[llvm] ce3c3cb - [llvm-reduce] Check if reduction fails/is redundant before invoking oracle
Arthur Eubanks via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 18 08:44:07 PDT 2022
Author: Arthur Eubanks
Date: 2022-10-18T08:43:56-07:00
New Revision: ce3c3cb2912425bb4367bfbe9a4c68a6d6f0a04a
URL: https://github.com/llvm/llvm-project/commit/ce3c3cb2912425bb4367bfbe9a4c68a6d6f0a04a
DIFF: https://github.com/llvm/llvm-project/commit/ce3c3cb2912425bb4367bfbe9a4c68a6d6f0a04a.diff
LOG: [llvm-reduce] Check if reduction fails/is redundant before invoking oracle
So we don't over count the number of chunks and do unnecessary work reducing more chunks than exist.
This lowers some random reduction I tested with locally from 250s to 232s.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D136127
Added:
llvm/test/tools/llvm-reduce/oracle-count.ll
Modified:
llvm/tools/llvm-reduce/deltas/ReduceOpcodes.cpp
llvm/tools/llvm-reduce/deltas/ReduceOperands.cpp
llvm/tools/llvm-reduce/deltas/SimplifyInstructions.cpp
Removed:
################################################################################
diff --git a/llvm/test/tools/llvm-reduce/oracle-count.ll b/llvm/test/tools/llvm-reduce/oracle-count.ll
new file mode 100644
index 0000000000000..948c6da262e24
--- /dev/null
+++ b/llvm/test/tools/llvm-reduce/oracle-count.ll
@@ -0,0 +1,23 @@
+; RUN: llvm-reduce --test FileCheck --test-arg --check-prefixes=CHECK-INTERESTINGNESS --test-arg %s --test-arg --input-file %s -o %t 2>&1 | FileCheck %s --check-prefix=CHECK-LOG
+; RUN: FileCheck --check-prefixes=CHECK-FINAL --input-file=%t %s
+
+; CHECK-INTERESTINGNESS: ret i32
+; CHECK-FINAL: ret i32 0
+
+; Test that we don't invoke the oracle more than necessary (e.g. check the
+; oracle then perform some failable/redundant reduction, as opposed to check if
+; a reduction will fail/be redundant before invoking the oracle). This prevents
+; overestimation of the number of possible reductions and the number of times we
+; attempt to reduce.
+
+; IR passes
+; CHECK-LOG: Saved new best reduction
+; Module data
+; CHECK-LOG: Saved new best reduction
+; SimplifyCFG
+; CHECK-LOG: Saved new best reduction
+; CHECK-LOG-NOT: Saved new best reduction
+
+define i32 @f() {
+ ret i32 0
+}
\ No newline at end of file
diff --git a/llvm/tools/llvm-reduce/deltas/ReduceOpcodes.cpp b/llvm/tools/llvm-reduce/deltas/ReduceOpcodes.cpp
index 99beb318ef169..776027d553ebe 100644
--- a/llvm/tools/llvm-reduce/deltas/ReduceOpcodes.cpp
+++ b/llvm/tools/llvm-reduce/deltas/ReduceOpcodes.cpp
@@ -87,12 +87,13 @@ static void replaceOpcodesInModule(Oracle &O, Module &Mod) {
for (Function &F : Mod) {
for (BasicBlock &BB : F)
for (Instruction &I : make_early_inc_range(BB)) {
- if (O.shouldKeep())
- continue;
Instruction *Replacement =
dyn_cast_or_null<Instruction>(reduceInstruction(Mod, I));
if (Replacement && Replacement != &I) {
+ if (O.shouldKeep())
+ continue;
+
if (isa<FPMathOperator>(Replacement))
Replacement->copyFastMathFlags(&I);
diff --git a/llvm/tools/llvm-reduce/deltas/ReduceOperands.cpp b/llvm/tools/llvm-reduce/deltas/ReduceOperands.cpp
index 348421b8d6997..98d068f6b1344 100644
--- a/llvm/tools/llvm-reduce/deltas/ReduceOperands.cpp
+++ b/llvm/tools/llvm-reduce/deltas/ReduceOperands.cpp
@@ -34,8 +34,8 @@ extractOperandsFromModule(Oracle &O, Module &Program,
}
for (auto &Op : I.operands()) {
- if (!O.shouldKeep()) {
- if (Value *Reduced = ReduceValue(Op))
+ if (Value *Reduced = ReduceValue(Op)) {
+ if (!O.shouldKeep())
Op.set(Reduced);
}
}
diff --git a/llvm/tools/llvm-reduce/deltas/SimplifyInstructions.cpp b/llvm/tools/llvm-reduce/deltas/SimplifyInstructions.cpp
index 7bf3eb1a07a1a..93556b7e91795 100644
--- a/llvm/tools/llvm-reduce/deltas/SimplifyInstructions.cpp
+++ b/llvm/tools/llvm-reduce/deltas/SimplifyInstructions.cpp
@@ -28,11 +28,11 @@ static void extractInstrFromModule(Oracle &O, Module &Program) {
for (auto &F : Program) {
for (auto &BB : F) {
for (auto &Inst : BB) {
- if (O.shouldKeep())
- continue;
SimplifyQuery Q(DL, &Inst);
if (Value *Simplified = simplifyInstruction(&Inst, Q)) {
+ if (O.shouldKeep())
+ continue;
Inst.replaceAllUsesWith(Simplified);
InstToDelete.push_back(&Inst);
}
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