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[PGO] Fix branch probability remarks assert 

Fixed counter/weight overflow that leads to an assertion. Also fixed the help
string for pgo-emit-branch-prob option.

Differential Revision: https://reviews.llvm.org/D44809

llvm-svn: 328653
This commit is contained in:
Rong Xu 2018-03-27 18:55:56 +00:00
parent 0a0c871f60
commit 662f38b16f
3 changed files with 39 additions and 7 deletions
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16
llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
View File

@ -224,8 +224,8 @@ static cl::opt<bool>
EmitBranchProbability("pgo-emit-branch-prob", cl::init(false), cl::Hidden,
cl::desc("When this option is on, the annotated "
"branch probability will be emitted as "
" optimization remarks: -Rpass-analysis="
"pgo-instr-use"));
"optimization remarks: -{Rpass|"
"pass-remarks}=pgo-instrumentation"));
// Command line option to turn on CFG dot dump after profile annotation.
// Defined in Analysis/BlockFrequencyInfo.cpp: -pgo-view-counts
@ -1595,13 +1595,15 @@ void llvm::setProfMetadata(Module *M, Instruction *TI,
if (BrCondStr.empty())
return;
unsigned WSum =
std::accumulate(Weights.begin(), Weights.end(), 0,
[](unsigned w1, unsigned w2) { return w1 + w2; });
uint64_t WSum =
std::accumulate(Weights.begin(), Weights.end(), (uint64_t)0,
[](uint64_t w1, uint64_t w2) { return w1 + w2; });
uint64_t TotalCount =
std::accumulate(EdgeCounts.begin(), EdgeCounts.end(), 0,
std::accumulate(EdgeCounts.begin(), EdgeCounts.end(), (uint64_t)0,
[](uint64_t c1, uint64_t c2) { return c1 + c2; });
BranchProbability BP(Weights[0], WSum);
Scale = calculateCountScale(WSum);
BranchProbability BP(scaleBranchCount(Weights[0], Scale),
scaleBranchCount(WSum, Scale));
std::string BranchProbStr;
raw_string_ostream OS(BranchProbStr);
OS << BP;

8
llvm/test/Transforms/PGOProfile/Inputs/large_count_remarks.proftext Normal file
View File

@ -0,0 +1,8 @@
# :ir is the flag to indicate this is IR level profile.
:ir
test
25571299074
2
40000000000
20000000000

22
llvm/test/Transforms/PGOProfile/large_count_remarks.ll Normal file
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@ -0,0 +1,22 @@
; RUN: llvm-profdata merge %S/Inputs/large_count_remarks.proftext -o %t.profdata
; RUN: opt < %s -pgo-instr-use -pgo-test-profile-file=%t.profdata -pass-remarks=pgo-instrumentation -pgo-emit-branch-prob -S 2>&1| FileCheck %s --check-prefix=ANALYSIS
; RUN: opt < %s -passes=pgo-instr-use -pgo-test-profile-file=%t.profdata -pass-remarks=pgo-instrumentation -pgo-emit-branch-prob -S 2>&1| FileCheck %s --check-prefix=ANALYSIS
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define i32 @test(i32 %i) {
entry:
%cmp = icmp sgt i32 %i, 0
br i1 %cmp, label %if.then, label %if.end
if.then:
%add = add nsw i32 %i, 2
br label %if.end
if.end:
%retv = phi i32 [ %add, %if.then ], [ %i, %entry ]
ret i32 %retv
}
; ANALYSIS:remark: <unknown>:0:0: sgt_i32_Zero {{.*}}50.00% (total count : 40000000000)