[llvm] [LoopUnroll] Consider simplified operands while retrieving TTI instruction cost (PR #70929)
Sergey Kachkov via llvm-commits
llvm-commits at lists.llvm.org
Fri Dec 1 01:31:33 PST 2023
https://github.com/skachkov-sc updated https://github.com/llvm/llvm-project/pull/70929
>From 1b6cdeffa9c863f3224dc1ef1ff561a94ad20a28 Mon Sep 17 00:00:00 2001
From: Sergey Kachkov <sergey.kachkov at syntacore.com>
Date: Mon, 30 Oct 2023 12:28:14 +0300
Subject: [PATCH 1/3] [LoopUnroll][NFC] Add pre-commit test
---
.../Transforms/LoopUnroll/RISCV/unroll-Os.ll | 35 +++++++++++++++++++
1 file changed, 35 insertions(+)
create mode 100644 llvm/test/Transforms/LoopUnroll/RISCV/unroll-Os.ll
diff --git a/llvm/test/Transforms/LoopUnroll/RISCV/unroll-Os.ll b/llvm/test/Transforms/LoopUnroll/RISCV/unroll-Os.ll
new file mode 100644
index 000000000000000..d94cba659051f17
--- /dev/null
+++ b/llvm/test/Transforms/LoopUnroll/RISCV/unroll-Os.ll
@@ -0,0 +1,35 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
+; RUN: opt < %s -S -mtriple=riscv64 -passes=loop-unroll | FileCheck %s
+
+; Function Attrs: optsize
+define void @foo(ptr %array, i32 %x) #0 {
+; CHECK-LABEL: define void @foo
+; CHECK-SAME: (ptr [[ARRAY:%.*]], i32 [[X:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[FOR_BODY:%.*]]
+; CHECK: for.body:
+; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INDVARS_IV_NEXT:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[ARRAY]], i64 [[INDVARS_IV]]
+; CHECK-NEXT: store i32 [[X]], ptr [[ARRAYIDX]], align 4
+; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
+; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INDVARS_IV_NEXT]], 4
+; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[FOR_COND_CLEANUP:%.*]], label [[FOR_BODY]]
+; CHECK: for.cond.cleanup:
+; CHECK-NEXT: ret void
+;
+entry:
+ br label %for.body
+
+for.body:
+ %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+ %arrayidx = getelementptr inbounds i32, ptr %array, i64 %indvars.iv
+ store i32 %x, ptr %arrayidx, align 4
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+ %exitcond.not = icmp eq i64 %indvars.iv.next, 4
+ br i1 %exitcond.not, label %for.cond.cleanup, label %for.body
+
+for.cond.cleanup:
+ ret void
+}
+
+attributes #0 = { optsize }
>From f89182079d9640ba1a87b37461d2a79cabe2ff1d Mon Sep 17 00:00:00 2001
From: Sergey Kachkov <sergey.kachkov at syntacore.com>
Date: Fri, 27 Oct 2023 19:35:20 +0300
Subject: [PATCH 2/3] [LoopUnroll] Consider simplified operands while
retrieving TTI instruction cost
Get more precise cost of instruction after LoopUnroll considering that
some operands of it can be simplified, e.g. induction variable will be
replaced by constant after full unrolling.
---
llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp | 10 +++++++++-
llvm/test/Transforms/LoopUnroll/RISCV/unroll-Os.ll | 14 +++++++-------
2 files changed, 16 insertions(+), 8 deletions(-)
diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
index 446aa497026d3fb..470bc3038669d83 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -443,7 +443,15 @@ static std::optional<EstimatedUnrollCost> analyzeLoopUnrollCost(
// First accumulate the cost of this instruction.
if (!Cost.IsFree) {
- UnrolledCost += TTI.getInstructionCost(I, CostKind);
+ // Consider simplified operands in instruction cost.
+ SmallVector<Value *, 4> Operands;
+ transform(I->operands(), std::back_inserter(Operands),
+ [&](Value *Op) {
+ if (auto Res = SimplifiedValues.lookup(Op))
+ return Res;
+ return Op;
+ });
+ UnrolledCost += TTI.getInstructionCost(I, Operands, CostKind);
LLVM_DEBUG(dbgs() << "Adding cost of instruction (iteration "
<< Iteration << "): ");
LLVM_DEBUG(I->dump());
diff --git a/llvm/test/Transforms/LoopUnroll/RISCV/unroll-Os.ll b/llvm/test/Transforms/LoopUnroll/RISCV/unroll-Os.ll
index d94cba659051f17..26de40bf1dc13e4 100644
--- a/llvm/test/Transforms/LoopUnroll/RISCV/unroll-Os.ll
+++ b/llvm/test/Transforms/LoopUnroll/RISCV/unroll-Os.ll
@@ -8,13 +8,13 @@ define void @foo(ptr %array, i32 %x) #0 {
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
-; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INDVARS_IV_NEXT:%.*]], [[FOR_BODY]] ]
-; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[ARRAY]], i64 [[INDVARS_IV]]
-; CHECK-NEXT: store i32 [[X]], ptr [[ARRAYIDX]], align 4
-; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
-; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INDVARS_IV_NEXT]], 4
-; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[FOR_COND_CLEANUP:%.*]], label [[FOR_BODY]]
-; CHECK: for.cond.cleanup:
+; CHECK-NEXT: store i32 [[X]], ptr [[ARRAY]], align 4
+; CHECK-NEXT: [[ARRAYIDX_1:%.*]] = getelementptr inbounds i32, ptr [[ARRAY]], i64 1
+; CHECK-NEXT: store i32 [[X]], ptr [[ARRAYIDX_1]], align 4
+; CHECK-NEXT: [[ARRAYIDX_2:%.*]] = getelementptr inbounds i32, ptr [[ARRAY]], i64 2
+; CHECK-NEXT: store i32 [[X]], ptr [[ARRAYIDX_2]], align 4
+; CHECK-NEXT: [[ARRAYIDX_3:%.*]] = getelementptr inbounds i32, ptr [[ARRAY]], i64 3
+; CHECK-NEXT: store i32 [[X]], ptr [[ARRAYIDX_3]], align 4
; CHECK-NEXT: ret void
;
entry:
>From 45e8d46554554e5ef334f1ed2ea2454a774cb661 Mon Sep 17 00:00:00 2001
From: Sergey Kachkov <sergey.kachkov at syntacore.com>
Date: Fri, 1 Dec 2023 12:30:23 +0300
Subject: [PATCH 3/3] Fix AMDGPU test
---
.../AMDGPU/unroll-cost-addrspacecast.ll | 22 +++++++++++++------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/llvm/test/Transforms/LoopUnroll/AMDGPU/unroll-cost-addrspacecast.ll b/llvm/test/Transforms/LoopUnroll/AMDGPU/unroll-cost-addrspacecast.ll
index 6ec64bfba895961..d189f9170485222 100644
--- a/llvm/test/Transforms/LoopUnroll/AMDGPU/unroll-cost-addrspacecast.ll
+++ b/llvm/test/Transforms/LoopUnroll/AMDGPU/unroll-cost-addrspacecast.ll
@@ -1,4 +1,6 @@
-; RUN: opt -S -mtriple=amdgcn-unknown-amdhsa -mcpu=hawaii -passes=loop-unroll -unroll-threshold=49 -unroll-peel-count=0 -unroll-allow-partial=false -unroll-max-iteration-count-to-analyze=16 < %s | FileCheck %s
+; RUN: opt -S -mtriple=amdgcn-unknown-amdhsa -mcpu=hawaii -passes=loop-unroll -unroll-threshold=57 -unroll-peel-count=0 -unroll-allow-partial=false -unroll-max-iteration-count-to-analyze=16 < %s | FileCheck %s
+
+ at indices = external global [16 x i32]
; CHECK-LABEL: @test_func_addrspacecast_cost_noop(
; CHECK-NOT: br i1
@@ -9,8 +11,10 @@ entry:
for.body:
%indvars.iv = phi i32 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
%sum.02 = phi float [ %fmul, %for.body ], [ 0.0, %entry ]
- %arrayidx.in = getelementptr inbounds float, ptr addrspace(1) %in, i32 %indvars.iv
- %arrayidx.out = getelementptr inbounds float, ptr addrspace(1) %out, i32 %indvars.iv
+ %idx.ptr = getelementptr inbounds [16 x i32], ptr @indices, i32 0, i32 %indvars.iv
+ %index = load i32, ptr %idx.ptr
+ %arrayidx.in = getelementptr inbounds float, ptr addrspace(1) %in, i32 %index
+ %arrayidx.out = getelementptr inbounds float, ptr addrspace(1) %out, i32 %index
%cast.in = addrspacecast ptr addrspace(1) %arrayidx.in to ptr
%cast.out = addrspacecast ptr addrspace(1) %arrayidx.out to ptr
%load = load float, ptr %cast.in
@@ -34,8 +38,10 @@ entry:
for.body:
%indvars.iv = phi i32 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
%sum.02 = phi float [ %fmul, %for.body ], [ 0.0, %entry ]
- %arrayidx.in = getelementptr inbounds float, ptr %in, i32 %indvars.iv
- %arrayidx.out = getelementptr inbounds float, ptr %out, i32 %indvars.iv
+ %idx.ptr = getelementptr inbounds [16 x i32], ptr @indices, i32 0, i32 %indvars.iv
+ %index = load i32, ptr %idx.ptr
+ %arrayidx.in = getelementptr inbounds float, ptr %in, i32 %index
+ %arrayidx.out = getelementptr inbounds float, ptr %out, i32 %index
%cast.in = addrspacecast ptr %arrayidx.in to ptr addrspace(3)
%cast.out = addrspacecast ptr %arrayidx.out to ptr addrspace(3)
%load = load float, ptr addrspace(3) %cast.in
@@ -58,8 +64,10 @@ entry:
for.body:
%indvars.iv = phi i32 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
%sum.02 = phi float [ %fmul, %for.body ], [ 0.0, %entry ]
- %arrayidx.in = getelementptr inbounds float, ptr addrspace(3) %in, i32 %indvars.iv
- %arrayidx.out = getelementptr inbounds float, ptr addrspace(3) %out, i32 %indvars.iv
+ %idx.ptr = getelementptr inbounds [16 x i32], ptr @indices, i32 0, i32 %indvars.iv
+ %index = load i32, ptr %idx.ptr
+ %arrayidx.in = getelementptr inbounds float, ptr addrspace(3) %in, i32 %index
+ %arrayidx.out = getelementptr inbounds float, ptr addrspace(3) %out, i32 %index
%cast.in = addrspacecast ptr addrspace(3) %arrayidx.in to ptr
%cast.out = addrspacecast ptr addrspace(3) %arrayidx.out to ptr
%load = load float, ptr %cast.in
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