[gicombiner] Add the run-time rule disable option
Summary:
Each generated helper can be configured to generate an option that disables
rules in that helper. This can be used to bisect rulesets.
The disable bits are stored in a SparseVector as this is very cheap for the
common case where nothing is disabled. It gets more expensive the more rules
are disabled but you're generally doing that for debug purposes where
performance is less of a concern.
Depends on D68426
Reviewers: volkan, bogner
Reviewed By: volkan
Subscribers: hiraditya, Petar.Avramovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68438
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375067 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Target/GlobalISel/Combine.td b/include/llvm/Target/GlobalISel/Combine.td
index 6f38cca..dcac399 100644
--- a/include/llvm/Target/GlobalISel/Combine.td
+++ b/include/llvm/Target/GlobalISel/Combine.td
@@ -32,6 +32,9 @@
: GICombineGroup<rules> {
// The class name to use in the generated output.
string Classname = classname;
+ // The name of a run-time compiler option that will be generated to disable
+ // specific rules within this combiner.
+ string DisableRuleOption = ?;
}
class GICombineRule<dag defs, dag match, dag apply> : GICombine {
/// Defines the external interface of the match rule. This includes:
diff --git a/lib/CodeGen/GlobalISel/Combiner.cpp b/lib/CodeGen/GlobalISel/Combiner.cpp
index 644ce2e..b4562a5 100644
--- a/lib/CodeGen/GlobalISel/Combiner.cpp
+++ b/lib/CodeGen/GlobalISel/Combiner.cpp
@@ -27,6 +27,18 @@
using namespace llvm;
+namespace llvm {
+cl::OptionCategory GICombinerOptionCategory(
+ "GlobalISel Combiner",
+ "Control the rules which are enabled. These options all take a comma "
+ "separated list of rules to disable and may be specified by number "
+ "or number range (e.g. 1-10)."
+#ifndef NDEBUG
+ " They may also be specified by name."
+#endif
+);
+} // end namespace llvm
+
namespace {
/// This class acts as the glue the joins the CombinerHelper to the overall
/// Combine algorithm. The CombinerHelper is intended to report the
diff --git a/lib/Target/AArch64/AArch64Combine.td b/lib/Target/AArch64/AArch64Combine.td
index 8956730..bb99f25 100644
--- a/lib/Target/AArch64/AArch64Combine.td
+++ b/lib/Target/AArch64/AArch64Combine.td
@@ -13,4 +13,6 @@
def AArch64PreLegalizerCombinerHelper: GICombinerHelper<
"AArch64GenPreLegalizerCombinerHelper", [all_combines,
- elide_br_by_inverting_cond]>;
+ elide_br_by_inverting_cond]> {
+ let DisableRuleOption = "aarch64prelegalizercombiner-disable-rule";
+}
diff --git a/lib/Target/AArch64/AArch64PreLegalizerCombiner.cpp b/lib/Target/AArch64/AArch64PreLegalizerCombiner.cpp
index e76db5c..4e3e8e3 100644
--- a/lib/Target/AArch64/AArch64PreLegalizerCombiner.cpp
+++ b/lib/Target/AArch64/AArch64PreLegalizerCombiner.cpp
@@ -47,7 +47,11 @@
GISelKnownBits *KB, MachineDominatorTree *MDT)
: CombinerInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
/*LegalizerInfo*/ nullptr, EnableOpt, OptSize, MinSize),
- KB(KB), MDT(MDT) {}
+ KB(KB), MDT(MDT) {
+ if (!Generated.parseCommandLineOption())
+ report_fatal_error("Invalid rule identifier");
+ }
+
virtual bool combine(GISelChangeObserver &Observer, MachineInstr &MI,
MachineIRBuilder &B) const override;
};
diff --git a/test/CodeGen/AArch64/GlobalISel/prelegalizercombiner-copy-prop-disabled.mir b/test/CodeGen/AArch64/GlobalISel/prelegalizercombiner-copy-prop-disabled.mir
new file mode 100644
index 0000000..bd6756a
--- /dev/null
+++ b/test/CodeGen/AArch64/GlobalISel/prelegalizercombiner-copy-prop-disabled.mir
@@ -0,0 +1,35 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -run-pass=aarch64-prelegalizer-combiner -global-isel -verify-machineinstrs %s -o - \
+# RUN: | FileCheck --check-prefix=ENABLED %s
+# RUN: llc -run-pass=aarch64-prelegalizer-combiner -global-isel -verify-machineinstrs %s -o - \
+# RUN: --aarch64prelegalizercombinerhelper-disable-rule=copy_prop | FileCheck --check-prefix=DISABLED %s
+
+# REQUIRES: asserts
+
+--- |
+ target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+ target triple = "aarch64--"
+ define void @test_copy(i8* %addr) {
+ entry:
+ ret void
+ }
+...
+
+---
+name: test_copy
+body: |
+ bb.0.entry:
+ liveins: $x0
+ ; ENABLED-LABEL: name: test_copy
+ ; ENABLED: [[COPY:%[0-9]+]]:_(p0) = COPY $x0
+ ; ENABLED: $x0 = COPY [[COPY]](p0)
+ ; DISABLED-LABEL: name: test_copy
+ ; DISABLED: [[COPY:%[0-9]+]]:_(p0) = COPY $x0
+ ; DISABLED: [[COPY1:%[0-9]+]]:_(p0) = COPY [[COPY]](p0)
+ ; DISABLED: [[COPY2:%[0-9]+]]:_(p0) = COPY [[COPY1]](p0)
+ ; DISABLED: $x0 = COPY [[COPY2]](p0)
+ %0:_(p0) = COPY $x0
+ %1:_(p0) = COPY %0
+ %2:_(p0) = COPY %1
+ $x0 = COPY %2
+...
diff --git a/utils/TableGen/GICombinerEmitter.cpp b/utils/TableGen/GICombinerEmitter.cpp
index 676decc..f243725 100644
--- a/utils/TableGen/GICombinerEmitter.cpp
+++ b/utils/TableGen/GICombinerEmitter.cpp
@@ -15,6 +15,7 @@
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Timer.h"
#include "llvm/TableGen/Error.h"
+#include "llvm/TableGen/StringMatcher.h"
#include "llvm/TableGen/TableGenBackend.h"
#include "CodeGenTarget.h"
#include "GlobalISel/CodeExpander.h"
@@ -75,6 +76,8 @@
bool parseDefs();
bool parseMatcher(const CodeGenTarget &Target);
+ RuleID getID() const { return ID; }
+ StringRef getName() const { return TheDef.getName(); }
const Record &getDef() const { return TheDef; }
const CodeInit *getMatchingFixupCode() const { return MatchingFixupCode; }
size_t getNumRoots() const { return Roots.size(); }
@@ -202,6 +205,9 @@
}
void run(raw_ostream &OS);
+ /// Emit the name matcher (guarded by #ifndef NDEBUG) used to disable rules in
+ /// response to the generated cl::opt.
+ void emitNameMatcher(raw_ostream &OS) const;
void generateCodeForRule(raw_ostream &OS, const CombineRule *Rule,
StringRef Indent) const;
};
@@ -211,6 +217,32 @@
StringRef Name, Record *Combiner)
: Name(Name), Target(Target), Combiner(Combiner) {}
+void GICombinerEmitter::emitNameMatcher(raw_ostream &OS) const {
+ std::vector<std::pair<std::string, std::string>> Cases;
+ Cases.reserve(Rules.size());
+
+ for (const CombineRule &EnumeratedRule : make_pointee_range(Rules)) {
+ std::string Code;
+ raw_string_ostream SS(Code);
+ SS << "return " << EnumeratedRule.getID() << ";\n";
+ Cases.push_back(std::make_pair(EnumeratedRule.getName(), SS.str()));
+ }
+
+ OS << "#ifndef NDEBUG\n"
+ << "static Optional<uint64_t> getRuleIdxForIdentifier(StringRef "
+ "RuleIdentifier) {\n"
+ << " uint64_t I;\n"
+ << " // getAtInteger(...) returns false on success\n"
+ << " bool Parsed = !RuleIdentifier.getAsInteger(0, I);\n"
+ << " if (Parsed)\n"
+ << " return I;\n\n";
+ StringMatcher Matcher("RuleIdentifier", Cases, OS);
+ Matcher.Emit();
+ OS << " return None;\n"
+ << "}\n"
+ << "#endif // ifndef NDEBUG\n\n";
+}
+
std::unique_ptr<CombineRule>
GICombinerEmitter::makeCombineRule(const Record &TheDef) {
std::unique_ptr<CombineRule> Rule =
@@ -254,7 +286,7 @@
const Record &RuleDef = Rule->getDef();
OS << Indent << "// Rule: " << RuleDef.getName() << "\n"
- << Indent << "{\n";
+ << Indent << "if (!isRuleDisabled(" << Rule->getID() << ")) {\n";
CodeExpansions Expansions;
for (const RootInfo &Root : Rule->roots()) {
@@ -309,21 +341,83 @@
"Code Generation", "Time spent generating code",
TimeRegions);
OS << "#ifdef " << Name.upper() << "_GENCOMBINERHELPER_DEPS\n"
+ << "#include \"llvm/ADT/SparseBitVector.h\"\n"
+ << "namespace llvm {\n"
+ << "extern cl::OptionCategory GICombinerOptionCategory;\n"
+ << "} // end namespace llvm\n"
<< "#endif // ifdef " << Name.upper() << "_GENCOMBINERHELPER_DEPS\n\n";
OS << "#ifdef " << Name.upper() << "_GENCOMBINERHELPER_H\n"
<< "class " << getClassName() << " {\n"
+ << " SparseBitVector<> DisabledRules;\n"
+ << "\n"
<< "public:\n"
+ << " bool parseCommandLineOption();\n"
+ << " bool isRuleDisabled(unsigned ID) const;\n"
+ << " bool setRuleDisabled(StringRef RuleIdentifier);\n"
+ << "\n"
<< " bool tryCombineAll(\n"
<< " GISelChangeObserver &Observer,\n"
<< " MachineInstr &MI,\n"
<< " MachineIRBuilder &B) const;\n"
- << "};\n";
+ << "};\n\n";
+
+ emitNameMatcher(OS);
+
+ OS << "bool " << getClassName()
+ << "::setRuleDisabled(StringRef RuleIdentifier) {\n"
+ << " std::pair<StringRef, StringRef> RangePair = "
+ "RuleIdentifier.split('-');\n"
+ << " if (!RangePair.second.empty()) {\n"
+ << " const auto First = getRuleIdxForIdentifier(RangePair.first);\n"
+ << " const auto Last = getRuleIdxForIdentifier(RangePair.second);\n"
+ << " if (!First.hasValue() || !Last.hasValue())\n"
+ << " return false;\n"
+ << " if (First >= Last)\n"
+ << " report_fatal_error(\"Beginning of range should be before end of "
+ "range\");\n"
+ << " for (auto I = First.getValue(); I < Last.getValue(); ++I)\n"
+ << " DisabledRules.set(I);\n"
+ << " return true;\n"
+ << " }\n"
+ << "#ifndef NDEBUG\n"
+ << " else {\n"
+ << " const auto I = getRuleIdxForIdentifier(RangePair.first);\n"
+ << " if (!I.hasValue())\n"
+ << " return false;\n"
+ << " DisabledRules.set(I.getValue());\n"
+ << " return true;\n"
+ << " }\n"
+ << "#else // ifndef NDEBUG\n"
+ << " llvm_unreachable(\"Cannot disable rules in non-asserts builds\");\n"
+ << " return false;\n"
+ << "#endif // ifndef NDEBUG\n\n"
+ << "}\n";
+
+ OS << "bool " << getClassName()
+ << "::isRuleDisabled(unsigned RuleID) const {\n"
+ << " return DisabledRules.test(RuleID);\n"
+ << "}\n";
OS << "#endif // ifdef " << Name.upper() << "_GENCOMBINERHELPER_H\n\n";
OS << "#ifdef " << Name.upper() << "_GENCOMBINERHELPER_CPP\n"
<< "\n"
- << "bool " << getClassName() << "::tryCombineAll(\n"
+ << "cl::list<std::string> " << Name << "Option(\n"
+ << " \"" << Name.lower() << "-disable-rule\",\n"
+ << " cl::desc(\"Disable one or more combiner rules temporarily in "
+ << "the " << Name << " pass\"),\n"
+ << " cl::CommaSeparated,\n"
+ << " cl::Hidden,\n"
+ << " cl::cat(GICombinerOptionCategory));\n"
+ << "\n"
+ << "bool " << getClassName() << "::parseCommandLineOption() {\n"
+ << " for (const auto &Identifier : " << Name << "Option)\n"
+ << " if (!setRuleDisabled(Identifier))\n"
+ << " return false;\n"
+ << " return true;\n"
+ << "}\n\n";
+
+ OS << "bool " << getClassName() << "::tryCombineAll(\n"
<< " GISelChangeObserver &Observer,\n"
<< " MachineInstr &MI,\n"
<< " MachineIRBuilder &B) const {\n"
