[RISCV] Add cost model for fma (llvm#126076)

This change builds on PR llvm#125683, which added a cost model for fmuladd.

To ensure completeness, this patch extends the cost model to also cover fma, using the same costing approach as fmuladd.

I plan to send a follow-up patch that includes the cost model vp_fma and vp_fmuladd, and their tests.

Author: mikhailramalho

llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp

@@ -1176,6 +1176,7 @@ RISCVTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
     }
     break;
   }
+  case Intrinsic::fma:
   case Intrinsic::fmuladd: {
     // TODO: handle promotion with f16/bf16 with zvfhmin/zvfbfmin
     auto LT = getTypeLegalizationCost(RetTy);

llvm/test/Analysis/CostModel/RISCV/arith-fp.ll

@@ -1381,30 +1381,30 @@ define void @fma() {
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2BF16 = call <2 x bfloat> @llvm.fma.v2bf16(<2 x bfloat> undef, <2 x bfloat> undef, <2 x bfloat> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4BF16 = call <4 x bfloat> @llvm.fma.v4bf16(<4 x bfloat> undef, <4 x bfloat> undef, <4 x bfloat> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8BF16 = call <8 x bfloat> @llvm.fma.v8bf16(<8 x bfloat> undef, <8 x bfloat> undef, <8 x bfloat> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V16BF16 = call <16 x bfloat> @llvm.fma.v16bf16(<16 x bfloat> undef, <16 x bfloat> undef, <16 x bfloat> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16BF16 = call <16 x bfloat> @llvm.fma.v16bf16(<16 x bfloat> undef, <16 x bfloat> undef, <16 x bfloat> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV1BF16 = call <vscale x 1 x bfloat> @llvm.fma.nxv1bf16(<vscale x 1 x bfloat> undef, <vscale x 1 x bfloat> undef, <vscale x 1 x bfloat> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV2BF16 = call <vscale x 2 x bfloat> @llvm.fma.nxv2bf16(<vscale x 2 x bfloat> undef, <vscale x 2 x bfloat> undef, <vscale x 2 x bfloat> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV4BF16 = call <vscale x 4 x bfloat> @llvm.fma.nxv4bf16(<vscale x 4 x bfloat> undef, <vscale x 4 x bfloat> undef, <vscale x 4 x bfloat> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV8BF16 = call <vscale x 8 x bfloat> @llvm.fma.nxv8bf16(<vscale x 8 x bfloat> undef, <vscale x 8 x bfloat> undef, <vscale x 8 x bfloat> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV16BF16 = call <vscale x 16 x bfloat> @llvm.fma.nxv16bf16(<vscale x 16 x bfloat> undef, <vscale x 16 x bfloat> undef, <vscale x 16 x bfloat> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V1F32 = call <1 x float> @llvm.fma.v1f32(<1 x float> undef, <1 x float> undef, <1 x float> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2F32 = call <2 x float> @llvm.fma.v2f32(<2 x float> undef, <2 x float> undef, <2 x float> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4F32 = call <4 x float> @llvm.fma.v4f32(<4 x float> undef, <4 x float> undef, <4 x float> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %NXV8BF16 = call <vscale x 8 x bfloat> @llvm.fma.nxv8bf16(<vscale x 8 x bfloat> undef, <vscale x 8 x bfloat> undef, <vscale x 8 x bfloat> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %NXV16BF16 = call <vscale x 16 x bfloat> @llvm.fma.nxv16bf16(<vscale x 16 x bfloat> undef, <vscale x 16 x bfloat> undef, <vscale x 16 x bfloat> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V1F32 = call <1 x float> @llvm.fma.v1f32(<1 x float> undef, <1 x float> undef, <1 x float> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2F32 = call <2 x float> @llvm.fma.v2f32(<2 x float> undef, <2 x float> undef, <2 x float> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4F32 = call <4 x float> @llvm.fma.v4f32(<4 x float> undef, <4 x float> undef, <4 x float> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8F32 = call <8 x float> @llvm.fma.v8f32(<8 x float> undef, <8 x float> undef, <8 x float> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16F32 = call <16 x float> @llvm.fma.v16f32(<16 x float> undef, <16 x float> undef, <16 x float> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V16F32 = call <16 x float> @llvm.fma.v16f32(<16 x float> undef, <16 x float> undef, <16 x float> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV1F32 = call <vscale x 1 x float> @llvm.fma.nxv1f32(<vscale x 1 x float> undef, <vscale x 1 x float> undef, <vscale x 1 x float> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV2F32 = call <vscale x 2 x float> @llvm.fma.nxv2f32(<vscale x 2 x float> undef, <vscale x 2 x float> undef, <vscale x 2 x float> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV4F32 = call <vscale x 4 x float> @llvm.fma.nxv4f32(<vscale x 4 x float> undef, <vscale x 4 x float> undef, <vscale x 4 x float> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV8F32 = call <vscale x 8 x float> @llvm.fma.nxv8f32(<vscale x 8 x float> undef, <vscale x 8 x float> undef, <vscale x 8 x float> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV16F32 = call <vscale x 16 x float> @llvm.fma.nxv16f32(<vscale x 16 x float> undef, <vscale x 16 x float> undef, <vscale x 16 x float> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V1F64 = call <1 x double> @llvm.fma.v1f64(<1 x double> undef, <1 x double> undef, <1 x double> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2F64 = call <2 x double> @llvm.fma.v2f64(<2 x double> undef, <2 x double> undef, <2 x double> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %NXV4F32 = call <vscale x 4 x float> @llvm.fma.nxv4f32(<vscale x 4 x float> undef, <vscale x 4 x float> undef, <vscale x 4 x float> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %NXV8F32 = call <vscale x 8 x float> @llvm.fma.nxv8f32(<vscale x 8 x float> undef, <vscale x 8 x float> undef, <vscale x 8 x float> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %NXV16F32 = call <vscale x 16 x float> @llvm.fma.nxv16f32(<vscale x 16 x float> undef, <vscale x 16 x float> undef, <vscale x 16 x float> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V1F64 = call <1 x double> @llvm.fma.v1f64(<1 x double> undef, <1 x double> undef, <1 x double> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2F64 = call <2 x double> @llvm.fma.v2f64(<2 x double> undef, <2 x double> undef, <2 x double> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4F64 = call <4 x double> @llvm.fma.v4f64(<4 x double> undef, <4 x double> undef, <4 x double> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8F64 = call <8 x double> @llvm.fma.v8f64(<8 x double> undef, <8 x double> undef, <8 x double> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V8F64 = call <8 x double> @llvm.fma.v8f64(<8 x double> undef, <8 x double> undef, <8 x double> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV1F64 = call <vscale x 1 x double> @llvm.fma.nxv1f64(<vscale x 1 x double> undef, <vscale x 1 x double> undef, <vscale x 1 x double> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV2F64 = call <vscale x 2 x double> @llvm.fma.nxv2f64(<vscale x 2 x double> undef, <vscale x 2 x double> undef, <vscale x 2 x double> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV4F64 = call <vscale x 4 x double> @llvm.fma.nxv4f64(<vscale x 4 x double> undef, <vscale x 4 x double> undef, <vscale x 4 x double> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV8F64 = call <vscale x 8 x double> @llvm.fma.nxv8f64(<vscale x 8 x double> undef, <vscale x 8 x double> undef, <vscale x 8 x double> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %NXV2F64 = call <vscale x 2 x double> @llvm.fma.nxv2f64(<vscale x 2 x double> undef, <vscale x 2 x double> undef, <vscale x 2 x double> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %NXV4F64 = call <vscale x 4 x double> @llvm.fma.nxv4f64(<vscale x 4 x double> undef, <vscale x 4 x double> undef, <vscale x 4 x double> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %NXV8F64 = call <vscale x 8 x double> @llvm.fma.nxv8f64(<vscale x 8 x double> undef, <vscale x 8 x double> undef, <vscale x 8 x double> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
   %BF16 = call bfloat @llvm.fma.bf16(bfloat undef, bfloat undef, bfloat undef)
@@ -1449,37 +1449,21 @@ define void @fma() {
 }
 
 define void @fma_f16() {
-; ZVFH-LABEL: 'fma_f16'
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %F16 = call half @llvm.fma.f16(half undef, half undef, half undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V1F16 = call <1 x half> @llvm.fma.v1f16(<1 x half> undef, <1 x half> undef, <1 x half> undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2F16 = call <2 x half> @llvm.fma.v2f16(<2 x half> undef, <2 x half> undef, <2 x half> undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4F16 = call <4 x half> @llvm.fma.v4f16(<4 x half> undef, <4 x half> undef, <4 x half> undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8F16 = call <8 x half> @llvm.fma.v8f16(<8 x half> undef, <8 x half> undef, <8 x half> undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16F16 = call <16 x half> @llvm.fma.v16f16(<16 x half> undef, <16 x half> undef, <16 x half> undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V32F16 = call <32 x half> @llvm.fma.v32f16(<32 x half> undef, <32 x half> undef, <32 x half> undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV1F16 = call <vscale x 1 x half> @llvm.fma.nxv1f16(<vscale x 1 x half> undef, <vscale x 1 x half> undef, <vscale x 1 x half> undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV2F16 = call <vscale x 2 x half> @llvm.fma.nxv2f16(<vscale x 2 x half> undef, <vscale x 2 x half> undef, <vscale x 2 x half> undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV4F16 = call <vscale x 4 x half> @llvm.fma.nxv4f16(<vscale x 4 x half> undef, <vscale x 4 x half> undef, <vscale x 4 x half> undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV8F16 = call <vscale x 8 x half> @llvm.fma.nxv8f16(<vscale x 8 x half> undef, <vscale x 8 x half> undef, <vscale x 8 x half> undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV16F16 = call <vscale x 16 x half> @llvm.fma.nxv16f16(<vscale x 16 x half> undef, <vscale x 16 x half> undef, <vscale x 16 x half> undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV32F16 = call <vscale x 32 x half> @llvm.fma.nxv32f16(<vscale x 32 x half> undef, <vscale x 32 x half> undef, <vscale x 32 x half> undef)
-; ZVFH-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
-;
-; ZVFHMIN-LABEL: 'fma_f16'
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %F16 = call half @llvm.fma.f16(half undef, half undef, half undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V1F16 = call <1 x half> @llvm.fma.v1f16(<1 x half> undef, <1 x half> undef, <1 x half> undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2F16 = call <2 x half> @llvm.fma.v2f16(<2 x half> undef, <2 x half> undef, <2 x half> undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4F16 = call <4 x half> @llvm.fma.v4f16(<4 x half> undef, <4 x half> undef, <4 x half> undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8F16 = call <8 x half> @llvm.fma.v8f16(<8 x half> undef, <8 x half> undef, <8 x half> undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V16F16 = call <16 x half> @llvm.fma.v16f16(<16 x half> undef, <16 x half> undef, <16 x half> undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V32F16 = call <32 x half> @llvm.fma.v32f16(<32 x half> undef, <32 x half> undef, <32 x half> undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV1F16 = call <vscale x 1 x half> @llvm.fma.nxv1f16(<vscale x 1 x half> undef, <vscale x 1 x half> undef, <vscale x 1 x half> undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV2F16 = call <vscale x 2 x half> @llvm.fma.nxv2f16(<vscale x 2 x half> undef, <vscale x 2 x half> undef, <vscale x 2 x half> undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV4F16 = call <vscale x 4 x half> @llvm.fma.nxv4f16(<vscale x 4 x half> undef, <vscale x 4 x half> undef, <vscale x 4 x half> undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV8F16 = call <vscale x 8 x half> @llvm.fma.nxv8f16(<vscale x 8 x half> undef, <vscale x 8 x half> undef, <vscale x 8 x half> undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV16F16 = call <vscale x 16 x half> @llvm.fma.nxv16f16(<vscale x 16 x half> undef, <vscale x 16 x half> undef, <vscale x 16 x half> undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %NXV32F16 = call <vscale x 32 x half> @llvm.fma.nxv32f16(<vscale x 32 x half> undef, <vscale x 32 x half> undef, <vscale x 32 x half> undef)
-; ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
+; CHECK-LABEL: 'fma_f16'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %F16 = call half @llvm.fma.f16(half undef, half undef, half undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V1F16 = call <1 x half> @llvm.fma.v1f16(<1 x half> undef, <1 x half> undef, <1 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2F16 = call <2 x half> @llvm.fma.v2f16(<2 x half> undef, <2 x half> undef, <2 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4F16 = call <4 x half> @llvm.fma.v4f16(<4 x half> undef, <4 x half> undef, <4 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8F16 = call <8 x half> @llvm.fma.v8f16(<8 x half> undef, <8 x half> undef, <8 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16F16 = call <16 x half> @llvm.fma.v16f16(<16 x half> undef, <16 x half> undef, <16 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V32F16 = call <32 x half> @llvm.fma.v32f16(<32 x half> undef, <32 x half> undef, <32 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV1F16 = call <vscale x 1 x half> @llvm.fma.nxv1f16(<vscale x 1 x half> undef, <vscale x 1 x half> undef, <vscale x 1 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV2F16 = call <vscale x 2 x half> @llvm.fma.nxv2f16(<vscale x 2 x half> undef, <vscale x 2 x half> undef, <vscale x 2 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %NXV4F16 = call <vscale x 4 x half> @llvm.fma.nxv4f16(<vscale x 4 x half> undef, <vscale x 4 x half> undef, <vscale x 4 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %NXV8F16 = call <vscale x 8 x half> @llvm.fma.nxv8f16(<vscale x 8 x half> undef, <vscale x 8 x half> undef, <vscale x 8 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %NXV16F16 = call <vscale x 16 x half> @llvm.fma.nxv16f16(<vscale x 16 x half> undef, <vscale x 16 x half> undef, <vscale x 16 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %NXV32F16 = call <vscale x 32 x half> @llvm.fma.nxv32f16(<vscale x 32 x half> undef, <vscale x 32 x half> undef, <vscale x 32 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
   %F16 = call half @llvm.fma.f16(half undef, half undef, half undef)