[flang] [clang] [flang] (Re-)Enable alias tags pass by default (PR #74250)
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Sun Dec 3 12:46:14 PST 2023
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang-driver
Author: Tom Eccles (tblah)
<details>
<summary>Changes</summary>
Enable by default for optimization levels higher than 0 (same behavior as clang).
For simplicity, only forward the flag to the frontend driver when it contradicts what is implied by the optimization level.
This was first landed in
https://github.com/llvm/llvm-project/pull/73111 but was later reverted due to a performance regression. That regression was fixed by https://github.com/llvm/llvm-project/pull/74065.
---
Full diff: https://github.com/llvm/llvm-project/pull/74250.diff
8 Files Affected:
- (modified) clang/lib/Driver/ToolChains/Flang.cpp (+20)
- (modified) flang/include/flang/Tools/CLOptions.inc (+3-3)
- (modified) flang/lib/Frontend/CompilerInvocation.cpp (+6-4)
- (modified) flang/test/Driver/falias-analysis.f90 (+15-1)
- (modified) flang/test/Driver/mlir-pass-pipeline.f90 (+2)
- (modified) flang/test/Driver/optimization-remark.f90 (+9-13)
- (modified) flang/test/Fir/basic-program.fir (+4)
- (modified) flang/tools/tco/tco.cpp (+1)
``````````diff
diff --git a/clang/lib/Driver/ToolChains/Flang.cpp b/clang/lib/Driver/ToolChains/Flang.cpp
index 98b337e60e4ff..0319f1a117111 100644
--- a/clang/lib/Driver/ToolChains/Flang.cpp
+++ b/clang/lib/Driver/ToolChains/Flang.cpp
@@ -143,6 +143,26 @@ void Flang::addCodegenOptions(const ArgList &Args,
if (shouldLoopVersion(Args))
CmdArgs.push_back("-fversion-loops-for-stride");
+ Arg *aliasAnalysis = Args.getLastArg(options::OPT_falias_analysis,
+ options::OPT_fno_alias_analysis);
+ // only pass on the argument if it does not match that implied by the
+ // optimization level: so if optimization is requested, only forward
+ // -fno-alias-analysis. If optimization is not requested, only forward
+ // -falias-analysis.
+ Arg *optLevel =
+ Args.getLastArg(options::OPT_Ofast, options::OPT_O, options::OPT_O4);
+ if (aliasAnalysis) {
+ bool faliasAnalysis =
+ aliasAnalysis->getOption().matches(options::OPT_falias_analysis);
+ if (optLevel && !faliasAnalysis) {
+ CmdArgs.push_back("-fno-alias-analysis");
+ } else {
+ if (faliasAnalysis)
+ // requested alias analysis but no optimization enabled
+ CmdArgs.push_back("-falias-analysis");
+ }
+ }
+
Args.addAllArgs(CmdArgs, {options::OPT_flang_experimental_hlfir,
options::OPT_flang_deprecated_no_hlfir,
options::OPT_flang_experimental_polymorphism,
diff --git a/flang/include/flang/Tools/CLOptions.inc b/flang/include/flang/Tools/CLOptions.inc
index c452c023b4a80..d3e4dc6cd4a24 100644
--- a/flang/include/flang/Tools/CLOptions.inc
+++ b/flang/include/flang/Tools/CLOptions.inc
@@ -158,10 +158,10 @@ inline void addDebugFoundationPass(mlir::PassManager &pm) {
}
inline void addFIRToLLVMPass(
- mlir::PassManager &pm, llvm::OptimizationLevel optLevel = defaultOptLevel) {
+ mlir::PassManager &pm, const MLIRToLLVMPassPipelineConfig &config) {
fir::FIRToLLVMPassOptions options;
options.ignoreMissingTypeDescriptors = ignoreMissingTypeDescriptors;
- options.applyTBAA = optLevel.isOptimizingForSpeed();
+ options.applyTBAA = config.AliasAnalysis;
options.forceUnifiedTBAATree = useOldAliasTags;
addPassConditionally(pm, disableFirToLlvmIr,
[&]() { return fir::createFIRToLLVMPass(options); });
@@ -311,7 +311,7 @@ inline void createDefaultFIRCodeGenPassPipeline(
if (config.VScaleMin != 0)
pm.addPass(fir::createVScaleAttrPass({config.VScaleMin, config.VScaleMax}));
- fir::addFIRToLLVMPass(pm, config.OptLevel);
+ fir::addFIRToLLVMPass(pm, config);
}
/// Create a pass pipeline for lowering from MLIR to LLVM IR
diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index e7730d50dc1bd..ec04727fb2641 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -242,10 +242,12 @@ static void parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts,
clang::driver::options::OPT_fno_loop_versioning, false))
opts.LoopVersioning = 1;
- opts.AliasAnalysis =
- args.hasFlag(clang::driver::options::OPT_falias_analysis,
- clang::driver::options::OPT_fno_alias_analysis,
- /*default=*/false);
+ opts.AliasAnalysis = opts.OptimizationLevel > 0;
+ if (auto *arg =
+ args.getLastArg(clang::driver::options::OPT_falias_analysis,
+ clang::driver::options::OPT_fno_alias_analysis))
+ opts.AliasAnalysis =
+ arg->getOption().matches(clang::driver::options::OPT_falias_analysis);
for (auto *a : args.filtered(clang::driver::options::OPT_fpass_plugin_EQ))
opts.LLVMPassPlugins.push_back(a->getValue());
diff --git a/flang/test/Driver/falias-analysis.f90 b/flang/test/Driver/falias-analysis.f90
index f2c5dbde6d2c8..3bd389c33dbc5 100644
--- a/flang/test/Driver/falias-analysis.f90
+++ b/flang/test/Driver/falias-analysis.f90
@@ -2,12 +2,26 @@
! See flang/test/Fir/tbaa-codegen.fir for a test that the output is correct
! RUN: %flang -c -emit-llvm -falias-analysis %s -o - | llvm-dis | FileCheck %s --check-prefix=CHECK-AA --check-prefix=CHECK-ALL
-! RUN: %flang -c -emit-llvm -falias-analysis -fno-alias-analysis %s -o - | llvm-dis | FileCheck %s --check-prefix=CHECK-NOAA --check-prefix=CHECK-ALL
+! RUN: %flang -c -emit-llvm -Ofast %s -o - | llvm-dis | FileCheck %s --check-prefix=CHECK-AA --check-prefix=CHECK-ALL
+! RUN: %flang -c -emit-llvm -O3 %s -o - | llvm-dis | FileCheck %s --check-prefix=CHECK-AA --check-prefix=CHECK-ALL
+! RUN: %flang -c -emit-llvm -O2 %s -o - | llvm-dis | FileCheck %s --check-prefix=CHECK-AA --check-prefix=CHECK-ALL
+! RUN: %flang -c -emit-llvm -O1 %s -o - | llvm-dis | FileCheck %s --check-prefix=CHECK-AA --check-prefix=CHECK-ALL
+
+! RUN: %flang -c -emit-llvm -O0 %s -o - | llvm-dis | FileCheck %s --check-prefix=CHECK-NOAA --check-prefix=CHECK-ALL
+! RUN: %flang -c -emit-llvm -Ofast -fno-alias-analysis %s -o - | llvm-dis | FileCheck %s --check-prefix=CHECK-NOAA --check-prefix=CHECK-ALL
+! RUN: %flang -c -emit-llvm -fno-alias-analysis -Ofast %s -o - | llvm-dis | FileCheck %s --check-prefix=CHECK-NOAA --check-prefix=CHECK-ALL
! RUN: %flang -c -emit-llvm %s -o - | llvm-dis | FileCheck %s --check-prefix=CHECK-NOAA --check-prefix=CHECK-ALL
+! RUN: %flang -c -emit-llvm -falias-analysis -fno-alias-analysis %s -o - | llvm-dis | FileCheck %s --check-prefix=CHECK-NOAA --check-prefix=CHECK-ALL
! RUN: %flang -fc1 -emit-llvm -falias-analysis %s -o - | FileCheck %s --check-prefix=CHECK-AA --check-prefix=CHECK-ALL
+! RUN: %flang -fc1 -emit-llvm -O3 %s -o - | FileCheck %s --check-prefix=CHECK-AA --check-prefix=CHECK-ALL
+! RUN: %flang -fc1 -emit-llvm -O2 %s -o - | FileCheck %s --check-prefix=CHECK-AA --check-prefix=CHECK-ALL
+! RUN: %flang -fc1 -emit-llvm -O1 %s -o - | FileCheck %s --check-prefix=CHECK-AA --check-prefix=CHECK-ALL
+
+! RUN: %flang -fc1 -emit-llvm -O0 %s -o - | FileCheck %s --check-prefix=CHECK-NOAA --check-prefix=CHECK-ALL
! RUN: %flang -fc1 -emit-llvm -falias-analysis -fno-alias-analysis %s -o - | FileCheck %s --check-prefix=CHECK-NOAA --check-prefix=CHECK-ALL
! RUN: %flang -fc1 -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK-NOAA --check-prefix=CHECK-ALL
+! RUN: %flang -fc1 -emit-llvm -O3 -fno-alias-analysis %s -o - | FileCheck %s --check-prefix=CHECK-NOAA --check-prefix=CHECK-ALL
subroutine simple(a)
integer, intent(inout) :: a(:)
diff --git a/flang/test/Driver/mlir-pass-pipeline.f90 b/flang/test/Driver/mlir-pass-pipeline.f90
index 7f92ec25bef98..3d8c42f123e2e 100644
--- a/flang/test/Driver/mlir-pass-pipeline.f90
+++ b/flang/test/Driver/mlir-pass-pipeline.f90
@@ -51,6 +51,8 @@
! ALL-NEXT: 'func.func' Pipeline
! ALL-NEXT: PolymorphicOpConversion
+! O2-NEXT: AddAliasTags
+! O2-NEXT: 'func.func' Pipeline
! ALL-NEXT: CFGConversion
! ALL-NEXT: SCFToControlFlow
diff --git a/flang/test/Driver/optimization-remark.f90 b/flang/test/Driver/optimization-remark.f90
index 13fc24346eac6..e90baa892f46a 100644
--- a/flang/test/Driver/optimization-remark.f90
+++ b/flang/test/Driver/optimization-remark.f90
@@ -41,28 +41,24 @@
! Once we start filtering, this is reduced to 1 one of the loop passes.
! PASS-REGEX-LOOP-ONLY-NOT: optimization-remark.f90:77:7: remark: hoisting load [-Rpass=licm]
-! PASS-REGEX-LOOP-ONLY: optimization-remark.f90:83:5: remark: Loop deleted because it is invariant [-Rpass=loop-delete]
+! PASS-REGEX-LOOP-ONLY: optimization-remark.f90:79:5: remark: Loop deleted because it is invariant [-Rpass=loop-delete]
! MISSED-REGEX-LOOP-ONLY-NOT: optimization-remark.f90:77:7: remark: failed to hoist load with loop-invariant address because load is conditionally executed [-Rpass-missed=licm]
-! MISSED-REGEX-LOOP-ONLY: optimization-remark.f90:76:4: remark: loop not vectorized [-Rpass-missed=loop-vectorize]
+! MISSED-REGEX-LOOP-ONLY: optimization-remark.f90:72:4: remark: loop not vectorized [-Rpass-missed=loop-vectorize]
-! ANALYSIS-REGEX-LOOP-ONLY: optimization-remark.f90:79:7: remark: loop not vectorized: unsafe dependent memory operations in loop. Use #pragma clang loop distribute(enable) to allow loop distribution to attempt to isolate the offending operations into a separate loop
-! ANALYSIS-REGEX-LOOP-ONLY: Unknown data dependence. Memory location is the same as accessed at optimization-remark.f90:78:7 [-Rpass-analysis=loop-vectorize]
+! ANALYSIS-REGEX-LOOP-ONLY: optimization-remark.f90:74:7: remark: loop not vectorized: unsafe dependent memory operations in loop
! ANALYSIS-REGEX-LOOP-ONLY-NOT: remark: {{.*}}: IR instruction count changed from {{[0-9]+}} to {{[0-9]+}}; Delta: {{-?[0-9]+}} [-Rpass-analysis=size-info]
-! PASS: optimization-remark.f90:77:7: remark: hoisting load [-Rpass=licm]
-! PASS: optimization-remark.f90:83:5: remark: Loop deleted because it is invariant [-Rpass=loop-delete]
+! PASS: optimization-remark.f90:79:5: remark: Loop deleted because it is invariant [-Rpass=loop-delete]
-! MISSED: optimization-remark.f90:77:7: remark: failed to hoist load with loop-invariant address because load is conditionally executed [-Rpass-missed=licm]
-! MISSED: optimization-remark.f90:76:4: remark: loop not vectorized [-Rpass-missed=loop-vectorize]
-! MISSED-NOT: optimization-remark.f90:79:7: remark: loop not vectorized: unsafe dependent memory operations in loop. Use #pragma clang loop distribute(enable) to allow loop distribution to attempt to isolate the offending operations into a separate loop
+! MISSED: optimization-remark.f90:73:7: remark: failed to hoist load with loop-invariant address
+! MISSED: optimization-remark.f90:72:4: remark: loop not vectorized [-Rpass-missed=loop-vectorize]
+! MISSED-NOT: optimization-remark.f90:75:7: remark: loop not vectorized: unsafe dependent memory operations in loop. Use #pragma clang loop distribute(enable) to allow loop distribution to attempt to isolate the offending operations into a separate loop
! MISSED-NOT: Unknown data dependence. Memory location is the same as accessed at optimization-remark.f90:78:7 [-Rpass-analysis=loop-vectorize]
-! ANALYSIS: optimization-remark.f90:79:7: remark: loop not vectorized: unsafe dependent memory operations in loop. Use #pragma clang loop distribute(enable) to allow loop distribution to attempt to isolate the offending operations into a separate loop
-! ANALYSIS: Unknown data dependence. Memory location is the same as accessed at optimization-remark.f90:78:7 [-Rpass-analysis=loop-vectorize]
-! ANALYSIS: remark: {{.*}}: IR instruction count changed from {{[0-9]+}} to {{[0-9]+}}; Delta: {{-?[0-9]+}} [-Rpass-analysis=size-info]
-! ANALYSIS-NOT: optimization-remark.f90:77:7: remark: failed to hoist load with loop-invariant address because load is conditionally executed [-Rpass-missed=licm]
+! ANALYSIS: optimization-remark.f90:74:7: remark: loop not vectorized: unsafe dependent memory operations in loop.
+! ANALYSIS: remark: {{.*}} instructions in function [-Rpass-analysis=asm-printer]
subroutine swap_real(a1, a2)
implicit none
diff --git a/flang/test/Fir/basic-program.fir b/flang/test/Fir/basic-program.fir
index 0e82f7dfdedb4..d8a9e74c318ce 100644
--- a/flang/test/Fir/basic-program.fir
+++ b/flang/test/Fir/basic-program.fir
@@ -57,6 +57,10 @@ func.func @_QQmain() {
// PASSES-NEXT: 'func.func' Pipeline
// PASSES-NEXT: PolymorphicOpConversion
+
+// PASSES-NEXT: AddAliasTags
+
+// PASSES-NEXT: 'func.func' Pipeline
// PASSES-NEXT: CFGConversion
// PASSES-NEXT: SCFToControlFlow
diff --git a/flang/tools/tco/tco.cpp b/flang/tools/tco/tco.cpp
index 31d6bac142dc4..a649535a39b74 100644
--- a/flang/tools/tco/tco.cpp
+++ b/flang/tools/tco/tco.cpp
@@ -120,6 +120,7 @@ compileFIR(const mlir::PassPipelineCLParser &passPipeline) {
return mlir::failure();
} else {
MLIRToLLVMPassPipelineConfig config(llvm::OptimizationLevel::O2);
+ config.AliasAnalysis = true; // enabled when optimizing for speed
if (codeGenLLVM) {
// Run only CodeGen passes.
fir::createDefaultFIRCodeGenPassPipeline(pm, config);
``````````
</details>
https://github.com/llvm/llvm-project/pull/74250
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