AMDGPU: Reduce cost of f64 copysign

The real implementation is 1 real instruction plus a constant
materialize. Call that a 1, it's not a real f64 operation.

Author: arsenm

llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp

@@ -718,9 +718,6 @@ GCNTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
 
   MVT::SimpleValueType SLT = LT.second.getScalarType().SimpleTy;
 
-  if (SLT == MVT::f64)
-    return LT.first * NElts * get64BitInstrCost(CostKind);
-
   if ((ST->hasVOP3PInsts() && (SLT == MVT::f16 || SLT == MVT::i16)) ||
       (ST->hasPackedFP32Ops() && SLT == MVT::f32))
     NElts = (NElts + 1) / 2;
@@ -731,6 +728,11 @@ GCNTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
   switch (ICA.getID()) {
   case Intrinsic::fma:
   case Intrinsic::fmuladd:
+    if (SLT == MVT::f64) {
+      InstRate = get64BitInstrCost(CostKind);
+      break;
+    }
+
     if ((SLT == MVT::f32 && ST->hasFastFMAF32()) || SLT == MVT::f16)
       InstRate = getFullRateInstrCost();
     else {
@@ -741,8 +743,8 @@ GCNTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
   case Intrinsic::copysign:
     return NElts * getFullRateInstrCost();
   case Intrinsic::canonicalize: {
-    assert(SLT != MVT::f64);
-    InstRate = getFullRateInstrCost();
+    InstRate =
+        SLT == MVT::f64 ? get64BitInstrCost(CostKind) : getFullRateInstrCost();
     break;
   }
   case Intrinsic::uadd_sat:

llvm/test/Analysis/CostModel/AMDGPU/copysign.ll

@@ -245,25 +245,25 @@ define void @copysign_bf16() {
 
 define void @copysign_f64() {
 ; ALL-LABEL: 'copysign_f64'
-; ALL-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %f64 = call double @llvm.copysign.f64(double undef, double undef)
-; ALL-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %v2f64 = call <2 x double> @llvm.copysign.v2f64(<2 x double> undef, <2 x double> undef)
-; ALL-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %v3f64 = call <3 x double> @llvm.copysign.v3f64(<3 x double> undef, <3 x double> undef)
-; ALL-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %v4f64 = call <4 x double> @llvm.copysign.v4f64(<4 x double> undef, <4 x double> undef)
-; ALL-NEXT:  Cost Model: Found an estimated cost of 96 for instruction: %v5f64 = call <5 x double> @llvm.copysign.v5f64(<5 x double> undef, <5 x double> undef)
-; ALL-NEXT:  Cost Model: Found an estimated cost of 96 for instruction: %v8f64 = call <8 x double> @llvm.copysign.v8f64(<8 x double> undef, <8 x double> undef)
-; ALL-NEXT:  Cost Model: Found an estimated cost of 256 for instruction: %v9f64 = call <9 x double> @llvm.copysign.v9f64(<9 x double> undef, <9 x double> undef)
-; ALL-NEXT:  Cost Model: Found an estimated cost of 320 for instruction: %v16f64 = call <16 x double> @llvm.copysign.v16f64(<16 x double> undef, <16 x double> undef)
+; ALL-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %f64 = call double @llvm.copysign.f64(double undef, double undef)
+; ALL-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v2f64 = call <2 x double> @llvm.copysign.v2f64(<2 x double> undef, <2 x double> undef)
+; ALL-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %v3f64 = call <3 x double> @llvm.copysign.v3f64(<3 x double> undef, <3 x double> undef)
+; ALL-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %v4f64 = call <4 x double> @llvm.copysign.v4f64(<4 x double> undef, <4 x double> undef)
+; ALL-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %v5f64 = call <5 x double> @llvm.copysign.v5f64(<5 x double> undef, <5 x double> undef)
+; ALL-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %v8f64 = call <8 x double> @llvm.copysign.v8f64(<8 x double> undef, <8 x double> undef)
+; ALL-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %v9f64 = call <9 x double> @llvm.copysign.v9f64(<9 x double> undef, <9 x double> undef)
+; ALL-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %v16f64 = call <16 x double> @llvm.copysign.v16f64(<16 x double> undef, <16 x double> undef)
 ; ALL-NEXT:  Cost Model: Found an estimated cost of 10 for instruction: ret void
 ;
 ; ALL-SIZE-LABEL: 'copysign_f64'
-; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %f64 = call double @llvm.copysign.f64(double undef, double undef)
-; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %v2f64 = call <2 x double> @llvm.copysign.v2f64(<2 x double> undef, <2 x double> undef)
-; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %v3f64 = call <3 x double> @llvm.copysign.v3f64(<3 x double> undef, <3 x double> undef)
-; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %v4f64 = call <4 x double> @llvm.copysign.v4f64(<4 x double> undef, <4 x double> undef)
-; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 48 for instruction: %v5f64 = call <5 x double> @llvm.copysign.v5f64(<5 x double> undef, <5 x double> undef)
-; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 48 for instruction: %v8f64 = call <8 x double> @llvm.copysign.v8f64(<8 x double> undef, <8 x double> undef)
-; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 128 for instruction: %v9f64 = call <9 x double> @llvm.copysign.v9f64(<9 x double> undef, <9 x double> undef)
-; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 160 for instruction: %v16f64 = call <16 x double> @llvm.copysign.v16f64(<16 x double> undef, <16 x double> undef)
+; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %f64 = call double @llvm.copysign.f64(double undef, double undef)
+; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v2f64 = call <2 x double> @llvm.copysign.v2f64(<2 x double> undef, <2 x double> undef)
+; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %v3f64 = call <3 x double> @llvm.copysign.v3f64(<3 x double> undef, <3 x double> undef)
+; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %v4f64 = call <4 x double> @llvm.copysign.v4f64(<4 x double> undef, <4 x double> undef)
+; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %v5f64 = call <5 x double> @llvm.copysign.v5f64(<5 x double> undef, <5 x double> undef)
+; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %v8f64 = call <8 x double> @llvm.copysign.v8f64(<8 x double> undef, <8 x double> undef)
+; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %v9f64 = call <9 x double> @llvm.copysign.v9f64(<9 x double> undef, <9 x double> undef)
+; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %v16f64 = call <16 x double> @llvm.copysign.v16f64(<16 x double> undef, <16 x double> undef)
 ; ALL-SIZE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret void
 ;
   %f64 = call double @llvm.copysign.f64(double undef, double undef)