float %r1, float 2.0, float %r2)
+  store float %r3, float addrspace(1)* %gep.out
+  ret void
+}
+
+; CHECK-LABEL: @fadd_a_a_b_f32
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R1:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64{{$}}
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R2:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:0x4
+; CHECK: V_MAD_F32 [[RESULT:v[0-9]+]], 2.0, [[R1]], [[R2]]
+; CHECK: BUFFER_STORE_DWORD [[RESULT]]
+define void @fadd_a_a_b_f32(float addrspace(1)* %out,
+                            float addrspace(1)* %in1,
+                            float addrspace(1)* %in2) {
+  %tid = call i32 @llvm.r600.read.tidig.x() nounwind readnone
+  %gep.0 = getelementptr float addrspace(1)* %out, i32 %tid
+  %gep.1 = getelementptr float addrspace(1)* %gep.0, i32 1
+  %gep.out = getelementptr float addrspace(1)* %out, i32 %tid
+
+  %r0 = load float addrspace(1)* %gep.0
+  %r1 = load float addrspace(1)* %gep.1
+
+  %add.0 = fadd float %r0, %r0
+  %add.1 = fadd float %add.0, %r1
+  store float %add.1, float addrspace(1)* %out
+  ret void
+}
+
+; CHECK-LABEL: @fadd_b_a_a_f32
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R1:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64{{$}}
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R2:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:0x4
+; CHECK: V_MAD_F32 [[RESULT:v[0-9]+]], 2.0, [[R1]], [[R2]]
+; CHECK: BUFFER_STORE_DWORD [[RESULT]]
+define void @fadd_b_a_a_f32(float addrspace(1)* %out,
+                            float addrspace(1)* %in1,
+                            float addrspace(1)* %in2) {
+  %tid = call i32 @llvm.r600.read.tidig.x() nounwind readnone
+  %gep.0 = getelementptr float addrspace(1)* %out, i32 %tid
+  %gep.1 = getelementptr float addrspace(1)* %gep.0, i32 1
+  %gep.out = getelementptr float addrspace(1)* %out, i32 %tid
+
+  %r0 = load float addrspace(1)* %gep.0
+  %r1 = load float addrspace(1)* %gep.1
+
+  %add.0 = fadd float %r0, %r0
+  %add.1 = fadd float %r1, %add.0
+  store float %add.1, float addrspace(1)* %out
+  ret void
+}
+
+; CHECK-LABEL: @fmuladd_neg_2.0_a_b_f32
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R1:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64{{$}}
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R2:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:0x4
+; CHECK: V_MAD_F32 [[RESULT:v[0-9]+]], [[R1]], -2.0, [[R2]]
+; CHECK: BUFFER_STORE_DWORD [[RESULT]]
+define void @fmuladd_neg_2.0_a_b_f32(float addrspace(1)* %out, float addrspace(1)* %in) {
+  %tid = call i32 @llvm.r600.read.tidig.x() nounwind readnone
+  %gep.0 = getelementptr float addrspace(1)* %out, i32 %tid
+  %gep.1 = getelementptr float addrspace(1)* %gep.0, i32 1
+  %gep.out = getelementptr float addrspace(1)* %out, i32 %tid
+
+  %r1 = load float addrspace(1)* %gep.0
+  %r2 = load float addrspace(1)* %gep.1
+
+  %r3 = tail call float @llvm.fmuladd.f32(float -2.0, float %r1, float %r2)
+  store float %r3, float addrspace(1)* %gep.out
+  ret void
+}
+
+
+; CHECK-LABEL: @fmuladd_neg_2.0_neg_a_b_f32
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R1:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64{{$}}
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R2:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:0x4
+; CHECK: V_MAD_F32 [[RESULT:v[0-9]+]], 2.0, [[R1]], [[R2]]
+; CHECK: BUFFER_STORE_DWORD [[RESULT]]
+define void @fmuladd_neg_2.0_neg_a_b_f32(float addrspace(1)* %out, float addrspace(1)* %in) {
+  %tid = call i32 @llvm.r600.read.tidig.x() nounwind readnone
+  %gep.0 = getelementptr float addrspace(1)* %out, i32 %tid
+  %gep.1 = getelementptr float addrspace(1)* %gep.0, i32 1
+  %gep.out = getelementptr float addrspace(1)* %out, i32 %tid
+
+  %r1 = load float addrspace(1)* %gep.0
+  %r2 = load float addrspace(1)* %gep.1
+
+  %r1.fneg = fsub float -0.000000e+00, %r1
+
+  %r3 = tail call float @llvm.fmuladd.f32(float -2.0, float %r1.fneg, float %r2)
+  store float %r3, float addrspace(1)* %gep.out
+  ret void
+}
+
+
+; CHECK-LABEL: @fmuladd_2.0_neg_a_b_f32
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R1:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64{{$}}
+; CHECK-DAG: BUFFER_LOAD_DWORD [[R2:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:0x4
+; CHECK: V_MAD_F32 [[RESULT:v[0-9]+]], [[R1]], -2.0, [[R2]]
+; CHECK: BUFFER_STORE_DWORD [[RESULT]]
+define void @fmuladd_2.0_neg_a_b_f32(float addrspace(1)* %out, float addrspace(1)* %in) {
+  %tid = call i32 @llvm.r600.read.tidig.x() nounwind readnone
+  %gep.0 = getelementptr float addrspace(1)* %out, i32 %tid
+  %gep.1 = getelementptr float addrspace(1)* %gep.0, i32 1
+  %gep.out = getelementptr float addrspace(1)* %out, i32 %tid
+
+  %r1 = load float addrspace(1)* %gep.0
+  %r2 = load float addrspace(1)* %gep.1
+
+  %r1.fneg = fsub float -0.000000e+00, %r1
+
+  %r3 = tail call float @llvm.fmuladd.f32(float 2.0, float %r1.fneg, float %r2)
+  store float %r3, float addrspace(1)* %gep.out
+  ret void
+}