88419a30a0
During scalar promotion, if there are additional potentially-aliasing
loads outside the promoted set, we can still perform a load-only
promotion. As the stores are retained, any potentially-aliasing
loads will still read the correct value.
This increases the number of load promotions in llvm-test-suite by
a factor of two:
| Old | New
licm.NumPromotionCandidates | 4448 | 6038
licm.NumLoadPromoted | 479 | 1069
licm.NumLoadStorePromoted | 1459 | 1459
Unfortunately, this does have some impact on compile-time:
http://llvm-compile-time-tracker.com/compare.php?from=57f7f0d6cf0706a88e1ecb74f3d3e8891cceabfa&to=72b811738148aab399966a0435f13b695da1c1c8&stat=instructions
In part this is because we now have less early bailouts from
promotion, but also due to second order effects (e.g. for one case
I looked at we spend more time in SLP now).
Differential Revision: https://reviews.llvm.org/D133192
93 lines
2.7 KiB
C++
93 lines
2.7 KiB
C++
//=======- AliasSetTrackerTest.cpp - Unit test for the Alias Set Tracker -===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/AliasSetTracker.h"
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#include "llvm/ADT/Triple.h"
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/Analysis/TargetLibraryInfo.h"
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#include "llvm/Analysis/TypeBasedAliasAnalysis.h"
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#include "llvm/AsmParser/Parser.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/Module.h"
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#include "llvm/Support/SourceMgr.h"
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#include "gtest/gtest.h"
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using namespace llvm;
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TEST(AliasSetTracker, AliasUnknownInst) {
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StringRef Assembly = R"(
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@a = common global i32 0, align 4
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@b = common global float 0.000000e+00, align 4
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; Function Attrs: nounwind ssp uwtable
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define i32 @read_a() #0 {
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%1 = load i32, i32* @a, align 4, !tbaa !3
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ret i32 %1
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}
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; Function Attrs: nounwind ssp uwtable
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define void @write_b() #0 {
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store float 1.000000e+01, float* @b, align 4, !tbaa !7
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ret void
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}
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; Function Attrs: nounwind ssp uwtable
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define void @test() #0 {
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%1 = call i32 @read_a(), !tbaa !3
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call void @write_b(), !tbaa !7
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ret void
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}
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!3 = !{!4, !4, i64 0}
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!4 = !{!"int", !5, i64 0}
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!5 = !{!"omnipotent char", !6, i64 0}
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!6 = !{!"Simple C/C++ TBAA"}
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!7 = !{!8, !8, i64 0}
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!8 = !{!"float", !5, i64 0}
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)";
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// Parse the IR. The two calls in @test can not access aliasing elements.
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LLVMContext Context;
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SMDiagnostic Error;
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auto M = parseAssemblyString(Assembly, Error, Context);
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ASSERT_TRUE(M) << "Bad assembly?";
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// Initialize the alias result.
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Triple Trip(M->getTargetTriple());
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TargetLibraryInfoImpl TLII(Trip);
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TargetLibraryInfo TLI(TLII);
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AAResults AA(TLI);
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TypeBasedAAResult TBAAR;
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AA.addAAResult(TBAAR);
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// Initialize the alias set tracker for the @test function.
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Function *Test = M->getFunction("test");
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ASSERT_NE(Test, nullptr);
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BatchAAResults BAA(AA);
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AliasSetTracker AST(BAA);
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for (auto &BB : *Test)
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AST.add(BB);
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// There should be 2 disjoint alias sets. 1 from each call.
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ASSERT_EQ((int)AST.getAliasSets().size(), 2);
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// Directly test aliasesUnknownInst.
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// Now every call instruction should only alias one alias set.
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BatchAAResults BatchAA(AA);
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for (auto &Inst : *Test->begin()) {
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bool FoundAS = false;
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for (AliasSet &AS : AST) {
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if (!Inst.mayReadOrWriteMemory())
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continue;
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if (!isModOrRefSet(AS.aliasesUnknownInst(&Inst, BatchAA)))
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continue;
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ASSERT_NE(FoundAS, true);
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FoundAS = true;
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}
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}
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}
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