TTI: Estimate @llvm.fmuladd cost as fmul + fadd when FMA's aren't legal on the target.
llvm-svn: 208115
diff --git a/llvm/lib/CodeGen/BasicTargetTransformInfo.cpp b/llvm/lib/CodeGen/BasicTargetTransformInfo.cpp
index 6ad1f28..4b89509 100644
--- a/llvm/lib/CodeGen/BasicTargetTransformInfo.cpp
+++ b/llvm/lib/CodeGen/BasicTargetTransformInfo.cpp
@@ -487,7 +487,7 @@
case Intrinsic::round: ISD = ISD::FROUND; break;
case Intrinsic::pow: ISD = ISD::FPOW; break;
case Intrinsic::fma: ISD = ISD::FMA; break;
- case Intrinsic::fmuladd: ISD = ISD::FMA; break; // FIXME: mul + add?
+ case Intrinsic::fmuladd: ISD = ISD::FMA; break;
case Intrinsic::lifetime_start:
case Intrinsic::lifetime_end:
return 0;
@@ -512,6 +512,12 @@
return LT.first * 2;
}
+ // If we can't lower fmuladd into an FMA estimate the cost as a floating
+ // point mul followed by an add.
+ if (IID == Intrinsic::fmuladd)
+ return TopTTI->getArithmeticInstrCost(BinaryOperator::FMul, RetTy) +
+ TopTTI->getArithmeticInstrCost(BinaryOperator::FAdd, RetTy);
+
// Else, assume that we need to scalarize this intrinsic. For math builtins
// this will emit a costly libcall, adding call overhead and spills. Make it
// very expensive.
diff --git a/llvm/test/Analysis/CostModel/X86/intrinsic-cost.ll b/llvm/test/Analysis/CostModel/X86/intrinsic-cost.ll
index 8eeee81..3b27b52 100644
--- a/llvm/test/Analysis/CostModel/X86/intrinsic-cost.ll
+++ b/llvm/test/Analysis/CostModel/X86/intrinsic-cost.ll
@@ -58,3 +58,31 @@
}
declare <4 x float> @llvm.nearbyint.v4f32(<4 x float>) nounwind readnone
+
+define void @test3(float* nocapture %f, <4 x float> %b, <4 x float> %c) nounwind {
+vector.ph:
+ br label %vector.body
+
+vector.body: ; preds = %vector.body, %vector.ph
+ %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+ %0 = getelementptr inbounds float* %f, i64 %index
+ %1 = bitcast float* %0 to <4 x float>*
+ %wide.load = load <4 x float>* %1, align 4
+ %2 = call <4 x float> @llvm.fmuladd.v4f32(<4 x float> %wide.load, <4 x float> %b, <4 x float> %c)
+ store <4 x float> %2, <4 x float>* %1, align 4
+ %index.next = add i64 %index, 4
+ %3 = icmp eq i64 %index.next, 1024
+ br i1 %3, label %for.end, label %vector.body
+
+for.end: ; preds = %vector.body
+ ret void
+
+; CORE2: Printing analysis 'Cost Model Analysis' for function 'test3':
+; CORE2: Cost Model: Found an estimated cost of 4 for instruction: %2 = call <4 x float> @llvm.fmuladd.v4f32(<4 x float> %wide.load, <4 x float> %b, <4 x float> %c)
+
+; COREI7: Printing analysis 'Cost Model Analysis' for function 'test3':
+; COREI7: Cost Model: Found an estimated cost of 4 for instruction: %2 = call <4 x float> @llvm.fmuladd.v4f32(<4 x float> %wide.load, <4 x float> %b, <4 x float> %c)
+
+}
+
+declare <4 x float> @llvm.fmuladd.v4f32(<4 x float>, <4 x float>, <4 x float>) nounwind readnone