[llvm] r304453 - [Profile] Fix builtin_expect lowering bug
Dimitry Andric via llvm-commits
llvm-commits at lists.llvm.org
Fri Jun 2 05:33:43 PDT 2017
Minimized test case:
/* clang -cc1 -triple x86_64 -S -O1 test-int128.c */
__int128 a;
void c();
void b() {
if (a == -1)
c();
}
Results in:
Assertion failed: (getActiveBits() <= 64 && "Too many bits for uint64_t"), function getZExtValue, file include/llvm/ADT/APInt.h, line 1526.
Program received signal SIGABRT, Aborted.
0x00000008046815da in thr_kill () from /lib/libc.so.7
(gdb) bt
#0 0x00000008046815da in thr_kill () from /lib/libc.so.7
#1 0x00000008046815a4 in raise () from /lib/libc.so.7
#2 0x0000000804681519 in abort () from /lib/libc.so.7
#3 0x00000008046fd371 in __assert () from /lib/libc.so.7
#4 0x000000000112cce0 in lowerExpectIntrinsic(llvm::Function&) ()
#5 0x0000000000e41b8a in llvm::FPPassManager::runOnFunction(llvm::Function&) ()
#6 0x0000000000e41319 in llvm::legacy::FunctionPassManagerImpl::run(llvm::Function&) ()
#7 0x0000000000e4119c in llvm::legacy::FunctionPassManager::run(llvm::Function&) ()
#8 0x00000000013d0dac in clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::DataLayout const&, llvm::Module*, clang::BackendAction, std::__1::unique_ptr<llvm::raw_pwrite_stream, std::__1::default_delete<llvm::raw_pwrite_stream> >) ()
#9 0x0000000001a7c2ca in clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) ()
#10 0x0000000001d2cbe2 in clang::ParseAST(clang::Sema&, bool, bool) ()
#11 0x000000000175d99c in clang::FrontendAction::Execute() ()
#12 0x0000000001725c31 in clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) ()
#13 0x00000000017dadb3 in clang::ExecuteCompilerInvocation(clang::CompilerInstance*) ()
#14 0x0000000000721972 in cc1_main(llvm::ArrayRef<char const*>, char const*, void*) ()
#15 0x000000000071fbc9 in main ()
-Dimitry
> On 2 Jun 2017, at 00:59, Xinliang David Li via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>
> working on it.
>
> On Thu, Jun 1, 2017 at 3:37 PM, Vedant Kumar <vsk at apple.com> wrote:
> Hi David,
>
> I think this commit is causing a failure in the compiler-rt tests:
> http://green.lab.llvm.org/green//job/clang-stage1-cmake-RA-expensive/6811
>
> Could you take a look?
>
> thanks,
> vedant
>
>> On Jun 1, 2017, at 12:05 PM, Xinliang David Li via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>>
>> Author: davidxl
>> Date: Thu Jun 1 14:05:55 2017
>> New Revision: 304453
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=304453&view=rev
>> Log:
>> [Profile] Fix builtin_expect lowering bug
>>
>> The lowerer wrongly assumes the ICMP instruction
>> 1) always has a constant operand;
>> 2) the operand has value 0.
>>
>> It also assumes the expected value can only be one, thus
>> other values other than one will be considered 'zero'.
>>
>> This leads to wrong profile annotation when other integer values
>> are used other than 0, 1 in the comparison or in the expect intrinsic.
>>
>> Also missing is handling of equal predicate.
>>
>> This patch fixes all the above problems.
>>
>> Differential Revision: http://reviews.llvm.org/D33757
>>
>> Added:
>> llvm/trunk/test/Transforms/LowerExpectIntrinsic/expect_nonboolean.ll
>> Modified:
>> llvm/trunk/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp
>>
>> Modified: llvm/trunk/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp?rev=304453&r1=304452&r2=304453&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp (original)
>> +++ llvm/trunk/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp Thu Jun 1 14:05:55 2017
>> @@ -98,11 +98,20 @@ template <class BrSelInst> static bool h
>> CallInst *CI;
>>
>> ICmpInst *CmpI = dyn_cast<ICmpInst>(BSI.getCondition());
>> + CmpInst::Predicate Predicate;
>> + uint64_t ValueComparedTo = 0;
>> if (!CmpI) {
>> CI = dyn_cast<CallInst>(BSI.getCondition());
>> + Predicate = CmpInst::ICMP_NE;
>> + ValueComparedTo = 0;
>> } else {
>> - if (CmpI->getPredicate() != CmpInst::ICMP_NE)
>> + Predicate = CmpI->getPredicate();
>> + if (Predicate != CmpInst::ICMP_NE && Predicate != CmpInst::ICMP_EQ)
>> return false;
>> + ConstantInt *CmpConstOperand = dyn_cast<ConstantInt>(CmpI->getOperand(1));
>> + if (!CmpConstOperand)
>> + return false;
>> + ValueComparedTo = CmpConstOperand->getZExtValue();
>> CI = dyn_cast<CallInst>(CmpI->getOperand(0));
>> }
>>
>> @@ -121,9 +130,8 @@ template <class BrSelInst> static bool h
>> MDBuilder MDB(CI->getContext());
>> MDNode *Node;
>>
>> - // If expect value is equal to 1 it means that we are more likely to take
>> - // branch 0, in other case more likely is branch 1.
>> - if (ExpectedValue->isOne())
>> + if ((ExpectedValue->getZExtValue() == ValueComparedTo) ==
>> + (Predicate == CmpInst::ICMP_EQ))
>> Node = MDB.createBranchWeights(LikelyBranchWeight, UnlikelyBranchWeight);
>> else
>> Node = MDB.createBranchWeights(UnlikelyBranchWeight, LikelyBranchWeight);
>>
>> Added: llvm/trunk/test/Transforms/LowerExpectIntrinsic/expect_nonboolean.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LowerExpectIntrinsic/expect_nonboolean.ll?rev=304453&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/Transforms/LowerExpectIntrinsic/expect_nonboolean.ll (added)
>> +++ llvm/trunk/test/Transforms/LowerExpectIntrinsic/expect_nonboolean.ll Thu Jun 1 14:05:55 2017
>> @@ -0,0 +1,104 @@
>> +; RUN: opt -lower-expect -S -o - < %s | FileCheck %s
>> +; RUN: opt -S -passes='function(lower-expect)' < %s | FileCheck %s
>> +
>> +define i32 @foo(i32 %arg) #0 {
>> +; CHECK-LABEL: @foo(i32{{.*}})
>> +bb:
>> + %tmp = sext i32 %arg to i64
>> + %tmp1 = call i64 @llvm.expect.i64(i64 %tmp, i64 4)
>> + %tmp2 = icmp ne i64 %tmp1, 0
>> + br i1 %tmp2, label %bb3, label %bb5
>> +; CHECK: br i1 %tmp2{{.*}}!prof [[LIKELY:![0-9]+]]
>> +
>> +bb3: ; preds = %bb
>> + %tmp4 = call i32 (...) @bar()
>> + br label %bb5
>> +
>> +bb5: ; preds = %bb3, %bb
>> + ret i32 1
>> +}
>> +
>> +define i32 @foo2(i32 %arg) #0 {
>> +; CHECK-LABEL: @foo2
>> +bb:
>> + %tmp = sext i32 %arg to i64
>> + %tmp1 = call i64 @llvm.expect.i64(i64 %tmp, i64 4)
>> + %tmp2 = icmp eq i64 %tmp1, 2
>> + br i1 %tmp2, label %bb3, label %bb5
>> +; CHECK: br i1 %tmp2{{.*}}!prof [[UNLIKELY:![0-9]+]]
>> +
>> +bb3: ; preds = %bb
>> + %tmp4 = call i32 (...) @bar()
>> + br label %bb5
>> +
>> +bb5: ; preds = %bb3, %bb
>> + ret i32 1
>> +}
>> +
>> +define i32 @foo3(i32 %arg) #0 {
>> +; CHECK-LABEL: @foo3
>> +bb:
>> + %tmp = sext i32 %arg to i64
>> + %tmp1 = call i64 @llvm.expect.i64(i64 %tmp, i64 4)
>> + %tmp2 = icmp eq i64 %tmp1, 4
>> + br i1 %tmp2, label %bb3, label %bb5
>> +; CHECK: br i1 %tmp2{{.*}}!prof [[LIKELY]]
>> +
>> +bb3: ; preds = %bb
>> + %tmp4 = call i32 (...) @bar()
>> + br label %bb5
>> +
>> +bb5: ; preds = %bb3, %bb
>> + ret i32 1
>> +}
>> +
>> +define i32 @foo4(i32 %arg) #0 {
>> +; CHECK-LABEL: @foo4
>> +bb:
>> + %tmp = sext i32 %arg to i64
>> + %tmp1 = call i64 @llvm.expect.i64(i64 %tmp, i64 4)
>> + %tmp2 = icmp ne i64 %tmp1, 2
>> + br i1 %tmp2, label %bb3, label %bb5
>> +; CHECK: br i1 %tmp2{{.*}}!prof [[LIKELY]]
>> +
>> +bb3: ; preds = %bb
>> + %tmp4 = call i32 (...) @bar()
>> + br label %bb5
>> +
>> +bb5: ; preds = %bb3, %bb
>> + ret i32 1
>> +}
>> +
>> +define i32 @foo5(i32 %arg, i32 %arg1) #0 {
>> +; CHECK-LABEL: @foo5
>> +bb:
>> + %tmp = sext i32 %arg1 to i64
>> + %tmp2 = call i64 @llvm.expect.i64(i64 %tmp, i64 4)
>> + %tmp3 = sext i32 %arg to i64
>> + %tmp4 = icmp ne i64 %tmp2, %tmp3
>> + br i1 %tmp4, label %bb5, label %bb7
>> +; CHECK-NOT: !prof
>> +
>> +bb5: ; preds = %bb
>> + %tmp6 = call i32 (...) @bar()
>> + br label %bb7
>> +
>> +bb7: ; preds = %bb5, %bb
>> + ret i32 1
>> +}
>> +
>> +declare i64 @llvm.expect.i64(i64, i64) #1
>> +
>> +declare i32 @bar(...) local_unnamed_addr #0
>> +
>> +attributes #0 = { nounwind uwtable }
>> +attributes #1 = { nounwind readnone }
>> +
>> +!llvm.module.flags = !{!0}
>> +!llvm.ident = !{!1}
>> +
>> +!0 = !{i32 1, !"wchar_size", i32 4}
>> +!1 = !{!"clang version 5.0.0 (trunk 304373)"}
>> +; CHECK: [[LIKELY]] = !{!"branch_weights", i32 2000, i32 1}
>> +; CHECK: [[UNLIKELY]] = !{!"branch_weights", i32 1, i32 2000}
>> +
>>
>>
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>
>
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