CostModel/RISCV: tweak cost of vector ctpop under ZVBB

[artagnon]

Under RISCV experimental-zvbb, vector variants of llvm.ctpop lower to a single instruction: vcpop. The cost-model does not check for the ZVBB extension, and always associates a high cost to vector variants of llvm.ctpop. Fix this defect.

[llvmbot]

@llvm/pr-subscribers-backend-risc-v

@llvm/pr-subscribers-llvm-analysis

Changes

Under RISCV experimental-zvbb, vector variants of llvm.ctpop lower to a single instruction: vcpop. The cost-model does not check for the ZVBB extension, and always associates a high cost to vector variants of llvm.ctpop. Fix this defect.

-- 8< --
Based on #67013. Please review only the second patch.

---

Full diff: https://github.com/llvm/llvm-project/pull/67020.diff

2 Files Affected:

• (modified) llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp (+6)
• (added) llvm/test/Analysis/CostModel/RISCV/ctpop.ll (+95)

diff --git a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
index 6b950cd8a49fc09..2dbc3663046304e 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
@@ -1074,6 +1074,12 @@ RISCVTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
       return LT.first;
     break;
   }
+  case Intrinsic::ctpop: {
+    auto LT = getTypeLegalizationCost(RetTy);
+    if (ST->hasVInstructions() && ST->hasStdExtZvbb() && LT.second.isVector())
+      return LT.first;
+    break;
+  }
   case Intrinsic::abs: {
     auto LT = getTypeLegalizationCost(RetTy);
     if (ST->hasVInstructions() && LT.second.isVector()) {
diff --git a/llvm/test/Analysis/CostModel/RISCV/ctpop.ll b/llvm/test/Analysis/CostModel/RISCV/ctpop.ll
new file mode 100644
index 000000000000000..dc07df9a3b40f02
--- /dev/null
+++ b/llvm/test/Analysis/CostModel/RISCV/ctpop.ll
@@ -0,0 +1,95 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
+; RUN: opt < %s -passes="print<cost-model>" 2>&1 -disable-output -S -mtriple=riscv64 -mattr=+v,+experimental-zvbb -riscv-v-vector-bits-min=-1 | FileCheck %s --check-prefix=ZVBB
+; Vector ctpop only exists under zvbb
+; RUN: opt < %s -passes="print<cost-model>" 2>&1 -disable-output -S -mtriple=riscv64 -mattr=+v -riscv-v-vector-bits-min=-1 | FileCheck %s --check-prefix=NOZVBB
+
+define void @ctpop() {
+; ZVBB-LABEL: 'ctpop'
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %1 = call i8 @llvm.ctpop.i8(i8 undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %2 = call <2 x i8> @llvm.ctpop.v2i8(<2 x i8> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %3 = call <4 x i8> @llvm.ctpop.v4i8(<4 x i8> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %4 = call <8 x i8> @llvm.ctpop.v8i8(<8 x i8> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %5 = call <16 x i8> @llvm.ctpop.v16i8(<16 x i8> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %6 = call i16 @llvm.ctpop.i16(i16 undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %7 = call <2 x i16> @llvm.ctpop.v2i16(<2 x i16> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %8 = call <4 x i16> @llvm.ctpop.v4i16(<4 x i16> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %9 = call <8 x i16> @llvm.ctpop.v8i16(<8 x i16> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %10 = call <16 x i16> @llvm.ctpop.v16i16(<16 x i16> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %11 = call i32 @llvm.ctpop.i32(i32 undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %12 = call <2 x i32> @llvm.ctpop.v2i32(<2 x i32> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %13 = call <4 x i32> @llvm.ctpop.v4i32(<4 x i32> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %14 = call <8 x i32> @llvm.ctpop.v8i32(<8 x i32> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %15 = call <16 x i32> @llvm.ctpop.v16i32(<16 x i32> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %16 = call i64 @llvm.ctpop.i64(i64 undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %17 = call <2 x i64> @llvm.ctpop.v2i64(<2 x i64> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %18 = call <4 x i64> @llvm.ctpop.v4i64(<4 x i64> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %19 = call <8 x i64> @llvm.ctpop.v8i64(<8 x i64> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %20 = call <16 x i64> @llvm.ctpop.v16i64(<16 x i64> undef)
+; ZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret void
+;
+; NOZVBB-LABEL: 'ctpop'
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %1 = call i8 @llvm.ctpop.i8(i8 undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %2 = call <2 x i8> @llvm.ctpop.v2i8(<2 x i8> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %3 = call <4 x i8> @llvm.ctpop.v4i8(<4 x i8> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %4 = call <8 x i8> @llvm.ctpop.v8i8(<8 x i8> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %5 = call <16 x i8> @llvm.ctpop.v16i8(<16 x i8> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %6 = call i16 @llvm.ctpop.i16(i16 undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 19 for instruction: %7 = call <2 x i16> @llvm.ctpop.v2i16(<2 x i16> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 19 for instruction: %8 = call <4 x i16> @llvm.ctpop.v4i16(<4 x i16> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 19 for instruction: %9 = call <8 x i16> @llvm.ctpop.v8i16(<8 x i16> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 19 for instruction: %10 = call <16 x i16> @llvm.ctpop.v16i16(<16 x i16> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %11 = call i32 @llvm.ctpop.i32(i32 undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 20 for instruction: %12 = call <2 x i32> @llvm.ctpop.v2i32(<2 x i32> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 20 for instruction: %13 = call <4 x i32> @llvm.ctpop.v4i32(<4 x i32> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 20 for instruction: %14 = call <8 x i32> @llvm.ctpop.v8i32(<8 x i32> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 20 for instruction: %15 = call <16 x i32> @llvm.ctpop.v16i32(<16 x i32> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %16 = call i64 @llvm.ctpop.i64(i64 undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 21 for instruction: %17 = call <2 x i64> @llvm.ctpop.v2i64(<2 x i64> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 21 for instruction: %18 = call <4 x i64> @llvm.ctpop.v4i64(<4 x i64> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 21 for instruction: %19 = call <8 x i64> @llvm.ctpop.v8i64(<8 x i64> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 21 for instruction: %20 = call <16 x i64> @llvm.ctpop.v16i64(<16 x i64> undef)
+; NOZVBB-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret void
+;
+  call i8 @llvm.ctpop.i8(i8 undef)
+  call <2 x i8> @llvm.ctpop.v2i8(<2 x i8> undef)
+  call <4 x i8> @llvm.ctpop.v4i8(<4 x i8> undef)
+  call <8 x i8> @llvm.ctpop.v8i8(<8 x i8> undef)
+  call <16 x i8> @llvm.ctpop.v16i8(<16 x i8> undef)
+  call i16 @llvm.ctpop.i16(i16 undef)
+  call <2 x i16> @llvm.ctpop.v2i16(<2 x i16> undef)
+  call <4 x i16> @llvm.ctpop.v4i16(<4 x i16> undef)
+  call <8 x i16> @llvm.ctpop.v8i16(<8 x i16> undef)
+  call <16 x i16> @llvm.ctpop.v16i16(<16 x i16> undef)
+  call i32 @llvm.ctpop.i32(i32 undef)
+  call <2 x i32> @llvm.ctpop.v2i32(<2 x i32> undef)
+  call <4 x i32> @llvm.ctpop.v4i32(<4 x i32> undef)
+  call <8 x i32> @llvm.ctpop.v8i32(<8 x i32> undef)
+  call <16 x i32> @llvm.ctpop.v16i32(<16 x i32> undef)
+  call i64 @llvm.ctpop.i64(i64 undef)
+  call <2 x i64> @llvm.ctpop.v2i64(<2 x i64> undef)
+  call <4 x i64> @llvm.ctpop.v4i64(<4 x i64> undef)
+  call <8 x i64> @llvm.ctpop.v8i64(<8 x i64> undef)
+  call <16 x i64> @llvm.ctpop.v16i64(<16 x i64> undef)
+  ret void
+}
+
+declare i8 @llvm.ctpop.i8(i8)
+declare <2 x i8> @llvm.ctpop.v2i8(<2 x i8>)
+declare <4 x i8> @llvm.ctpop.v4i8(<4 x i8>)
+declare <8 x i8> @llvm.ctpop.v8i8(<8 x i8>)
+declare <16 x i8> @llvm.ctpop.v16i8(<16 x i8>)
+declare i16 @llvm.ctpop.i16(i16)
+declare <2 x i16> @llvm.ctpop.v2i16(<2 x i16>)
+declare <4 x i16> @llvm.ctpop.v4i16(<4 x i16>)
+declare <8 x i16> @llvm.ctpop.v8i16(<8 x i16>)
+declare <16 x i16> @llvm.ctpop.v16i16(<16 x i16>)
+declare i32 @llvm.ctpop.i32(i32)
+declare <2 x i32> @llvm.ctpop.v2i32(<2 x i32>)
+declare <4 x i32> @llvm.ctpop.v4i32(<4 x i32>)
+declare <8 x i32> @llvm.ctpop.v8i32(<8 x i32>)
+declare <16 x i32> @llvm.ctpop.v16i32(<16 x i32>)
+declare i64 @llvm.ctpop.i64(i64)
+declare <2 x i64> @llvm.ctpop.v2i64(<2 x i64>)
+declare <4 x i64> @llvm.ctpop.v4i64(<4 x i64>)
+declare <8 x i64> @llvm.ctpop.v8i64(<8 x i64>)
+declare <16 x i64> @llvm.ctpop.v16i64(<16 x i64>)

[preames]

Code change LGTM once rebased over revised test. (See other review)

[artagnon]

@preames Fixed, thanks.