[PATCH] D97470: [CostModel] Align the cost model for intrinsics for scalable/fixed-width vectors.

[Sander de Smalen via Phabricator via llvm-commits]

sdesmalen created this revision.
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Let getIntrinsicInstrCost call getTypeBasedIntrinsicInstrCost for scalable vectors,
similar to how this is done for fixed-width vectors, instead of falling back
on BaseT::getIntrinsicInstrCost().

If the intrinsic cannot be costed (or is not overloaded by the target),
it will return InstructionCost::getInvalid() instead.

Depends on D97469 <https://reviews.llvm.org/D97469>


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D97470

Files:
  llvm/include/llvm/CodeGen/BasicTTIImpl.h
  llvm/test/Analysis/CostModel/AArch64/sve-getIntrinsicInstrCost-cctz-ctlz.ll
  llvm/test/Analysis/CostModel/AArch64/sve-math.ll


Index: llvm/test/Analysis/CostModel/AArch64/sve-math.ll
===================================================================
--- llvm/test/Analysis/CostModel/AArch64/sve-math.ll
+++ llvm/test/Analysis/CostModel/AArch64/sve-math.ll
@@ -29,7 +29,7 @@
 
 define <vscale x 2 x double> @sqrt_v2f64(<vscale x 2 x double> %a) {
 ; THRU-LABEL: 'sqrt_v2f64'
-; THRU-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %r = call <vscale x 2 x double> @llvm.sqrt.nxv2f64(<vscale x 2 x double> %a)
+; THRU-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %r = call <vscale x 2 x double> @llvm.sqrt.nxv2f64(<vscale x 2 x double> %a)
 ; THRU-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <vscale x 2 x double> %r
 ;
 ; LATE-LABEL: 'sqrt_v2f64'
@@ -37,11 +37,11 @@
 ; LATE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret <vscale x 2 x double> %r
 ;
 ; SIZE-LABEL: 'sqrt_v2f64'
-; SIZE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %r = call <vscale x 2 x double> @llvm.sqrt.nxv2f64(<vscale x 2 x double> %a)
+; SIZE-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %r = call <vscale x 2 x double> @llvm.sqrt.nxv2f64(<vscale x 2 x double> %a)
 ; SIZE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret <vscale x 2 x double> %r
 ;
 ; SIZE_LATE-LABEL: 'sqrt_v2f64'
-; SIZE_LATE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %r = call <vscale x 2 x double> @llvm.sqrt.nxv2f64(<vscale x 2 x double> %a)
+; SIZE_LATE-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %r = call <vscale x 2 x double> @llvm.sqrt.nxv2f64(<vscale x 2 x double> %a)
 ; SIZE_LATE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret <vscale x 2 x double> %r
 ;
   %r = call <vscale x 2 x double> @llvm.sqrt.v2f64(<vscale x 2 x double> %a)
Index: llvm/test/Analysis/CostModel/AArch64/sve-getIntrinsicInstrCost-cctz-ctlz.ll
===================================================================
--- llvm/test/Analysis/CostModel/AArch64/sve-getIntrinsicInstrCost-cctz-ctlz.ll
+++ llvm/test/Analysis/CostModel/AArch64/sve-getIntrinsicInstrCost-cctz-ctlz.ll
@@ -11,7 +11,7 @@
 
 define void  @ctlz_nxv4i32(<vscale x 4 x i32> %A) {
 ; CHECK-LABEL: 'ctlz_nxv4i32'
-; CHECK-NEXT: Cost Model: Found an estimated cost of 1 for instruction:   %1 = tail call <vscale x 4 x i32> @llvm.ctlz.nxv4i32(<vscale x 4 x i32> %A, i1 true)
+; CHECK-NEXT: Cost Model: Found an estimated cost of 2 for instruction:   %1 = tail call <vscale x 4 x i32> @llvm.ctlz.nxv4i32(<vscale x 4 x i32> %A, i1 true)
 ; CHECK-NEXT: Cost Model: Found an estimated cost of 0 for instruction:   ret void
 
   %1 = tail call <vscale x 4 x i32> @llvm.ctlz.nxv4i32(<vscale x 4 x i32> %A, i1 true)
@@ -22,7 +22,7 @@
 
 define void  @cttz_nxv4i32(<vscale x 4 x i32> %A) {
 ; CHECK-LABEL: 'cttz_nxv4i32'
-; CHECK-NEXT: Cost Model: Found an estimated cost of 1 for instruction:   %1 = tail call <vscale x 4 x i32> @llvm.cttz.nxv4i32(<vscale x 4 x i32> %A, i1 true)
+; CHECK-NEXT: Cost Model: Found an estimated cost of 2 for instruction:   %1 = tail call <vscale x 4 x i32> @llvm.cttz.nxv4i32(<vscale x 4 x i32> %A, i1 true)
 ; CHECK-NEXT: Cost Model: Found an estimated cost of 0 for instruction:   ret void
 
   %1 = tail call <vscale x 4 x i32> @llvm.cttz.nxv4i32(<vscale x 4 x i32> %A, i1 true)
Index: llvm/include/llvm/CodeGen/BasicTTIImpl.h
===================================================================
--- llvm/include/llvm/CodeGen/BasicTTIImpl.h
+++ llvm/include/llvm/CodeGen/BasicTTIImpl.h
@@ -1338,15 +1338,12 @@
       return Cost;
     }
     }
-    // TODO: Handle the remaining intrinsic with scalable vector type
-    if (isa<ScalableVectorType>(RetTy))
-      return BaseT::getIntrinsicInstrCost(ICA, CostKind);
 
     // Assume that we need to scalarize this intrinsic.
     // Compute the scalarization overhead based on Args for a vector
     // intrinsic.
     unsigned ScalarizationCost = std::numeric_limits<unsigned>::max();
-    if (RetVF.isVector()) {
+    if (RetVF.isVector() && !RetVF.isScalable()) {
       ScalarizationCost = 0;
       if (!RetTy->isVoidTy())
         ScalarizationCost +=
@@ -1391,6 +1388,11 @@
     SmallVector<unsigned, 2> ISDs;
     switch (IID) {
     default: {
+      // Scalable vectors cannot be scalarized, so return Invalid.
+      if (isa<ScalableVectorType>(RetTy) ||
+          any_of(Tys, [](const Type *Ty) { return isa<ScalableVectorType>(Ty); }))
+        return InstructionCost::getInvalid();
+
       // Assume that we need to scalarize this intrinsic.
       InstructionCost ScalarizationCost = ScalarizationCostPassed;
       unsigned ScalarCalls = 1;
@@ -1802,6 +1804,11 @@
     // this will emit a costly libcall, adding call overhead and spills. Make it
     // very expensive.
     if (auto *RetVTy = dyn_cast<VectorType>(RetTy)) {
+      // Scalable vectors cannot be scalarized, so return Invalid.
+      if (isa<ScalableVectorType>(RetTy) ||
+          any_of(Tys, [](const Type *Ty) { return isa<ScalableVectorType>(Ty); }))
+        return InstructionCost::getInvalid();
+
       unsigned ScalarizationCost = SkipScalarizationCost ?
         ScalarizationCostPassed : getScalarizationOverhead(RetVTy, true, false);
 


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