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[profcheck] Add unknown branch weights for inlined strcmp/strncmp #160455

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Merged
merged 2 commits into from
Sep 26, 2025
Merged

[profcheck] Add unknown branch weights for inlined strcmp/strncmp #160455

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ad625af
[profcheck]Add the missing profile handling in for strcmp/strncmp.
Sep 24, 2025
23308e8
Merge remote-tracking branch 'upstream/main' into fixup/missing-prof-…
Sep 24, 2025
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17 changes: 13 additions & 4 deletions llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/ProfDataUtils.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
#include "llvm/Transforms/Utils/Local.h"
Expand Down Expand Up @@ -1283,11 +1284,19 @@ void StrNCmpInliner::inlineCompare(Value *LHS, StringRef RHS, uint64_t N,
Value *VR =
ConstantInt::get(CI->getType(), static_cast<unsigned char>(RHS[i]));
Value *Sub = Swapped ? B.CreateSub(VR, VL) : B.CreateSub(VL, VR);
if (i < N - 1)
B.CreateCondBr(B.CreateICmpNE(Sub, ConstantInt::get(CI->getType(), 0)),
BBNE, BBSubs[i + 1]);
else
if (i < N - 1) {
BranchInst *CondBrInst = B.CreateCondBr(
B.CreateICmpNE(Sub, ConstantInt::get(CI->getType(), 0)), BBNE,
BBSubs[i + 1]);

Function *F = CI->getFunction();
assert(F && "Instruction does not belong to a function!");
std::optional<Function::ProfileCount> EC = F->getEntryCount();
if (EC && EC->getCount() > 0)
setExplicitlyUnknownBranchWeights(*CondBrInst, DEBUG_TYPE);
} else {
B.CreateBr(BBNE);
}

Phi->addIncoming(Sub, BBSubs[i]);
}
Expand Down
12 changes: 8 additions & 4 deletions llvm/test/Transforms/AggressiveInstCombine/inline-strcmp-debugloc.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -5,22 +5,23 @@

@.str = constant [3 x i8] c"-h\00"

define i32 @main() {
; CHECK-LABEL: define i32 @main() {
define i32 @main() !prof !8 {
; CHECK-LABEL: define i32 @main()
; CHECK: !prof [[PROF_0:![0-9]+]]
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: br label %[[SUB_0:.*]], !dbg [[DBG4:![0-9]+]]
; CHECK: [[SUB_0]]:
; CHECK-NEXT: [[TMP0:%.*]] = load i8, ptr null, align 1, !dbg [[DBG4]]
; CHECK-NEXT: [[TMP1:%.*]] = zext i8 [[TMP0]] to i32, !dbg [[DBG4]]
; CHECK-NEXT: [[TMP2:%.*]] = sub i32 [[TMP1]], 45, !dbg [[DBG4]]
; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i32 [[TMP2]], 0, !dbg [[DBG4]]
; CHECK-NEXT: br i1 [[TMP3]], label %[[NE:.*]], label %[[SUB_1:.*]], !dbg [[DBG4]]
; CHECK-NEXT: br i1 [[TMP3]], label %[[NE:.*]], label %[[SUB_1:.*]], !dbg [[DBG4]], !prof [[PROF_1:![0-9]+]]
; CHECK: [[SUB_1]]:
; CHECK-NEXT: [[TMP4:%.*]] = load i8, ptr getelementptr inbounds (i8, ptr null, i64 1), align 1, !dbg [[DBG4]]
; CHECK-NEXT: [[TMP5:%.*]] = zext i8 [[TMP4]] to i32, !dbg [[DBG4]]
; CHECK-NEXT: [[TMP6:%.*]] = sub i32 [[TMP5]], 104, !dbg [[DBG4]]
; CHECK-NEXT: [[TMP7:%.*]] = icmp ne i32 [[TMP6]], 0, !dbg [[DBG4]]
; CHECK-NEXT: br i1 [[TMP7]], label %[[NE]], label %[[SUB_2:.*]], !dbg [[DBG4]]
; CHECK-NEXT: br i1 [[TMP7]], label %[[NE]], label %[[SUB_2:.*]], !dbg [[DBG4]], !prof [[PROF_1]]
; CHECK: [[SUB_2]]:
; CHECK-NEXT: br label %[[NE]], !dbg [[DBG4]]
; CHECK: [[NE]]:
Expand All @@ -46,11 +47,14 @@ declare i32 @strcmp(ptr, ptr)
!4 = !DILocation(line: 258, column: 10, scope: !5)
!5 = distinct !DISubprogram(name: "streq", scope: !1, file: !1, line: 257, type: !7, scopeLine: 257, unit: !0, retainedNodes: !2)
!7 = !DISubroutineType(types: !2)
!8 = !{!"function_entry_count", i64 1000}
;.
; CHECK: [[META0:![0-9]+]] = distinct !DICompileUnit(language: DW_LANG_C11, file: [[META1:![0-9]+]], producer: "{{.*}}clang version {{.*}}", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: [[META2:![0-9]+]], retainedTypes: [[META2]], globals: [[META2]])
; CHECK: [[META1]] = !DIFile(filename: "test.c", directory: {{.*}})
; CHECK: [[META2]] = !{}
; CHECK: [[PROF_0]] = !{!"function_entry_count", i64 1000}
; CHECK: [[DBG4]] = !DILocation(line: 258, column: 10, scope: [[META5:![0-9]+]])
; CHECK: [[META5]] = distinct !DISubprogram(name: "streq", scope: [[META1]], file: [[META1]], line: 257, type: [[META6:![0-9]+]], scopeLine: 257, spFlags: DISPFlagDefinition, unit: [[META0]], retainedNodes: [[META2]])
; CHECK: [[META6]] = !DISubroutineType(types: [[META2]])
; CHECK: [[PROF_1]] = !{!"unknown", !"aggressive-instcombine"}
;.