[SandboxVec][BottomUpVec] Add -sbvec-stop-bndl flag for debugging #129132
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This patch adds a helper flag for bisection debugging. This flag force-stops vectorization after this many bundles have been considered for vectorization. Using -sbvec-stop-bndl=0 will not vectorize the code at all.
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@llvm/pr-subscribers-vectorizers @llvm/pr-subscribers-llvm-transforms Author: vporpo (vporpo) ChangesThis patch adds a helper flag for bisection debugging. This flag force-stops vectorization after this many bundles have been considered for vectorization. Full diff: https://github.com/llvm/llvm-project/pull/129132.diff 4 Files Affected:
diff --git a/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Legality.h b/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Legality.h
index bc2942f87adcf..4ea840c099e70 100644
--- a/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Legality.h
+++ b/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Legality.h
@@ -98,6 +98,7 @@ enum class ResultReason {
CantSchedule,
Unimplemented,
Infeasible,
+ ForcePackForDebugging,
};
#ifndef NDEBUG
@@ -142,6 +143,8 @@ struct ToStr {
return "Unimplemented";
case ResultReason::Infeasible:
return "Infeasible";
+ case ResultReason::ForcePackForDebugging:
+ return "ForcePackForDebugging";
}
llvm_unreachable("Unknown ResultReason enum");
}
@@ -347,6 +350,10 @@ class LegalityAnalysis {
// TODO: Try to remove the SkipScheduling argument by refactoring the tests.
const LegalityResult &canVectorize(ArrayRef<Value *> Bndl,
bool SkipScheduling = false);
+ /// \Returns a Pack with reason 'ForcePackForDebugging'.
+ const LegalityResult &getForcedPackForDebugging() {
+ return createLegalityResult<Pack>(ResultReason::ForcePackForDebugging);
+ }
void clear();
};
diff --git a/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.h b/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.h
index 2359d54213ef6..af0e07de4f51f 100644
--- a/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.h
+++ b/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.h
@@ -81,6 +81,10 @@ class BottomUpVec final : public RegionPass {
#endif // NDEBUG
};
ActionsVector Actions;
+ /// Helper counter for debugging. It counts the bundles that we attempt to
+ /// vectorize in vectorizeRec().
+ unsigned DebugBndlCnt = 0;
+
/// Recursively try to vectorize \p Bndl and its operands. This populates the
/// `Actions` vector.
Action *vectorizeRec(ArrayRef<Value *> Bndl, ArrayRef<Value *> UserBndl,
diff --git a/llvm/lib/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.cpp b/llvm/lib/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.cpp
index 16eff012c187a..726240f708f6a 100644
--- a/llvm/lib/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.cpp
+++ b/llvm/lib/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.cpp
@@ -32,6 +32,12 @@ static cl::opt<unsigned long>
cl::desc("Vectorize if the invocation count is < than this. 0 "
"disables vectorization."));
+static constexpr const unsigned long StopBundleDisabled =
+ std::numeric_limits<unsigned long>::max();
+static cl::opt<unsigned long>
+ StopBundle("sbvec-stop-bndl", cl::init(StopBundleDisabled), cl::Hidden,
+ cl::desc("Vectorize up to this many bundles."));
+
namespace sandboxir {
static SmallVector<Value *, 4> getOperand(ArrayRef<Value *> Bndl,
@@ -270,7 +276,10 @@ void BottomUpVec::collectPotentiallyDeadInstrs(ArrayRef<Value *> Bndl) {
Action *BottomUpVec::vectorizeRec(ArrayRef<Value *> Bndl,
ArrayRef<Value *> UserBndl, unsigned Depth) {
- const auto &LegalityRes = Legality->canVectorize(Bndl);
+ bool StopForDebug =
+ DebugBndlCnt++ >= StopBundle && StopBundle != StopBundleDisabled;
+ const auto &LegalityRes = StopForDebug ? Legality->getForcedPackForDebugging()
+ : Legality->canVectorize(Bndl);
auto ActionPtr =
std::make_unique<Action>(&LegalityRes, Bndl, UserBndl, Depth);
SmallVector<Action *> Operands;
@@ -469,6 +478,7 @@ bool BottomUpVec::tryVectorize(ArrayRef<Value *> Bndl) {
DeadInstrCandidates.clear();
Legality->clear();
Actions.clear();
+ DebugBndlCnt = 0;
vectorizeRec(Bndl, {}, /*Depth=*/0);
emitVectors();
tryEraseDeadInstrs();
diff --git a/llvm/test/Transforms/SandboxVectorizer/stop_bndl.ll b/llvm/test/Transforms/SandboxVectorizer/stop_bndl.ll
new file mode 100644
index 0000000000000..61e2d82a3e5c1
--- /dev/null
+++ b/llvm/test/Transforms/SandboxVectorizer/stop_bndl.ll
@@ -0,0 +1,71 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=sandbox-vectorizer -sbvec-vec-reg-bits=1024 -sbvec-allow-non-pow2 -sbvec-passes="seed-collection<tr-save,bottom-up-vec,tr-accept>" -sbvec-stop-bndl=0 %s -S | FileCheck %s --check-prefix=STOP0
+; RUN: opt -passes=sandbox-vectorizer -sbvec-vec-reg-bits=1024 -sbvec-allow-non-pow2 -sbvec-passes="seed-collection<tr-save,bottom-up-vec,tr-accept>" -sbvec-stop-bndl=1 %s -S | FileCheck %s --check-prefix=STOP1
+; RUN: opt -passes=sandbox-vectorizer -sbvec-vec-reg-bits=1024 -sbvec-allow-non-pow2 -sbvec-passes="seed-collection<tr-save,bottom-up-vec,tr-accept>" -sbvec-stop-bndl=2 %s -S | FileCheck %s --check-prefix=STOP2
+; RUN: opt -passes=sandbox-vectorizer -sbvec-vec-reg-bits=1024 -sbvec-allow-non-pow2 -sbvec-passes="seed-collection<tr-save,bottom-up-vec,tr-accept>" -sbvec-stop-bndl=3 %s -S | FileCheck %s --check-prefix=STOP3
+; RUN: opt -passes=sandbox-vectorizer -sbvec-vec-reg-bits=1024 -sbvec-allow-non-pow2 -sbvec-passes="seed-collection<tr-save,bottom-up-vec,tr-accept>" %s -S | FileCheck %s --check-prefix=NOSTOP
+
+define void @stop_bndl(ptr %ptr) {
+; STOP0-LABEL: define void @stop_bndl(
+; STOP0-SAME: ptr [[PTR:%.*]]) {
+; STOP0-NEXT: [[PTR0:%.*]] = getelementptr float, ptr [[PTR]], i32 0
+; STOP0-NEXT: [[PTR1:%.*]] = getelementptr float, ptr [[PTR]], i32 1
+; STOP0-NEXT: [[LD0:%.*]] = load float, ptr [[PTR0]], align 4
+; STOP0-NEXT: [[LD1:%.*]] = load float, ptr [[PTR1]], align 4
+; STOP0-NEXT: [[ADD0:%.*]] = fadd float [[LD0]], 0.000000e+00
+; STOP0-NEXT: [[ADD1:%.*]] = fadd float [[LD1]], 0.000000e+00
+; STOP0-NEXT: store float [[ADD0]], ptr [[PTR0]], align 4
+; STOP0-NEXT: store float [[ADD1]], ptr [[PTR1]], align 4
+; STOP0-NEXT: ret void
+;
+; STOP1-LABEL: define void @stop_bndl(
+; STOP1-SAME: ptr [[PTR:%.*]]) {
+; STOP1-NEXT: [[PTR0:%.*]] = getelementptr float, ptr [[PTR]], i32 0
+; STOP1-NEXT: [[PTR1:%.*]] = getelementptr float, ptr [[PTR]], i32 1
+; STOP1-NEXT: [[LD0:%.*]] = load float, ptr [[PTR0]], align 4
+; STOP1-NEXT: [[LD1:%.*]] = load float, ptr [[PTR1]], align 4
+; STOP1-NEXT: [[ADD0:%.*]] = fadd float [[LD0]], 0.000000e+00
+; STOP1-NEXT: [[ADD1:%.*]] = fadd float [[LD1]], 0.000000e+00
+; STOP1-NEXT: [[PACK:%.*]] = insertelement <2 x float> poison, float [[ADD0]], i32 0
+; STOP1-NEXT: [[PACK1:%.*]] = insertelement <2 x float> [[PACK]], float [[ADD1]], i32 1
+; STOP1-NEXT: store <2 x float> [[PACK1]], ptr [[PTR0]], align 4
+; STOP1-NEXT: ret void
+;
+; STOP2-LABEL: define void @stop_bndl(
+; STOP2-SAME: ptr [[PTR:%.*]]) {
+; STOP2-NEXT: [[PTR0:%.*]] = getelementptr float, ptr [[PTR]], i32 0
+; STOP2-NEXT: [[PTR1:%.*]] = getelementptr float, ptr [[PTR]], i32 1
+; STOP2-NEXT: [[LD0:%.*]] = load float, ptr [[PTR0]], align 4
+; STOP2-NEXT: [[LD1:%.*]] = load float, ptr [[PTR1]], align 4
+; STOP2-NEXT: [[PACK:%.*]] = insertelement <2 x float> poison, float [[LD0]], i32 0
+; STOP2-NEXT: [[PACK1:%.*]] = insertelement <2 x float> [[PACK]], float [[LD1]], i32 1
+; STOP2-NEXT: [[VEC:%.*]] = fadd <2 x float> [[PACK1]], zeroinitializer
+; STOP2-NEXT: store <2 x float> [[VEC]], ptr [[PTR0]], align 4
+; STOP2-NEXT: ret void
+;
+; STOP3-LABEL: define void @stop_bndl(
+; STOP3-SAME: ptr [[PTR:%.*]]) {
+; STOP3-NEXT: [[PTR0:%.*]] = getelementptr float, ptr [[PTR]], i32 0
+; STOP3-NEXT: [[VECL:%.*]] = load <2 x float>, ptr [[PTR0]], align 4
+; STOP3-NEXT: [[VEC:%.*]] = fadd <2 x float> [[VECL]], zeroinitializer
+; STOP3-NEXT: store <2 x float> [[VEC]], ptr [[PTR0]], align 4
+; STOP3-NEXT: ret void
+;
+; NOSTOP-LABEL: define void @stop_bndl(
+; NOSTOP-SAME: ptr [[PTR:%.*]]) {
+; NOSTOP-NEXT: [[PTR0:%.*]] = getelementptr float, ptr [[PTR]], i32 0
+; NOSTOP-NEXT: [[VECL:%.*]] = load <2 x float>, ptr [[PTR0]], align 4
+; NOSTOP-NEXT: [[VEC:%.*]] = fadd <2 x float> [[VECL]], zeroinitializer
+; NOSTOP-NEXT: store <2 x float> [[VEC]], ptr [[PTR0]], align 4
+; NOSTOP-NEXT: ret void
+;
+ %ptr0 = getelementptr float, ptr %ptr, i32 0
+ %ptr1 = getelementptr float, ptr %ptr, i32 1
+ %ld0 = load float, ptr %ptr0
+ %ld1 = load float, ptr %ptr1
+ %add0 = fadd float %ld0, 0.0
+ %add1 = fadd float %ld1, 0.0
+ store float %add0, ptr %ptr0
+ store float %add1, ptr %ptr1
+ ret void
+}
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tmsri
approved these changes
Feb 28, 2025
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This patch adds a helper flag for bisection debugging. This flag force-stops vectorization after this many bundles have been considered for vectorization.
Using -sbvec-stop-bndl=0 will not vectorize the code at all.