https://github.com/hassnaaHamdi created
https://github.com/llvm/llvm-project/pull/127101
As exposed by #125094, we are missing cost computation for some binary
VPInstructions we created based on original IR instructions. Their cost should
be considered.
PR: #125434
Author: Florian Hahn <f...@fhahn.com>
>From e5a66bd3e14774c14a024ef0f8de3d5a2a07d464 Mon Sep 17 00:00:00 2001
From: Hassnaa Hamdi <hassnaa.ha...@arm.com>
Date: Thu, 13 Feb 2025 17:48:02 +0000
Subject: [PATCH] [VPlan] Compute cost for binary op VPInstruction with
underlying values. #125434
As exposed by #125094, we are missing cost computation for some
binary VPInstructions we created based on original IR instructions.
Their cost should be considered.
PR: #125434
Author: Florian Hahn <f...@fhahn.com>
Change-Id: Icf985b3f1cd40898a17faaf47b241e2651f9e8dd
---
llvm/lib/Transforms/Vectorize/VPlan.h | 5 +-
.../lib/Transforms/Vectorize/VPlanRecipes.cpp | 24 ++++++
.../X86/CostModel/vpinstruction-cost.ll | 74 +++++++++++++++++++
3 files changed, 99 insertions(+), 4 deletions(-)
create mode 100644
llvm/test/Transforms/LoopVectorize/X86/CostModel/vpinstruction-cost.ll
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h
b/llvm/lib/Transforms/Vectorize/VPlan.h
index 6c95b08a02014..f4e5b1870894c 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -1314,10 +1314,7 @@ class VPInstruction : public VPRecipeWithIRFlags,
/// Return the cost of this VPInstruction.
InstructionCost computeCost(ElementCount VF,
- VPCostContext &Ctx) const override {
- // TODO: Compute accurate cost after retiring the legacy cost model.
- return 0;
- }
+ VPCostContext &Ctx) const override;
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
/// Print the VPInstruction to \p O.
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 6b746a48c46ec..97be2da24fc37 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -703,6 +703,30 @@ Value *VPInstruction::generate(VPTransformState &State) {
}
}
+InstructionCost VPInstruction::computeCost(ElementCount VF,
+ VPCostContext &Ctx) const {
+ if (Instruction::isBinaryOp(getOpcode())) {
+ if (!getUnderlyingValue()) {
+ // TODO: Compute cost for VPInstructions without underlying values once
+ // the legacy cost model has been retired.
+ return 0;
+ }
+ assert(!doesGeneratePerAllLanes() &&
+ "Should only generate a vector value or single scalar, not scalars "
+ "for all lanes.");
+ Type *ResTy = Ctx.Types.inferScalarType(this);
+ if (!vputils::onlyFirstLaneUsed(this))
+ ResTy = toVectorTy(ResTy, VF);
+ return Ctx.TTI.getArithmeticInstrCost(getOpcode(), ResTy, Ctx.CostKind);
+ }
+
+ // TODO: Compute cost other VPInstructions once the legacy cost model has
+ // been retired.
+ assert(!getUnderlyingValue() &&
+ "unexpected VPInstruction witht underlying value");
+ return 0;
+}
+
bool VPInstruction::isVectorToScalar() const {
return getOpcode() == VPInstruction::ExtractFromEnd ||
getOpcode() == VPInstruction::ComputeReductionResult ||
diff --git
a/llvm/test/Transforms/LoopVectorize/X86/CostModel/vpinstruction-cost.ll
b/llvm/test/Transforms/LoopVectorize/X86/CostModel/vpinstruction-cost.ll
new file mode 100644
index 0000000000000..e7229bd0e7521
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/X86/CostModel/vpinstruction-cost.ll
@@ -0,0 +1,74 @@
+; NOTE: Assertions have been autogenerated by
utils/update_analyze_test_checks.py UTC_ARGS: --filter "Cost of"
+; RUN: opt -S -passes=loop-vectorize -mcpu=skylake-avx512
-mtriple=x86_64-apple-macosx -debug -disable-output -S %s 2>&1 | FileCheck %s
+
+; REQUIRES: asserts
+
+target datalayout =
"e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+
+define void @wide_or_replaced_with_add_vpinstruction(ptr %src, ptr noalias
%dst) {
+; CHECK-LABEL: 'wide_or_replaced_with_add_vpinstruction'
+; CHECK: Cost of 1 for VF 2: induction instruction %iv.next = add nuw nsw i64
%iv, 1
+; CHECK: Cost of 0 for VF 2: induction instruction %iv = phi i64 [ 0, %entry
], [ %iv.next, %loop.latch ]
+; CHECK: Cost of 1 for VF 2: exit condition instruction %exitcond = icmp eq
i64 %iv.next, 32
+; CHECK: Cost of 0 for VF 2: EMIT vp<%3> = CANONICAL-INDUCTION ir<0>,
vp<%index.next>
+; CHECK: Cost of 0 for VF 2: ir<%iv> = WIDEN-INDUCTION ir<0>, ir<1>, vp<%0>
+; CHECK: Cost of 0 for VF 2: vp<%4> = SCALAR-STEPS vp<%3>, ir<1>
+; CHECK: Cost of 0 for VF 2: CLONE ir<%g.src> = getelementptr inbounds
ir<%src>, vp<%4>
+; CHECK: Cost of 0 for VF 2: vp<%5> = vector-pointer ir<%g.src>
+; CHECK: Cost of 1 for VF 2: WIDEN ir<%l> = load vp<%5>
+; CHECK: Cost of 1 for VF 2: WIDEN ir<%iv.4> = add ir<%iv>, ir<4>
+; CHECK: Cost of 1 for VF 2: WIDEN ir<%c> = icmp ule ir<%l>, ir<128>
+; CHECK: Cost of 1 for VF 2: EMIT ir<%or> = add ir<%iv.4>, ir<1>
+; CHECK: Cost of 0 for VF 2: CLONE ir<%g.dst> = getelementptr ir<%dst>,
ir<%or>
+; CHECK: Cost of 0 for VF 2: vp<%6> = vector-pointer ir<%g.dst>
+; CHECK: Cost of 1 for VF 2: WIDEN store vp<%6>, ir<%iv.4>, ir<%c>
+; CHECK: Cost of 0 for VF 2: EMIT vp<%index.next> = add nuw vp<%3>, vp<%1>
+; CHECK: Cost of 0 for VF 2: EMIT branch-on-count vp<%index.next>, vp<%2>
+; CHECK: Cost of 0 for VF 2: vector loop backedge
+; CHECK: Cost of 1 for VF 4: induction instruction %iv.next = add nuw nsw i64
%iv, 1
+; CHECK: Cost of 0 for VF 4: induction instruction %iv = phi i64 [ 0, %entry
], [ %iv.next, %loop.latch ]
+; CHECK: Cost of 1 for VF 4: exit condition instruction %exitcond = icmp eq
i64 %iv.next, 32
+; CHECK: Cost of 0 for VF 4: EMIT vp<%3> = CANONICAL-INDUCTION ir<0>,
vp<%index.next>
+; CHECK: Cost of 0 for VF 4: ir<%iv> = WIDEN-INDUCTION ir<0>, ir<1>, vp<%0>
+; CHECK: Cost of 0 for VF 4: vp<%4> = SCALAR-STEPS vp<%3>, ir<1>
+; CHECK: Cost of 0 for VF 4: CLONE ir<%g.src> = getelementptr inbounds
ir<%src>, vp<%4>
+; CHECK: Cost of 0 for VF 4: vp<%5> = vector-pointer ir<%g.src>
+; CHECK: Cost of 1 for VF 4: WIDEN ir<%l> = load vp<%5>
+; CHECK: Cost of 1 for VF 4: WIDEN ir<%iv.4> = add ir<%iv>, ir<4>
+; CHECK: Cost of 1 for VF 4: WIDEN ir<%c> = icmp ule ir<%l>, ir<128>
+; CHECK: Cost of 1 for VF 4: EMIT ir<%or> = add ir<%iv.4>, ir<1>
+; CHECK: Cost of 0 for VF 4: CLONE ir<%g.dst> = getelementptr ir<%dst>,
ir<%or>
+; CHECK: Cost of 0 for VF 4: vp<%6> = vector-pointer ir<%g.dst>
+; CHECK: Cost of 1 for VF 4: WIDEN store vp<%6>, ir<%iv.4>, ir<%c>
+; CHECK: Cost of 0 for VF 4: EMIT vp<%index.next> = add nuw vp<%3>, vp<%1>
+; CHECK: Cost of 0 for VF 4: EMIT branch-on-count vp<%index.next>, vp<%2>
+; CHECK: Cost of 0 for VF 4: vector loop backedge
+; CHECK: Cost of 1 for VF 4: induction instruction %iv.next = add nuw nsw i64
%iv, 1
+; CHECK: Cost of 0 for VF 4: induction instruction %iv = phi i64 [ 0, %entry
], [ %iv.next, %loop.latch ]
+; CHECK: Cost of 1 for VF 4: exit condition instruction %exitcond = icmp eq
i64 %iv.next, 32
+;
+entry:
+ br label %loop.header
+
+loop.header:
+ %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+ %g.src = getelementptr inbounds i64, ptr %src, i64 %iv
+ %l = load i64, ptr %g.src
+ %iv.4 = add nuw nsw i64 %iv, 4
+ %c = icmp ule i64 %l, 128
+ br i1 %c, label %loop.then, label %loop.latch
+
+loop.then:
+ %or = or disjoint i64 %iv.4, 1
+ %g.dst = getelementptr inbounds i64, ptr %dst, i64 %or
+ store i64 %iv.4, ptr %g.dst, align 4
+ br label %loop.latch
+
+loop.latch:
+ %iv.next = add nuw nsw i64 %iv, 1
+ %exitcond = icmp eq i64 %iv.next, 32
+ br i1 %exitcond, label %exit, label %loop.header
+
+exit:
+ ret void
+}
\ No newline at end of file
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