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[PGO] Support PGO annotation of CallBrInst

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We currently instrument CallBrInst but do not annotate it with
the branch weight. This patch enables PGO annotation of CallBrInst.

Differential Revision: https://reviews.llvm.org/D133040
This commit is contained in:
Rong Xu 2022-09-01 14:13:50 -07:00
parent de3633e746
commit 0caa4a9559
5 changed files with 25 additions and 2 deletions
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2
llvm/lib/Analysis/BranchProbabilityInfo.cpp
View File

@ -380,7 +380,7 @@ bool BranchProbabilityInfo::calcMetadataWeights(const BasicBlock *BB) {
const Instruction *TI = BB->getTerminator();
assert(TI->getNumSuccessors() > 1 && "expected more than one successor!");
if (!(isa<BranchInst>(TI) || isa<SwitchInst>(TI) || isa<IndirectBrInst>(TI) ||
isa<InvokeInst>(TI)))
isa<InvokeInst>(TI) || isa<CallBrInst>(TI)))
return false;
MDNode *WeightsNode = TI->getMetadata(LLVMContext::MD_prof);

2
llvm/lib/IR/Verifier.cpp
View File

@ -4502,6 +4502,8 @@ void Verifier::visitProfMetadata(Instruction &I, MDNode *MD) {
ExpectedNumOperands = IBI->getNumDestinations();
else if (isa<SelectInst>(&I))
ExpectedNumOperands = 2;
else if (CallBrInst *CI = dyn_cast<CallBrInst>(&I))
ExpectedNumOperands = CI->getNumSuccessors();
else
CheckFailed("!prof branch_weights are not allowed for this instruction",
MD);

3
llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
View File

@ -1398,7 +1398,8 @@ void PGOUseFunc::setBranchWeights() {
if (TI->getNumSuccessors() < 2)
continue;
if (!(isa<BranchInst>(TI) || isa<SwitchInst>(TI) ||
isa<IndirectBrInst>(TI) || isa<InvokeInst>(TI)))
isa<IndirectBrInst>(TI) || isa<InvokeInst>(TI) ||
isa<CallBrInst>(TI)))
continue;
if (getBBInfo(&BB).CountValue == 0)

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

@ -0,0 +1,8 @@
# :ir is the flag to indicate this is IR level profile.
:ir
a
784007059655560962
2
100
80

12
llvm/test/Transforms/PGOProfile/callbr.ll
View File

@ -1,4 +1,8 @@
; RUN: opt -passes=pgo-instr-gen -S 2>&1 < %s | FileCheck %s
;
; RUN: llvm-profdata merge %S/Inputs/callbr.proftext -o %t.profdata
; RUN: opt < %s -passes=pgo-instr-use -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
define i32 @a() {
entry:
@ -15,3 +19,11 @@ b:
%0 = load i32, ptr %retval, align 4
ret i32 %0
}
; USE-LABEL: @a
; USE-SAME: !prof ![[BW_ENTRY:[0-9]+]]
; USE: callbr void asm sideeffect
; USE: to label
; USE-SAME: !prof ![[BW_CALLBR:[0-9]+]]
; USE ![[BW_ENTRY]] = !{!"function_entry_count", i64 100}
; USE ![[BW_CALLBR]] = !{!"branch_weights", i32 80, i32 20}